Author Topic: UK GPO 746 Topaz Yellow Telephone Restoration  (Read 4217 times)

Online twocvbloke

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #45 on: February 12, 2017, 05:53:44 AM »
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

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

Offline royalbox

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #46 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.

Offline andy1702

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #47 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.
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Offline royalbox

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #48 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.
« Last Edit: February 13, 2017, 11:47:38 AM by royalbox »

Offline andy1702

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #49 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.


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Offline royalbox

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #50 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.


Offline WEBellSystemChristian

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #51 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! ;)
Christian Petterson

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Offline TelePlay

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #52 on: February 16, 2017, 08:24:07 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.
            John . . .

              

Offline royalbox

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #53 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.
« Last Edit: May 10, 2017, 01:20:33 PM by royalbox »

Offline andy1702

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #54 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.
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Offline royalbox

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #55 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.

Offline andy1702

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #56 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.

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Offline TelePlay

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #57 on: May 11, 2017, 03:58:49 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.

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Offline TelePlay

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #58 on: May 11, 2017, 04:29:35 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 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.
            John . . .

              

Offline royalbox

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Re: UK GPO 746 Topaz Yellow Telephone Restoration
« Reply #59 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.