Classic Rotary Phones Forum

Telephone Identification, Repair & Restoration => Telephone Restoration Projects and Techniques => Bakelite Repair & Polishing => Topic started by: FABphones on February 10, 2019, 02:12:22 PM

Title: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 10, 2019, 02:12:22 PM
Sorting through the spares boxes with a view to starting a totally different project, the corroded cradle on this 232 body caught my eye. Once I had spotted it I couldn't leave it be, so it came out of the box and building a GPO 232 King Pyramid from spares became my next project. Putting together a King Pyramid has been on my to do list for a while.

I thought I would share this build with you so those who have never worked on a GPO 232 can follow the process of taking apart, tidying up, and putting back together.

The first job was tackling the corrosion, which had taken hold well. The plunger had seized, no movement whatsoever. I liberally applied WD40 to the plunger and screws and left them to soak awhile. Later, after carefully scraping away at the corrosion, the screw heads began to appear.

The plunger is removed from the inside by removing a metal clip. It took a bit of time as not much room to move in there, but it eventually came out ok. As I had sprayed WD40 on the plunger shaft at the same time as the screw heads, by gently 'wiggling' the centre top of the plunger it came free. Once out, I had access to the two corroded cradle screws. They took a bit of persuasion but they freed up so the cradle could be removed. Both parts came away from the body without damage. The next job was to remove the build up of corrosion.

I then removed everything from inside the phone, putting the too modern handset and line cables into a spares box. These will be replaced by original woven cords (also from a spares box).

A couple of loose screws fell out, no idea as yet where/if they belong in the phone.

The body and cradle parts are all marked 'PL' (Plessey). I found a 1945 164 handset (I do have rather a lot of spares), also marked PL, which will match in nicely with the other parts of the phone. I found a #10 dial (guess where...), which will need a bit of tidying up but is right for this phone.

The cradle, plunger and body of the phone have received an initial clean with 000 wire wool and Brasso. The cradle screws have been left to sit overnight in a puddle of WD40.

And with that I lost the good natural light of the day and my attention was needed elsewhere...

Photos of progress so far:



Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 10, 2019, 02:14:37 PM
You will notice on the photo below, the body of this phone has a nasty long crack on a corner.

Tomorrow I will be putting my experimenting hat on as I attempt, for the first time, a repair using resin and pigment. Wish me luck!  :)
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: Owain on February 10, 2019, 02:34:13 PM
Quote from: FABphones on February 10, 2019, 02:12:22 PM
A couple of loose screws fell out, no idea as yet where/if they belong in the phone.

Mounting brackets for the  Coil Induction No. 27?
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 10, 2019, 02:41:04 PM
 ;D I noticed that too after adding the photo and wondered if someone would spot they were already off... No, I started to remove the coil then remembered I hadn't done a photo first.

The two (mismatched) screws remain a mystery...  :)
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: HarrySmith on February 10, 2019, 02:44:48 PM
Thanks for posting the detailed progress, this will be interesting to watch. I am surprised those cradle screws came out, that was a lot of corrosion. I thought maybe the entire phone got wet at some point, maybe with salt water but the inside does not appear to have that much corrosion on any parts. This is a good example of why you never throw anything away, you never know what you might need in the future.
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 11, 2019, 01:33:44 PM
A quick update on the handset, with pics. Before and after it's clean with 000/Brasso.

GPO 164, marked PL and dated 1945. I got the Spitcup separately from my spares but I may change it if I can find a closer match, this one not quite right. Later.

Closeup pic of the cradle screws. The corrosion is lifting, they are spending another night in their WD40 puddle.
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: Doug Rose on February 11, 2019, 02:38:34 PM
CJ....wire brush on a drill will help those screws shed the corrosion and shine them up....Doug
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 11, 2019, 02:51:32 PM
Quote from: Doug Rose on February 11, 2019, 02:38:34 PM
CJ....wire brush on a drill will help those screws shed the corrosion and shine them up....Doug

:) I was wondering how to remove the corrosion from between the threads without chewing them up. The screws are tiny so I'll see what Dremel type attachment I have that isn't too fierce.
Thanks. :)
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: HarrySmith on February 11, 2019, 02:58:06 PM
I usually throw all the screws and small metal bits into a tumbler. A few hours in there and they come out looking brand new.

I have some pictures here of hardware after tumbling:

http://www.classicrotaryphones.com/forum/index.php?topic=17268.msg181861#msg181861
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 11, 2019, 03:06:31 PM
Quote from: HarrySmith on February 11, 2019, 02:58:06 PM
I usually throw all the screws and small metal bits into a tumbler. A few hours in there and they come out looking brand new.

:) I like the sound of that.

ETA: Just seen your pics... Shiny!  Now I want one, but yikes... super expensive.  :(



Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 19, 2019, 02:25:29 PM
Quote from: Doug Rose on February 11, 2019, 02:38:34 PM
....wire brush on a drill will help those screws shed the corrosion and shine them up....Doug

These were next put into a anti-calc cleaning fluid and left to soak a further couple of nights, then had the wire brush treatment on a Dremel type mini-tool.  Big thanks to Doug for that tip.  :)

I had no idea what metal was under all of that corrosion.
One shown 'before' and the other 'after'.
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 19, 2019, 03:01:00 PM
The crack on the body of this phone is long - from the bottom corner to about 1/2 cm from the top.

In order to (hopefully) get a better bond for the resin I used a mini-tool to grind the inside and roughen up the surface a little. I experimented with a few different bits as some barely scratched the surface of the Bakelite.

Although the Bakelite was cleaned I didn't shine any of it up first as I didn't want to add anything to the surface that might prevent a good adhesion.

Photo shows the damage midway through the prepping, prior to adding the resin. I've shown it through a magnifying glass. I like to work whenever possible using a convex lens in order to try and get a good close look at what I am working with.

After taking this photo I finished the prep, gently prised open the break and added the coloured resin, working from the inside. This was then held tightly together leaving the resin to harden (cable ties are good for this). No photos as yet of that stage - a little pigment goes a long way. Literally. Hands, working area, fabric, everywhere and onto anything. I didn't dare reach for the camera.

The longer I can leave the resin before sanding and working on it any further, the better.  :)
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 19, 2019, 04:16:33 PM
Whilst I was searching through my Spitcup spares I took a few photos for comparison.
Photos show five #15 Spitcups.

On the photo of two Spitcups, they are both marked S (Siemens) but carry different codes.

On the photo of three, the one on the left is the PL (Plessey) Spitcup I chose for this project, the centre Spitcup has no manufacturer mark (and the holes are slightly smaller), and the one on the right is made by Indian Telephone Industries.

Manufacturer ident codes:
http://telephonesuk.co.uk/ident_codes.htm
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 22, 2019, 02:56:53 PM
I'm not happy with the set of my resin, I suspect I added too much pigment, so today I removed and reapplied.

Meanwhile, I need to find three matching cords: handset, line, and bell to phone.
There's a matching set in there somewhere...

This truly is a project made from spares.  :)
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 24, 2019, 01:31:32 PM
Leaving the new application of resin on the phone body to harden for a few days, I made a start repairing the Spitcup, which was missing a piece (you can see this on the photo of three Spitcups on page one of this thread). I reverted to my preferred epoxy putty for this as it hardens nicely and has a good strength. Just to throw in a twist I experimented by adding black pigment to further darken the 'shade' of black.

Here it is after a light sanding. Am very pleased with this little repair. On the photo I have pointed it out with an arrow, photo a bit dark. Lighting for photos is high on my agenda!  :)
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 26, 2019, 01:52:44 PM
Ok... Mixed results with the resin repair on the body damage. Photo below shows what it looks like mid sand.

Today I began the buffing process and as you would expect, once a shine is on the surface the repair shows more than I would have liked.
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: andy1702 on February 26, 2019, 02:52:39 PM
Now you've sanded it the repaired crack still looks a bit low to me. Is that right? I think I'd try putting more resin in and leaving it a bit proud of the surface, then sand the excess off. The other option would be to give it a coat of filling primer then paint the whole phone. Painting isn't ideal, but as the case was damaged anyway I'd view it as a necessary repair if that's the only way to get rid of the crack. You could always paint it red, then you could sell it on fleabay and buy about 10 more black ones with the profit!  ;D

Seriously though... I tried a similar repair using epoxy resin with powdered charcoal mixed with it for pigment. The problem I had was bubbles in the epoxy which only came to light once I started sanding it.

Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 26, 2019, 04:04:15 PM
An update on progress so far:

Mixed results on this first try, I definitely need more practice. The resin didn't quite give a good enough (in my opinion) 'invisible' repair. It may be too low, but I'm not sure that's totally it. I think the break was a smidge out of alignment too. Judging by the corrosion, it had been left like that quite some time before it came to me. The plunger is also out of alignment so I need to address that as well before it can be reassembled.

Another thing I discovered, is working with such tiny quantities of resin makes it tricky getting the pigment quantity correct (it would be much simpler to mix up a vat of the stuff ;D). I used jewellers scales but even so, one drop of pigment weighs more than one might think.

I have also experimented by adding additional resin to the exterior, but it does not adhere well enough without heavy sanding (I try to keep sanding of Bakelite to a minimum due to its construction. Usually I don't sand it at all). Internally I would have also added fibre-glass sheeting for extra strength but I never had any. Noted for next time.

I don't paint Bakelite as it is not to my liking but if the final result isn't great no harm done, an undamaged body will turn up at some point and I can replace it. Meantime I've got some practice in and shared the result, good or bad. And regardless of how it turns out, I have learnt from this and will move forward with that knowledge.  :)

As the #10 dial I initially selected has now been earmarked for another project, I used this #12 dial. It needed a little attention (black gloss paint spillage to one side, fingerwheel didn't return correctly). Cleaned, oiled, now whirring nicely.

Photo of dial rear numbering, and photo of repaired area now buffed, with dial in place. Damage shows up differently according to the angle viewed and the light on it.

Still lots of work left to do on this phone.


Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 27, 2019, 10:30:11 AM
Today has been a good day.  :D

Firstly I managed to get the plunger working again. Seized into position, over time it had distorted out of shape and once freed wouldn't fit correctly into it's cradle.

Thread for the fix here:
http://www.classicrotaryphones.com/forum/index.php?topic=22014

Then I continued sanding the break and got that looking a bit better too.

And finally I removed the paint from the Bakelite junction box that I will be using for the line cord. Gave it the shiny treatment and it shone up beautifully. Very pleased with that - shown in photo with no lights turned on, and it's not wet.     ...Sunglasses on  8)
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: andy1702 on February 28, 2019, 03:26:03 PM
Have you tried black boot polish on that crack? It needs to be the traditional thick waxy stuff in a little round tin. Apply liberally, wipe off the excess with a cloth then buff with another cloth to a shine. If the crack is a bit low the polish should fill it in.

I have some bakelite repairs to do myself, but my problem isn't cracks, it's missing chunks. I've been putting it off for ages, prefering to work on ABS cases where I've got a bit of a system going.
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on February 28, 2019, 04:21:26 PM
Quote from: andy1702 on February 28, 2019, 03:26:03 PM
Have you tried black boot polish on that crack? It needs to be the traditional thick waxy stuff in a little round tin. Apply liberally, wipe off the excess with a cloth then buff with another cloth to a shine. If the crack is a bit low the polish should fill it in.

Thanks for the suggestion. Out of curiosity I had already tried that a few days ago. Ineffective, but knowing what doesn't work is almost as good as knowing what will.

The damage repair isn't quite what it appears to be in the photo, there is no gap to force anything into. It's a fraction of a mm height difference between the two levels. I'm cautiously working on the difference with micromesh, although sanding Bakelite isn't something I like to do.

The correct way to continue with this would be to remove all resin and start over, however I doubt I could now get a good bond inside that fracture without opening it up and grinding it. And if I tried that, in this instance it would probably do more harm than good.

*Chunks are a doddle in comparison!  :)



Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: andy1702 on March 01, 2019, 11:29:39 AM
I'm curious what resin you're using? The colour match and finish looks really good. Like you said, it's the height difference that's making the joint show.

The way I understand it, bakelite is a sawdust filler suspended in some type of resin. It's certainly grainy under the surface. My assumption is the resin flows round the particles of filler to reach where the bakelite interfaces with the mold. So what I'm wondering is if you can take the surface off a relatively large area and re-flow a thin layer of resin over it? I've not tried this, it's just an idea in my head.
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on March 03, 2019, 01:35:22 PM
Here it is folks. Finished.

The damage to the corner is stable and strengthened from the inside. Not as invisible as I would have liked, but I've learnt a lot from this first resin project.

These many discarded parts are now a complete telephone again, pieces out of spares boxes that I have accumulated over time, from all areas of the UK. Odds and ends, from the spitcup to the dialcard circlip.

It threw me a few curveballs but I got there in the end.  :)
Title: Re: Building from Spares: GPO 232 King Pyramid
Post by: FABphones on March 05, 2019, 02:13:13 AM
Thanks guys, you are very kind.

As I get more experienced with these resins I may come back to this one, but at least I managed to find all PL (Plessey) parts so it's about as 'parts matched' as these come.  :)