Gilfillan Prototype Set

[miniman82]

So here's how I decided to repair the flyback, whose wax tire had decided to fall off in chunks over the years.


First a before shot, all dirty and nasty. This flyback is unique just like the one in the 21-CT-55, because it has one of the filament windings for the rectifiers right there on the tire. There are also 2 other filament strings, wrapped around the ferrite core. I think it had to be done this way, because there simply wasn't room elsewhere.



Ah, that's better! All cleaned up with q-tips, Goof Off and alcohol, took about 2 hours.



Amazing it came out that clean, there was actually a nice looking transformer under it all.



Next I removed the bad sections of remaining wax and squared them off, using a soldering tool to melt it which was pretty smelly. Then I built a sort of cardboard trough around the remaining good section of wax tire, sealing the edges where it met the transformer with bits of wax. I poured 2-part silicone into this to make a mold.



Looks like it came out good, but how well had I captured the original profile? Pour in some wax to make a test casting! This is monocrystalline wax donated by John Yurkon, it matched the melt point and hardness of the original stuff pretty close but not the color.



Looks like a match!



Next step, position the mold carefully around the windings and pour:



The result looks pretty good.



Only thing is the original section of wax was slightly angled, and that transferred to the mold. That meant the new wax was slightly misaligned, as you can see where it meets the original wax. It's not bad enough to matter, I think this new tire will work just fine.

[NoPegs]

Originally Posted by miniman82

I poured 2-part silicone into this to make a mold.

Can you enlighten me on the specifics of the two-part silicone you used to do this? I have a whole list of things it would help me with.

[miniman82]

It was a kit from the hobby store specifically for making molds, it just happened to be a 2-part silicone. The name of it is alumilite quick set RTV silicone rubber, worked really good and the hot wax didn't phase it at all.