Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Well I sure enough was thinking of the epoxy.

The sealant seems like an RTV material.  I might end up doing that, but this is for a friend, and I'd like to do it more the original way, since he is trying to restore it.  If I cannot, well, then I cannot. 

So far, I have used a material that is too thin, because I had it. It nearly worked.  I've been looking on McMaster-carr to see if I can come up with a better combination of thickness, durometer (hardness) and temperature range.

The initial issue I have is not being sure if there was a one-piece gasket, which is what I seem to recall from back before he started repairing it.  That would be my first choice if that was how it was originally made.   

It might have had two pieces, one at each end, that sealed the glass tube hole and also sealed the screws.

Despite two comments in videos that seem to show just a seal at each end of the tube, that's not how we seem to recall the system on it when he started, which was almost surely the original seal system, since he has owned it since it was new.   It would be nice if he had not lost the pieces of the original, obviously.

I'm trying to get the real info, and holding the RTV solution in reserve if we cannot get it done any other way that follows the original method.

There is always the possibility that the original method was a molded rubber piece that varied in thickness in different areas for the best seal.   That is very possible, and is a different problem entirely.   They made enough of these things to get whatever they wanted made the way they wanted it.

Might have had a "bead" or "button" around where the glass went through, and be thinner elsewhere, don't know.  That particular design could mean the dimples were opposite, with the "button" between them, so that they squeezed the rubber against the glass.

A lot of stuff I do not know, and would like to.