Back Plate Restoration - Diaphone 138607

[Spencer541]

Hi all,
So like a kid with a new toy I'm (we) are excited to start restoring this diaphone. The plan is to get it working again and have it look nice. I call it 138607 cause of the number stamped in the top plate, I assume it was a unique serial number?
Wanted to start with the back plate and ask for some advise of what others have tried and worked. The outside seems to be in pretty good shape however the inside shows some rust. Plus there's this raised ring with 19 holes in it. Was that part of the back plate mold? Or is it a gasket of some sort? That ring is deteriorating badly, will this cause the diaphone not to work?
Anyway - What is the best way to remove the paint from the outside? Sandblasting, a paint remover?
What should I do about the inside, sandblast it, steel wool, leave it alone?
Are there other options that are available?
Thanks for you help in advance
Spence

[Jim]

Spence:
The ring you mention and show in your nice photos is the remnant of the back gasket. It used to go all the way to the edge, but being squeezed between the throat and cover has preserved only that part.
Actually the gasket is the only important part of the back cover assembly.
The holes are impressions from the machining holes in the throat.
The corrosion is a problem only in that care should be taken to be sure that no flakes of the rust get in to the working parts.
It is likely that the rust covers most of the steel/iron parts, inside and out.
Most people have found that the throat is fairly easily pressed out of the housing. The rust may make it more difficult, but also more necessary to remove flaky debris.
Make note of the position of the throat before you start, but it is probably flush with the housing.
Wire brushing and a coat of oil should do the job.
Here are some pics of what to look forward to:
https://gamewelldiaphone.com/wp-content ... 21d&34f21d
Paint remover on the outside is the place to start, reserving sand-blasting for later if necessary.
In every step, make sure that the close tolerance of the piston and throat is not compromised.
I envy you guys the work you are doing.

[Spencer541]

Thank you so much Jim for the reply.
That's good news about that ring just being a left over gasket as that can be replaced with ease. I was really worried those remnants was some kind of irreplaceable molding in the steel/iron on the back of plate that was rusting away. That's a really odd gasket material.

As for the Housing and Motor/Speaking chamber I was going to start a whole other thread for that but you're saying those come part?? I mean I can physically take out the Motor/Speaking chamber? You're kidding, does anybody have a picture of that? I can't get mine to budge. Can I put penetrating oil on it? It's not secured in there by any means right?

As for the close tolerance of the piston and throat, that does scare me a little as the screen that was located in "Air Inlet Gauze and Frame Section" was completely blown apart and full of debris. I ASSUME the gauze filled up with debris and the air pressure finally blew it apart. Hope that the piston wasn't damaged to much.
We shall see. I'm going to start on that back plate right away.
BTW I've been using the part terminology found on the Gamewell Diaphone cleaning video posted by Sonic Fields

[Jim]

Here is some discussion on your question:
https://gamewelldiaphone.com/forums/vie ... hroat#p389

[Jim]

That link was from a search. This one might be better:
https://gamewelldiaphone.com/forums/vie ... out+throat

Also please note that the grandson mentioned above is now 14 and in high school.

Depending on your experience, we may separate one or both of our TOOTers.

Jim

[Jim]

Another try at a cleaner link:

https://gamewelldiaphone.com/forums/vie ... p?f=2&t=65

Note that the airraidsirens refs are no longer available. Unless maybe Adam can tell us where.