Classic Rotary Phones Forum

Telephone Identification, Repair & Restoration => Telephone Restoration Projects and Techniques => Sanding Plastic - Paper and Chemical Tips & Techniques => Topic started by: royalbox on January 16, 2017, 09:01:58 AM

Title: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 16, 2017, 09:01:58 AM
I thought I'd document my attempted restoration of this UK GPO 746 telephone I recently bought and hopefully get some tips along the way. It's from 1971 and is in the less often seen "Topaz Yellow" which is a mustardy yellow, but is badly discoloured. I've already made a start, but first here's some pictures of the phone taken by the seller.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 16, 2017, 09:11:11 AM
Here's after cleaning showing the original colour under the dial surround.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 16, 2017, 09:22:56 AM
Here's after sanding with 600, 1000, 1500 grit wet and dry. I've only done the initial 600 grit on the handset in this picture. I'm waiting for some 2000 grit to arrive as well as they didn't have any locally.

As you can see, I sanded half the handset at a time as I wanted to prevent flattening the divider line running down the centre as much as possible.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 16, 2017, 09:41:40 AM
Now, here's a question: Has anyone here tried "acetone vapour smoothing" as used by people doing 3D printing with ABS? I found a post asking about it but haven't found a post where someone has tried it. It seems it could be a good way to smooth out the final sanding scratches if done carefully.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: twocvbloke on January 16, 2017, 11:09:20 AM
Not acetone, but Methyl Ethyl Ketone (or MEK) has been used for smoothing the plastics of restored phones:

http://www.classicrotaryphones.com/forum/index.php?topic=5260.0
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 16, 2017, 04:21:08 PM
Yes, the vapour smothing post I found took me to that post. It would use a lot of liquid to dip even half the phone at a time I think. I want to try the vapour method but perhaps I'd need to wait for the warmer weather so I can do it outdoors for safety. Not sure. Would like to hear if anyone has tried it though.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on January 17, 2017, 08:18:55 AM
From what I've seen of the vapour smoothing for 3d prints it seems to reduce the overall definition. In prints with the 'steps' in them it's desirable, but on a phone that may have embossed detail it might damage it. My guess is you'll end up with something that looks like rubbed hallmarks on over-polished silver.

I think the best way is a liquid retrobright bath. However the jury is out if that method is permanent or not.

Andy.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 17, 2017, 01:01:21 PM
Hello Andy,
I've got rid of the discolouring with sanding, my aim is to try and smooth out the sanding marks as much as possible before polishing. I was thinking that a short time in the vapour may be enough to do it as the scratches will be very fine, especially when I do the final 2000 grit. Nothing like those ridges on the 3D prints you see on youtube.

I'll have another read of that dipping method thread but I'm not sure how easy or cheap it is to get those chemicals here in the UK.

By the way, have you seen this ebay seller (http://www.ebay.co.uk/itm/REPLACEMENT-GPO-BT-746-TELEPHONE-CASE-SET-/192070734220?var=&hash=item2cb84ed18c:m:mfo9t-U-jf0k6RVjCgyP9rg) selling brand new 746 cases? I wonder if he got hold of an original mould. Not buying one just thought it was interesting.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on January 17, 2017, 01:38:39 PM
Hi Barry,

That MEK stuff is commonly sold by model shops here in the uk in a little glass bottle under the name of 'Plastic Weld'. It's used for assembling plastic scale models without the mess of glue that goes all stringy. I think I'd be tempted to try a very fine mist spray of acetone personally.  You need to absolutely soak the surface so the plastic liquifies and then sets again nice and flat. I think you'll have problems on vertical surfaces because the thin layer you melt will want to run down and you'll get an effect like the really old glass in church windows where it's thicker at the bottom than it is at the top.

Regarding that E-Bay seller, I bought some new clear dial opelsfrom them. They're pretty good and I'm getting ready for some more. However you have to be careful because some of the things they are selling are to their own design and not at all historically accurate for the purposes of restoration. The dial finger wheels are wrong, because proper coloured finger wheels have a brass and steel spring embedded into them which you put a screwdriver under to flick the dial opel out. Also orange 746 cases never existed in reality. A very small batch were made as a test, but they never went into production. Also the alpha numeric dial plates for fitting to dial 21 were only ever made with a white background (these guys do a cream one) and were only fitted to dials with black finger wheels, which were a replacement for dial 12s on bakelite phones. As far as I know they were never used on 700 series.

Also the alpha numeric dial bezels in various colours are not correct. they should be flat (without the lugs to hold them in place) and made from a clear plastic, with the lettering and background colour applied to the back then secured to the phone using a metal ring fitted to the inside. The GPO would never have allowed a plastic ring with the printing on the surface because they knew the printing would rub off with many years of heavy use.

The buttin blanks are quite good, but the coloured buttons for 746 tyes themselves never existed. Like the finger wheel they were always clear on a 746 to cut down on the stock keeping requirements of different types. You can have coloured ones for a 706 though.

Of course accuracy doesn't matter to some people, but personally I always try to restore things the way they were, not 'enhance' or change them. I guess that's my museums background showing through!  ;D

Andy.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 17, 2017, 03:36:20 PM
Thanks Andy for the tips. Interesting information about that reproduced stuff on ebay. I knew that the coloured buttons were not provided originally but didn't know about all the other things you mentioned. Also I think a new case with an old handset might look a bit odd. I expect the colours and finish wouldn't match quite right.

Anyway, as I say, I wasn't going to buy one. The enjoyment is in trying to restore the old ones for me, even if I'm no expert.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 18, 2017, 04:13:37 PM
The 2000 grit wet and dry sandpaper arrived today, won't be able to do any sanding until the weekend now.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on January 19, 2017, 11:24:54 AM
I've only tried sanding one phone as an experiment. It's an ivory 706 that had discoloured to a very dark yellow. I found it really hard work and discovered I needed quite coarse sandpaper to get the discolouring off. Then I finished with finer grades wet with T-Cut. To finish I used wire wool, again with T-Cut. Final polish was yet more T-cut on a rag.

Another thing I tried was a dremmel type thing with a polishing mop. Don't even bother trying this... It spins too fast and creates too much heat, which starts to melt the plastic and take little gouges out.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: twocvbloke on January 19, 2017, 01:11:04 PM
Yeah, if using a machine polishing tool, you need to slow it right down for plastic, higher speeds are more suited to metal, though even brass can break apart if it gets too hot when polishing (as I know, ruined a cheap duplex burner lamp about 10 years ago polishing it with a Kirby Handy Butler polisher, which was just way too fast and harsh for the brass)...
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 20, 2017, 10:05:18 AM
Thanks for the tips, I won't use any type of drill on it.

I've just re-read the thread (http://www.classicrotaryphones.com/forum/index.php?topic=5260.0) twocvbloke linked to earlier. It ends without any definite conclusion, no final results of a whole phone. Still, I think it might be interesting to try this dipping method.

You can get MEK quite easily on ebay it seems but he suggests mixing it with thinners. As the scratches on the phone are quite fine (I've done up to 2000 grit now), I wondered if a weaker mix of MEK with thinners would work. Not sure whether there is any benefits with using acetone vs MEK.

As I just bought a badly discoloured two-tone grey 746 for little money, I'm going to sand the main case on that and experiment on it first. I'll update as I go along in case anyone's interested.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: TelePlay on January 20, 2017, 10:31:05 AM
There are quite a few topics dealing with chemical smoothing by dipping, vapor and most recently, chemical sanding. This is but one but one which I've found to work quite well.

     http://www.classicrotaryphones.com/forum/index.php?topic=17145.msg176752#msg176752

I've taken scratches out of ABS and soft plastic using a coarse sand paper (320, 400 or 600 with water depending on the depth of the scratch) and worked my way up to 1000. Then using a mixture of 50/50 acetone and denatured alcohol or straight denatured alcohol on a rag, have been able to get rid of the 1000 grit sand marks quickly. Got it to a point where Meguiar's, Novus 2 and/or buffing would produce a flawless finish.

I started with 10% acetone and worked up to 50%. More than that "cut" too much and left cotton cloth marks on the surface. It's a trial and error leaning curve for each person. Then intent of chemical sanding is to remove a thin layer of plastic just as sanding would but with a solvent and cloth, no additional "sand" marks are created.

You can search the forum for chemical sanding to find other topics. This is one from a few months ago where Christian used denatured alcohol on soft plastic to a remarkable end.

     http://www.classicrotaryphones.com/forum/index.php?topic=17163.0

You may want to give this a try. Minimum expense, effort, time and danger for maximum results.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 20, 2017, 03:25:21 PM
Thanks a lot TelePlay.
A couple of questions:
1. Is denatured alcohol the same as mentholated spirits? If so, I already have some.

2. Is acetone a thin liquid? If so, I'm thinking of what Andy said earlier about creating a fine mist. I was wondering about getting a small bottle that creates a mist (seen them on ebay) and trying that so there's no touching the surface with a rag. Could even do one side at a time so that the phone could be angled so there is no run off causing the possible problems that Andy mentioned.

Does that sound reasonable? I'd have to make sure or hope that the chemicals don't eat away at the spray bottle.

I've been sanding the grey phone case ready for testing. I know it's been said before but it really is a lot of work isn't it!

Thanks again,
Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: twocvbloke on January 20, 2017, 03:27:21 PM
Acetone is better known as nail polish remover, which is a watery liquid, though usually watered down a bit for use with removing finger nail paint... :)
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: TelePlay on January 20, 2017, 05:37:38 PM
Quote from: royalbox on January 20, 2017, 03:25:21 PM
Thanks a lot TelePlay.
A couple of questions:
1. Is denatured alcohol the same as mentholated spirits? If so, I already have some.

2. Is acetone a thin liquid? If so, I'm thinking of what Andy said earlier about creating a fine mist. I was wondering about getting a small bottle that creates a mist (seen them on ebay) and trying that so there's no touching the surface with a rag. Could even do one side at a time so that the phone could be angled so there is no run off causing the possible problems that Andy mentioned.

Does that sound reasonable? I'd have to make sure or hope that the chemicals don't eat away at the spray bottle.

I've been sanding the grey phone case ready for testing. I know it's been said before but it really is a lot of work isn't it!

Thanks again,
Barry.

Yes, here is a definition of Denatured Alcohol:  "Denatured alcohol, also called methylated spirits or denatured rectified spirit, is ethanol that has additives to make it poisonous, bad tasting, foul smelling or nauseating, to discourage recreational consumption. In some cases it is also dyed. Pyridine, methanol,[1] or copper sulphate[citation needed] can be added to make denatured alcohol poisonous, and denatonium can be added to make it bitter."

It's ethanol or ethyl alcohol (C2H5OH), the good stuff in pure form known as booze but it has been "poisoned" with inedible chemicals the have a boiling point so near to ethanol that they can not be distilled out, they come over at the same temperature making it near impossible to clean denatured ethanol. Methanol is CH3OH and Isopropanol is C3H7OH, neither of which is good to ingest. Both of which can be used to "cut" or dilute acetone to a desirable ratio.

Acetone is very thin and has a low boiling point (evaporates quickly at room temperature) was the original nail polish remover (probably in a diluted form) decades ago but today they have two types of remover, one with acetone and one made with everything but acetone. Pure acetone is very volatile and in a closed space and used in high volume, can evaporate to the point of having an explosive atmosphere where a spark could just wreck your day. Ventilation is good. Nail polish remover also has color and fragrance additives that may have a bad  effect on plastic. Pure acetone is available at hardware stores, home supply stores and paint stores by the quart or gallon. I buy it my the gallon because it is a great de-greaser to remove anything and everything from a metal surface I am going to paint (using a rubber glove on the hand that is holding the item to be painted) to keep finger oils off of the cleaned metal). A small amount on a paper tower works best be make sure to dispose the towels in an outdoor open can so the acetone can safely evaporate.

Back to plastic, I mix 10 ml of acetone with 10 ml of denatured alcohol as needed and the vapors from that are really not a problem if you keep the mixture capped.. When experimenting with chemical sanding, I started mixing acetone with water, 5% acetone, and worked my way up to 65% to get results. Since both acetone and denatured alcohol can dissolve plastic and WEBellSystemChristian found using pure denatured alcohol worked well on some plastics, I worked my way up to 50-50 which I like for ABS. A 50-50 mix works on a cloth by letting the acetone do its thing first, the acetone evaporates first leaving ethanol in the rag to smooth out the plastic softened by the acetone. It is a controlled process over a small area, a few square inches. Hard to keep a large area "wet" so smaller areas, say 1/2 the side of a 500 at a time. As you work with it, if you try this, you will see what I mean. It's best to keep rubbing an area until most of the liquids have evaporated leaving a fairly smooth finish ready for buffing or Novus.

Dipping for misting or washing a housing with acetone, MEK or DiChloroEthane to me is a mess and hard to control how much touches or stays on any part of the phone. It also will blur the emblem under the hand hold or on the handset. There is a topic somewhere on the forum where a member experimented with dipping but IIRC, it did not turn out well or it didn't work well. Also, if misting, you are creating an explosive atmosphere even faster. Also, the point of dipping is to "wash off" a layer of plastic so misting would not do much more than possibly causing pits or crackling. WE had a huge machine to do this in a very controlled process on a convey belt in an industrial type room. Somewhere on the forum is a pdf file that pretty well describes what they did and the chemical they used at temperature. Spraying acetone on plastic I think would be similar to spaying Windex on a dirty window and letting it dry by itself. Once you spray acetone on plastic, you can not rub the plastic with anything, or even touch it, without leaving bad marks in the plastic. If you ever accidentally had a drop of pure acetone hit anything plastic, you know what I mean. Instant damage.

You can use anything that dissolves plastic. Isopropanol does not cut as well as ethanol. Haven't tried methanol. Acetone cuts plastic very fast. MEK does as well. Water does not. The idea is to get a mixture that meets your needs. I do the 50-50 acetone/ethanol first and then pure ethanol. Christian just uses ethanol. As you go to large alcohols, butanol, pentanol, hexanol, etc, they become larger and thicker and don't know of they would do anything to plastic. Hexane, or rubber cement thinner, dissolves plastic but is expensive and hard to find. Butane is a gas and not sure what pentane is, probably has a volatility like acetone. Acetone is a ketone as is MEK, methyl ethyl ketone. MEK substitute is not the same.

If you don't have a junk housing to practice on, try your mixture on a small spot inside. If you cloth sticks to the plastic right away, use less acetone and ethanol or dilute pure ethanol with water. Each time I do it, I carefully watch the first application for problems and if none, just do the whole piece. If you do get a cloth mark or fingerprint (best to use a rubber exam glove to avoid fingerprints and to keep the chemicals from being adsorbed into your skin - I use a finger cot on the applying finger (1000 are cheap on eBay).

This was a lot longer than I thought it would be but I've been working with this technique for a few years, as has WEBellSystemChristian (and others including dencins who pioneered the use of chemicals on surfaces years ago).
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 21, 2017, 07:32:39 AM
Thanks for all the info John and twocvbloke, really helpful.
I just ordered some acetone online as there are no descent shops that would sell it round here. I will try your method and post results.

I've been busy sanding the grey "practice" phone case some more. Really hard work, very discoloured but almost there. It has a crack on the front edge so I will investigate the best way to try and fix that in the mean time. I bought a small bottle with a dropper on the end in case that could be used to squirt a small amount of acetone in or around the crack to melt it together or something, but will read up on it first.

Thanks again,
Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 22, 2017, 09:45:15 AM
I hope it's not considered off-topic, but while I'm waiting for stuff to arrive, here's some photos of the boring office grey phone I've been sanding.

1. As arrived, pre clean
2. Post sanding
3. Crack on front

I've glued the front with Humbrol poly cement and am holding it together with strong gorilla tape until it dries.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: twocvbloke on January 22, 2017, 10:26:45 AM
Looks like a nice job there getting the original grey back, the greyest I've seen on my 746 phones is not actually a 746 (officially) but my military Mk.28 (pictured below, middle phone, the left is an 8746 with Handset No.17A, and the right is a Pye-TMC 1746 branded as a Storno radio product), and even that's not entirely original to the light grey they used due to the usual age-yellowing, even though it's seen very little in the way of sunlight exposure... :)
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on January 22, 2017, 11:37:10 AM
Three nice phones there Twocvbloke. Interesting variants on a theme too.

Barry, if you have any more cracked cases then it might be worth having a go at 'welding' the crack with acetone. There are a few threads on here about it, but basically paint a bit of acetone (or MEK if you prefer) into the back of the crack, which will seep into the crack with capillary action and stabilize it. Then you can 'v' out the front of the crack with a dremmel. You then mix some scrap ABS the same colour into a small jar of acetone. Keep adding the plastic until you have a runny paste. Note you might have to let it stand over night to get the plastic fully disolved on the acetone. You can then fill the 'v' with the runny plastic paste just a bit proud of the surrounding surface. Once dry, sand it flat and it seems (I haven't tried it myself yet) that the filled crack becomes totally invisible. I've seen cases with broken and missing parts built back up with this techniqe and it looks pretty good. The main thing to watch for is that you don't get any air bubbles in your mixture.

Having thought about it, I agree that misting probably wouldn't work. My guess is it would probably leave an orange peel like effect.

Andy.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 22, 2017, 12:42:14 PM
Twocvbloke, Three grey ones! You must have quite a collection.

My grey one has a light grey dial ring that matches the case which seems to be less common. I sometimes see the 2-tone green phones with a light dial ring as well. Perhaps it depend on the manufacture.

The trouble with sanding -- apart from the hard work -- is that it does take away some of the sharp lines like on the rear of the 746 just before it curves up into the handle. Also, the line down the centre of the handset if you're not careful.

Andy, yes, that's what I had in mind, I've been reading those topics. I don't have a dremel but maybe I could use a small round file. I have acetone on order as mentioned previously so I will try it.

I have a green one with a crack in the same place as the grey one and a blue 746 that has a small chunk missing from the front corner. Rather than take away plastic from inside the phone I was wondering about buying one of those new dummy buttons (http://www.ebay.co.uk/itm/706-GPO-TELEPHONE-Blanking-Button-ALL-COLOURS-NEW-FREE-P-P-/282319294888?var=&hash=item41bb8a91a8:m:mBgQn3vvnxRxbmMoTc_w3rw) and melting some of that. The 706 version is a bit cheaper at £2 including postage. I don't know how accurate the newly manufactured colours are though. Still, that's for later.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on January 22, 2017, 01:08:30 PM
Barry,

Don't experiment on the blue one too much. It's the rarest original colour so you'd find replacing it or getting spare casing parts quite difficult.

I think the light coloured dial bezels came later than the dark ones. I've got green and grey ones here. I've also got a modernised 706 with a dial like a 746 that also has teh light coloured bezel.

I'm not a fan of sanding unless I absolutely have to do it. This is normally because something like glue has been dropped on the phone at some point in it's history or there are really deep scratches. If a phone is just discoloured I tend to live with it. I've got some quite nice two tone brown Ericsson N1900s that actually started life as grey ones, although you'd never know it now!

If you want original colours, then keep an eye out for 706s with Diakon cases. These were fitted up until 1963 and don't fade at all. They are also a lot more shiny than ABS. The Diakon finish almost looks like coloured glass. The down side of diakon is it's a lot more brittle, so you run the risk of damage if buying from someone who has to post it to you. I've had a couple from E-Bay that have been write-offs when they've arrived here.

You could try one of those new buttons as a source of plastic. It might be worth checking they're made out of ABS forst though as I don't know if other plastics would work the same. I might even be able to find a bit of something light green from the spares box here. I doubt I've got anything blue though. I'll have a look and get back to you on that.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 22, 2017, 01:32:07 PM
Thanks Andy.

I repaired the crack in the green phone with glue like I'm doing to the grey one here. However, you can still see it's a crack if you look at it. I could probably "steal" a bit on plastic from inside on the green one but not really with the blue one as it's a chunk missing.

The blue one has quite a lot of deep digs and scratches etc, and so I would like to try and get it looking good again. This would be one that I will use as a main phone.

I've bought 7 phones and 3 of those came with cracks or breaks that appeared to happen during shipping. People just don't package them well, it's really annoying.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: twocvbloke on January 22, 2017, 05:01:10 PM
Quote from: andy1702 on January 22, 2017, 11:37:10 AM
Three nice phones there Twocvbloke. Interesting variants on a theme too.

Thanks, it's the variations I like about them three, I'm not that much of a two-tone grey or ivory fan, so these three I have simply for those differences (and the 8746 was a bog-standard one but I had that 17A handset (bought from Bob Freshwater himself!!) that needed a home so that was perfect for it!)... :)

Quote from: royalbox on January 22, 2017, 12:42:14 PM
Twocvbloke, Three grey ones! You must have quite a collection.

It's been a while since I last counted, but, I think it's somewhere around 30-ish, most of which are GPO & BT phones with some US & Canadian phones thrown in... :)
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 29, 2017, 09:50:54 AM
The acetone arrived.
I tried the 50% mix of acetone and methylated spirits on one side of the phone as John described. The results were a sort of satin finish, didn't really get rid of the fine scratches as I hoped. Probably need to mess about with the ratio a bit more. However, I really wanted to try the acetone vapour smoothing method, so I did.

I tried the dial bezel first. I used a biscuit tin that was only about 2 inches high, soaked a folded paper kitchen towel with acetone and placed it unfolded into the bottom. I put the dial bezel facing up onto a small piece of glass, placed that onto the towel and closed the lid. I left it for half hour, checked the progress and was really pleased with the results. It looked like new plastic, very smooth no sanding lines and no misshaping.

Next I tried the main phone case in a polypropylene box with a snap on lid. The box was about the right length and width but perhaps a bit high.

First, I placed two soaked paper towels, one each side held in place by the lid. After about 3 hours total, the result wasn't as good as the bezel. The sides were the best but the top just hadn't been affected enough. I re-soaked a piece of towel and placed it on the inside of the lid this time. Again, after 3 hours with checking in-between, the sides and back were good but the top wasn't. It had some crazing effect on it (see pictures). I'm wondering if it's because it's a horizontal surface.

Anyway, I'm going to sand it down and try again. I'll do the treatment John mentioned over the whole case first. I'm waiting for some magnets to arrive so I can attach the paper towels to the sides of the box more easily. I may add towels to all 4 sides but not the top and see how that goes. If I can get the top to look as good as the sides I'd be happy. I'd then use some Novus 2 as a final finish.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 29, 2017, 05:48:14 PM
Can anyone help me with covering the crack on the grey phone as posted earlier (http://www.classicrotaryphones.com/forum/index.php?topic=17463.msg180985#msg180985)? The crack has been glued together but is still noticeable so I'd like to fill it with either glue or try to dissolve some grey plastic as shown in other threads then sand. The problem is that I need to create a groove along the crack in order to fill but I don't have a dremel tool. Any ideas on what I can use? I don't think a file will work, the crack is not straight for a start, but correct me if I'm wrong. Thanks for any help,
Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: twocvbloke on January 29, 2017, 06:29:56 PM
One way to create a groove is to just carefully scratch along it with the pointy end of a stanley knife (or similar) blade, takes a while but you get there in the end... :)
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 30, 2017, 10:41:48 AM
Thanks twocvbloke, that worked well.
I'm currently building up a layer of dissolved plastic in the groove by dabbing it on with a brush until the acetone evaporates and then repeating as outlined in another thread. Apparently bubbles will form, but we'll see how it goes.
Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on January 30, 2017, 01:07:02 PM
Sounds like you're working along the right lines there Barry. I've not tried the plastic disolved in acetone crack repair yet, but I think it will work judging by the results on other threads.

I do have a green cased 706 here somewhere that I seem to remember had a nastyu crack up the side of the case all theway to the dial hole. I originally repaired it by putting superglue on the back of the crack and letting it run in by capillary action. But like you said, it still looks like a crack. So I might try digging the phone out from wherever I put it, V-ing out the crack and having a go at the same thing you're trying.

What I'd really like to know is does this disolved plastic trick also work on diakon? I have an black diakon case that got damaged in the post and I'd previously thought may be beyond salvation. But if it can be welded in this way it could be the answer.

As for the crazing on your vapour treated phone... I wonder if it's something to do with vapour collecting on the lid, condensing and dripping back onto the case? What would happen if you fitted a small electric fan (maybe from an old computer) in the box to circulate the vapours? Just a thought.

Andy.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 30, 2017, 02:21:40 PM
Hello Andy,
So far I've dabbed on liquid at least 10 times but there is still a groove. I read this post (http://www.classicrotaryphones.com/forum/index.php?topic=5059.msg64001#msg64001) where he ended up just dabbing acetone on some ABS to soften it then scraped it off and pasted it into the groove. I'd recommend waiting to see how mine turns out before trying it on your green phone, I'll keep you informed of how it goes.

You could be right about the vapour condensing and dripping, as there were a few marks here and there that looked liked something had dripped.
Good idea about the fan. One of the youtube videos on vapour smoothing used a PC fan but it must be one that doesn't dissolve in acetone obviously, but also must be brushless (if I remember correctly) so as not to cause a possible spark. Think I'll look that video up again to check and get a cheap fan. Definitely worth trying.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 30, 2017, 02:36:23 PM
Also, I bought a couple of original false buttons in grey and blue that were on ebay. They could be a good source of ABS to disolve for filling cracks and mending breaks as they may be closer in colour and material than the newly manufactured ones.
Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on January 31, 2017, 05:24:06 AM
Just a couple of pictures of progress on the grey phone:

1. The groove cut along the crack.
2. Groove filled with dissolved plastic from the supporting ribs inside the phone.

I dabbed the liquid into the groove. Once the acetone evaporates, it appears to me that some of the plastic creates a hump either side of the groove if you see what I mean. I'm not entirely sure whether the groove is filled or whether it is still below the surface of the rest of the case. Won't know until it's sanded I suppose. Hope I can get it looking good with sanding. Will leave it for several days or a week to harden.
Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on January 31, 2017, 10:37:03 AM
I wonder if you've made your liquified ABS a bit weak? I saw something written somewhere that said you should only use a little acetone but disolve plenty of ABS into it so it makes it more of a runny paste rather than a liquid, then smooth it on with some kind of tiny spatula.

Andy.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on February 04, 2017, 05:42:08 AM
Hello Andy,
I used 4 small sliced-off pieces of plastic from the inside supports and a tiny bit of acetone. After I'd finished applying the liquid as above I decided to let the acetone evaporate a bit to see if I could get a paste like consistency. However, being such a tiny amount, it went from runny to completely evaporated in a very short time. I think you'd have to dissolve quite a bit of plastic to be able to get a thicker consistency.

I sanded the repair and sure enough as was mentioned in that other post I linked to earlier, air bubbles appeared. Also, the repaired section is a bit darker than the surrounding plastic. Not a great success. It's currently drying, but I'll see what it looks like after the next "vapour trial" once the cheap fan I ordered has arrived.
Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on February 04, 2017, 12:44:51 PM
Reading through that other thread, it appears the air bubbles come from the solvent as it evaporates from within the disolved plastic patch. So I'm now wondering if there is a different way of liquifying the plastic without using solvent.

I know some 3d printers and also some of those 3d pens use ABS, which is heated up in the unit and spat out the nozzle as a stream. This has made me wonder if you could use a thin rod of ABS and an electric soldering iron to melt the crack and apply more material at the same time? As this doesn't involve solvent there shouldn't be any way for the air bubbles to form. I'll give it a try on a bit of scrap ABS and let you know what happens.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on February 04, 2017, 04:18:12 PM
Thanks Andy, I will be interested to see how you get on. I've also got a green one with a crack in a similar place and a blue one with a piece missing from the front edge.
Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: twocvbloke on February 04, 2017, 10:20:19 PM
Quote from: andy1702 on February 04, 2017, 12:44:51 PMI know some 3d printers and also some of those 3d pens use ABS, which is heated up in the unit and spat out the nozzle as a stream. This has made me wonder if you could use a thin rod of ABS and an electric soldering iron to melt the crack and apply more material at the same time?

You'd probably want to have a soldering iron with a variable temperature, too hot and you'll burn the plastic, which not only ruins the look, but also smells really bad...  :o
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: WEBellSystemChristian on February 06, 2017, 10:03:34 PM
Wow, this is the first time I've read this topic!

I'll address the most recent issue first. I've found that bubbles formed in Acetone 'pools' are very easily repairable. Simply put a drop of pure Acetone on the patch of bubbles, and 'blot' it out with your fingertip until the bubbles disappear, then let dry and sand.

I'm glad to see the chemical polishing method works for someone else! What is your phone made of? ABS? Tenite?

If it's Tenite, straight Denatured Alcohol (or mineral spirits) and polish (Novus #2) will work great. That will get rid of the surface imperfections your phone has after polishing.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: twocvbloke on February 06, 2017, 11:48:07 PM
Quote from: WEBellSystemChristian on February 06, 2017, 10:03:34 PMWhat is your phone made of? ABS? Tenite?

Pretty much all GPO phone shells after 1962 are made of ABS, prior to that it was Diakon (polymethyl methacrylate, also known as Perspex), we never used Tenite here for our phones, just Bakelite, Diakon and ABS...
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on February 11, 2017, 10:12:22 AM
Sorry it's been a while since updating, experiments have been ongoing though. I've had a few disappointments but yesterday had some great success.

First, thanks for the tip Christian. The other problem is that the patch is darker than the surrounding plastic. I need to sand the grey phone again now so have moved on to the original yellow phone of this thread.

I've been doing the ear and mouth pieces using the setup in the first picture. I'm using an empty Vanish "oxy-action" carton. Around the inside edge at the base is a piece of kitchen paper folded twice and held in place by magnets on the inside and outside of the carton. A piece of cardboard tube taped to the lid holds the ear/mouth piece in place. I clean the pieces with methylated spirits (denatured alcohol) and put blu-tack around the threads so they don't get exposed. Some acetone is dribbled onto the paper towel and the carton is screwed onto the lid (upside down). I leave it for 15 minutes and carefully unscrew the carton and remove it. I'm really pleased with the results, very smooth and shiny with no noticeable scratch marks.

Next post will be the yellow phone case.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on February 11, 2017, 10:29:26 AM
I decided to have a go at the yellow phone case. As the ear/mouth pieces worked well with the acetone soaked paper above them, I decided to do the same with the case. I used 2 sheets of kitchen paper taped to the lid of the case and other pieces around the edge. I also raised the phone up nearer to the top of the box than I had been with the grey case. No fan, just soaked the towel on the lid and added some around the sides. Put the lid on and waited 15 minutes, took the lid off and couldn't believe how good it looked. Nice and even treatment, very smooth and shiny.

There are a couple of places where I could have sanded more to get rid of the discolouring but it's hardly noticeable. Strangely, the ring under where the dial surround goes came out slightly less shiny but it doesn't matter as it's covered by the surround of course.

It came out so well that I decided to re-sand the handset before "vaping" to get rid of the still slightly discoloured areas. I'm very fussy.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: TelePlay on February 11, 2017, 10:38:07 AM
Quote from: royalbox on February 11, 2017, 10:12:22 AM
The other problem is that the patch is darker than the surrounding plastic.

That would make sense in that the interior plastic would not be changed by exposure to exterior conditions, inside is the original color while the housing exterior is probably faded, in this case. If the housing were darkened over time, the patch would be lighter.

That is a very nice looking yellow housing.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on February 12, 2017, 05:28:24 AM
I'm very impressed by those results! Looks like this could be the way to go to get a nice shine back on ABS, which never seems to be as shiny as Diakon.

Now I'm looking for a way to restore discolouring, particularly on grey and ivory cases, that doesn't involve having to expose them to sunlight, because here in the UK we don't have any !

Andy
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: twocvbloke on February 12, 2017, 05:53:44 AM
Quote from: andy1702 on February 12, 2017, 05:28:24 AMNow I'm looking for a way to restore discolouring, particularly on grey and ivory cases, that doesn't involve having to expose them to sunlight, because here in the UK we don't have any !

Andy

UV lamps that they use for curing fingernail paint in them salon places work well, slop on some peroxide solution, wrap in cling film, sit under the UV light, and bake for a few hours... :)

It's amazing what just Peroxide can do, watch this video on a Commodore 128 turn from yellow yuckiness to bold & white again (albeit done in the Texas sun, but, same process!!):

https://www.youtube.com/watch?v=wLp6bzG9exk

I need to try that someday on my Amiga A500 power supply (and A600 too looking at that picture again!) which is so yellow you'd think it was the same colour as this Topaz 746!!!  :o
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on February 12, 2017, 03:45:00 PM
Thanks John and Andy.
I did the handset, dial ring and blanking button today. The handset looks really good, very pleased with it. I'm glad I took the time to sand it some more to get rid of the discolouring I'd missed the first time. I will take some more pictures when all the parts are dry and when there's daylight, although it looks nicer in real life than the pictures show.

The dial ring and blanking button I did together. I had to do them again because it didn't work very well in the big container where the phone and handset were done. I think I had them too low in the container. Anyway, I redid them in a smaller container and they came out great. 15-20 minutes seems to be about right for me on parts sanded to 2000 grit. Maybe I don't need to sand that fine.

Turning back to the grey phone again, The crack filling didn't go very well really. Plastic was too dark for a start. Also, I noticed today that where I'd been sanding that area, it's got a bit thin and misshapen compared to the other side. Oops.

As there's not much plastic inside the 746 to steal, and as it's darker inside anyway, what can I do to get a reasonable job done on it? I read about using super glue in another thread. Does this work okay, or any other ideas? I really want to get it looking reasonable so I can sell it on again. It was never one I wanted to keep, I don't really like the grey and have bought too many phones lately.

Thanks all,

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on February 12, 2017, 05:42:52 PM
You think you bought too many phones? You should come and have a look here! Even I don't know how many there are. I took them to display at a local museum for a day before Christmas and filled up two 6ft long tables. Then realised I left a couple of cardboard boxes full at home!

Back on topic, superglue doesn't hide a crack at all. It still looks lime a crack, even if you apply the glue from the inside. I still have to try the welding with a soldering iron technique. Liquified plastic has worked for other people though, so maybe it's just your technique that was a bit off. From what you posted I think you might have made your mixture too runny. You need something more like a paste that you can trowell into the 'v' and leave a little high. Then try to sand the high bit without taking away any of the surrounding material. I now have a brown 776 with a huge crack so I'll probably try acetone on that. The problem is 776s were made in odd colours so getting some spare ABS the right colour will probably be tricky.

Andy.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on February 13, 2017, 11:40:23 AM
That's a lot of phones Andy!

It's more tricky than it sounds especially when you only have little fragments of plastic to use. However, I have now sacrificed grey and green button blanking plates to try and repair the cracks again. I'm trying something similar to the technique mentioned earlier. Once the liquid has evaporated a fair bit, press the solution down with my finger into the repair. I've done that once and am waiting for some more plastic to dissolve as I write this to fill it up again. I have blu-tack around the repair so I can build it up higher than the surrounding. We'll see how it goes.

Here's a couple of photos of the handset. Honestly, the pictures don't do it justice. It's so smooth that I'm concerned even about using Novus 2 on it! Really it just needs some polish with UV protection and maybe wax or something. I suppose Novus 1 would be good but it's expensive. Any suggestions? I have a car parts shop near me, they have a lot of waxes and polishes and the like. Don't want to waste my Novus 2 where it's not needed as that is also expensive.

Barry.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on February 13, 2017, 03:05:21 PM
That handset looks really good. I'm always worried about sanding or chelical smoothing because it basically involves removing some material and my concern would be loss of definition. But I have to say you seem to have got the balance just right with this. If the photos are anything to go by I definitely wouldn't be using anything even slightly abrasive any further. I don't know if there is any form of wax out there with a UV blocker in it. Maybe some kind of non-abrasive car wax would do something? I think I'd probably be tempted to just leave it though. In my experience topaz yellow is one of the better colours for keeping it's original shade. And even if it does fade it will probably take another 40 years! One question about this process though... Does it work better on the sides of the object that are in direct sight of the soaked paper towel or does it work evenly all round?

Regarding the crack repair... I wonder what would happen if you superglued a crack on the inside then did the 'vapour polishing'? Would the vapours move and redistribute enough of the surface plastic to make the crack vanish on the outside in the same way they make scratches disapear? Any dirt in the crack might mean it would still show though.

Andy.


Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on February 13, 2017, 04:09:30 PM
Hello Andy,
I may invest in some Novus 1 after all, well see.
I was careful sanding the handset to do each side of the centre line at a time and not sand on top of the line if you see what I mean. Seems to have worked. I also used small pieces of wet-and-dry, either an 8th or 16th of a sheet, something like that.

Regarding evenness, yes, it is even over the whole object, despite one side of the container having no paper on it so I could see inside. From what I've found it seems best to soak the paper towels quite a bit and expose the part for a short time, 15-20 minutes. Definitely worked best with the paper towel on top as well and with the object a couple of inches from the top. It's all trial and error I suppose. Who knows, I may have just been lucky with this phone and not be able to repeat it. Hope not.

Anyway, off for an early night.

Barry.

Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: WEBellSystemChristian on February 13, 2017, 10:15:48 PM
Actually, chemical polishing involves very little material being removed, most of it is reused and reformed on the surface. Sanding does outright involve removing plastic, but it's more controlled, especially compared to Acetone.

Looks great so far, keep it up! ;)
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: TelePlay on February 16, 2017, 08:24:07 PM
Quote from: WEBellSystemChristian on February 06, 2017, 10:03:34 PM
I'll address the most recent issue first. I've found that bubbles formed in Acetone 'pools' are very easily repairable. Simply put a drop of pure Acetone on the patch of bubbles, and 'blot' it out with your fingertip until the bubbles disappear, then let dry and sand.

Another way to "melt" plastic from the inside into a gouge or crack on the outside without having the bubble issue is to "slice" off a thin piece of plastic about the size of the small area to be filled, place the slice in the depression, put a drop of pure acetone on the slice in the gouge (just enough to cover the slice and fill the gouge - may be a partial drop), wait for 10 to 15 seconds (the acetone should not evaporate in that short period of time) and then take a flat metal item (a thin stainless steel ruler about a half inch wide and 6" long works well) and force it down on top of the slice to both force it into the gouge and to flatten the surface a bit. If it is a deep gouge and will require several slices, use something sort of round to press the slice into the below surface level gouge.

Let dry at least a half hour and sand flat.

Use a second and 3rd slice if the depression still exists. When enough plastic has been press-melted into the depression, the final piece will end up being higher than the surrounding surface, easily seen when sanding the patch.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on May 10, 2017, 01:15:17 PM
It's been a while but I thought I should post some pictures of the finished restoration. The acetone smoothing came out really well and so I just finished it off with some light Novus 2 all over. It needed a line cord and so I decided to buy a matchine yellow one along with a new handset cord. They are a very good colour match.

I also did an ivory phone the same way and it also came out really well. The grey one however, not so much. Did several attempts resanding in between but could never get the same finish, don't know why. I sold the grey one so it doesn't matter now. I only bought it to experiment on as it was very cheap. Yellow one is a keeper though! I also like that it had never been back for refurbishment, no stickers on the bottom.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on May 10, 2017, 01:35:51 PM
That's looking really good. I've taken inspiration from your work and taken delivery of some acetone. The first thing I've used it for is making a start on repairing a grey 741 that turned up smashed to bits by the couriers (AGAIN!  >:( )

I glued the broken pieces back together with acetone, then smudged aling the cracks with acetone on a small artists brush on the inside and outside. Then filled the small holes with liquid acetone and now I've started sanding.

Photos to follow later.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on May 10, 2017, 03:57:35 PM
Look forward to seeing how you get on with it Andy. Hope you get as good results.

I've also got a blue 746 with a bit broken off the front edge. I started to sand it and glued a piece of blister-pack plastic behind the break, just haven't got round to doing any more to it. I have a spare blanking button that I can use as donor plastic but still not sure the best way to do it. If there was a way of melting the plastic to fill the gap similar to a hot glue gun that would be ideal. The bubble problem when disolving in acetone is a pain.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on May 11, 2017, 02:47:41 PM
I've done a bit more work on the grey 741 today. The reason I'm having to do this is thanks to a VERY unhelpful e-bay seller, who I suspect may have broken the phone purposely in the hope I'd send it back because it didn't fetch a very high price. I contacted them and asked them to provide a replacement case so I could still leave good feedback, but they said they wouldn't do that and wanted the phone back to sell for parts (knowing full-well the dial alone would fetch more than the £12.50 I paid for the whole thing. So I called their bluff, kept it and just left them very bad feedback. ;)

So I could either buy a new case (about £15 from Britphone here in the UK) or rebuild the old one. I decided to go with the rebuild because it keeps the phone more original and also because I wanted to try the acetone plastic rebuilding technique. Overall I'm quite impressed so far.

I did things a bit differently to what I've seen mentioned in some of the other posts here, so I'll go through my technique just for the record...

First I got all the bits together. There were 3 or 4 main pieces and a lot of tiny bits about the same as a grain of rice. The tiny bits I could hardly picked up, so I disolved those in acetone to use later.

Having got all the big bits together I first had a dry run at assembling them. Unfortunately I found I had one piece missing. Thinking i would have to recreate that piece out of liquified plastic, I first stuck all the other pieces in position around the gap. I've seen others mentiuon doing this with super glue, but I remembered making plastic model lits using 'plastic weld' (MEK) in the past. I reasoned that acetone brushed onto the edge of the ABS pieces should work in a similar way to MEK, so using a fairly stiff bristled artists brush I brushed the edges with acetone and stuck the pieces back together (photo2). This left very visible cracks and a few places where the tiny bits of plastic had chipped off.

Next I brushed acetone over the cracks on the back, liquifying the inner surface around the cracks and making sure the plastic was effectively welded back together. The name of the game here is to move some plastic from the right of the crack to the left and some from the left to the right, effectively smoothing over the cracks on the inside.

I then turned the case back over and tried to smooth over the cracks on the outside. But because there were some small parts missing I needed to add some plastic. This is where the liquified stuff I had in a glass jar came in. It hadn't all completely disolved, so I got some of the bits that had now become like putty on the end of my brush and stippled them onto the surface where the holes were. As the acetone began to evaporate I brushed over the surface then rubbed it with my finger to make it as smooth as possible. Better to make the repair a little raised than too low, so overdo rather than under do the added plastic here.

When this was dry I started sanding, first with very coarse paper and then down to about 800 grit. This still left quite a few scratches. Next I put some acetone on a lint-free rag and rubbed it very quickly over the surface, keeping moving at speed so the rag didn't have time to stick to the plastic. This gave a sort of silk finish and removed any deep scratches still in place. Follow this with a light sanding again with about 00 grit. (photo3)

This was the stage where I finally found the missing piece hiding under a bell gong! So I added the missing piece, brushed across the cracks as above, sanded again, filled any small indentations still visible, lightly sanded again, then rubbed over with acetone on the rag as above. next came a final sanding again with 800 grit and a polish using T-Cut. It's not shiny, but I think it's close enough given I'm gpoing to try the acetone vapour process of polishing later. However before that I need to sand down the rest of the case enough to remove the fading which these grey phones suffer from quite badly.

Photo 4 is as far as I've got today. It shows the completed side of the phone prior to final overall sanding and vapour polishing. I'll add more as I progress.

The issue of bubbles in the liquified plastic hardly happened. Just one area had noticable bubbles. All I did was add a bit more liquid plastic to the surface and stippled it on using the stiff artists brush, which burst the bubbles and added a bit more plastic on top. The area was then lightly sanded just to smooth it off. I think stippling is the technique to use.

The finish is not perfect yet, but I think it's a good start. A few months ago I'd have thrown a broken case like this in the bin. Now I'm delighted to have what appears to be a pretty good method for repairs.

Andy.

Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: TelePlay on May 11, 2017, 03:58:49 PM
Quote from: andy1702 on May 11, 2017, 02:47:41 PM
When this was dry I started sanding, first with very coarse paper and then down to about 800 grit. This still left quite a few scratches. Next I put some acetone on a lint-free rag and rubbed it very quickly over the surface, keeping moving at speed so the rag didn't have time to stick to the plastic. This gave a sort of silk finish and removed any deep scratches still in place. Follow this with a light sanding again with about 00 grit.

Andy,

Very nice work and an addition to knowledge base of this type of restoration work.

One thing you may want to try now or in the future is mixing acetone with denatured alcohol to adjust the cutting power of the acetone when smoothing or "polishing" the plastic. The acetone evaporates first leaving just the alcohol to evaporate. The acetone does its work will being carried by the alcohol which has some but limited affect, compared to acetone, on the plastic surface.

I've been using 25% acetone in denatured alcohol for some time now and find it really gets rid of sandpaper marks quickly. You can up the percentage of alcohol to whatever works best for you. If you are going to do this, start with 25% and increase it until you get a cutting solution you like, that works well be does not cause the sticking/marking problems. I've found that different housing react differenly to the mixture so determine a good mix for each before using it on the outside. With 25% acetone, you can press the cloth hard on the plastic and rub until near dry. WEBellSystemChristian does this quite well - it's where I got my start in mixing cutters. And just 100% DA alone makes for a good last polish before going to Novus 2 or whatever you use to polish.

Post pictures when all done. You did some great work there.

Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: TelePlay on May 11, 2017, 04:29:35 PM
Quote from: royalbox on February 13, 2017, 04:09:30 PM
I may invest in some Novus 1 after all, well see.

I missed this when first posted, just caught it today. Novus 1 is just a mild surface cleaner which I think was intended to clean off any of the working components of Novus 3 and Novus 2. It doesn't polish, just cleans up the surface like window cleaner on a dirty window.

According to its MSDS, Novus 1 (https://www.acplasticsinc.com/media/documents/MSDS_NovusCleaner1.pdf) is simply 1-5% Isopropyl Alcohol in distilled water. You can make your own by adding 10 ml of 70% store bought Isoproply Alcohol (about $2.30 a pint) to 140 ml of distilled water ($1 a gallon) resulting in 150 ml of 5% Isopropyl Alcohol, 150 ml of Novus 1 equivalent.

Or 20 ml of 70% Isopropyl to 280 ml of water to get 300 ml of Novus 1 equivalent, a life time supply for less than a dime.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: royalbox on May 12, 2017, 04:11:05 AM
John, thanks for that info, is that really all that's in novus 1? That's suprising. glad I didn't buy any after all.

Andy, great job on that repair. Look forward to seeing the final result. Makes my blue phone damage look trivial in comparison except I don't have the original piece.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: unbeldi on May 12, 2017, 09:47:07 AM
Quote from: royalbox on May 12, 2017, 04:11:05 AM
John, thanks for that info, is that really all that's in novus 1? That's suprising. glad I didn't buy any after all.

Andy, great job on that repair. Look forward to seeing the final result. Makes my blue phone damage look trivial in comparison except I don't have the original piece.

I remember having received Novus 1 together with the other grades as a package deal, not really paying extra for it.  Novus 1 is not a polishing agent as such, but it does provide extra sheen when applied as a final step, and acts more or less as a cleaning agent to remove any remaining debris from the surface. I have used it with special lint free final polishing/cleaning cloth.  When bought as part of a kit, it came in a spray bottle that produces a very fine mist, perfect for the application.  But such spray bottles can of course be bought separately too, and many medicinal sprays come in such spray bottles too, which I have saved for this and similar purposes.

Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on May 12, 2017, 03:52:52 PM
Quote from: royalbox on May 12, 2017, 04:11:05 AM
Andy, great job on that repair. Look forward to seeing the final result. Makes my blue phone damage look trivial in comparison except I don't have the original piece.

I think not having the original pieces would make it a much longer process. I'm not sure I'd fancy trying to rebuild a completely missing piece out of liquified plastic. I was very pleased to find that last bit I can tell you!

I've still got some work to do though because if you look at the back edge of the case (bottom as it's laid down in the photos) you'll see quite a lot of it is chipped away. I'm just psyching myself up to tackle that bit.  ;D
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: andy1702 on May 26, 2017, 01:11:59 PM
Just a quick update on my GPO741 case restoration. You'll have noticed in the last photo there were some 'nibbles' around the bottom edge. I've now liquified some plastic in acetone, let quite a bit of the acetone evaporate off and then used the resulting paste to rebuild the edge of the case before sanding, rubbing over with acetone and finally rubbing with methylated spirits and buffing.

It's not perfect. I can see some of the joins in places where the replaced plastic is still a bit low. I guess I could add more plastic, but I'm going to leave it at that for now and get the phone back together and into use. I might re-visit the restoration to get it a bit closer to perfect in the future. I think this proves the concept though.

Andy.
Title: Re: UK GPO 746 Topaz Yellow Telephone Restoration
Post by: HarrySmith on May 26, 2017, 08:51:15 PM
Looks Good! Great job!