Re: Help with Gulbransen Unit-Pneumatics
By Larry Fisher
George writes:
> So far all I've been able to do with these "late-model" (1926)
> Gulbransen Unit-Pnematics is DESTROY THEM! The fixed board is very
> thin, maybe 3/16", and the old hide glue is incredible.
> Should I cook them longer? steam them? (Reblitz doesn't like
> moisture.)
A previous post suggested freezing the entire assembly as cold as you can find, preferably below zero. The hide glue become quite brittle, (along with everything else except the wood) and shatters quite nicely. Removing a pin block from an old upright taught me about the effects of hot vinegar and water on glue joints. I also added alcohol just before pouring the mixture on the glue joints but I got a feeling the alcohol simply vaporized with the heat and so did nothing to induce penetration. The hotter the mix the better it penetrates and being that it has vinegar, it should get hotter than 212 deg F (100 C) and really do a good job on softening the old glue. If you apply the mix from a squeeze bottle or eye dropper, or I believe it's called a pipette, the amount shouldn't amount to so much that damage occurs. I've been steaming pneumatics in a covered kettle for years now, and the minor warpage that occurs eventually flattens back out again by the time I reglue the pneumatics back on. The tier that the assembly is glued to will get some moisture on it as well, but once again should only be minor and being that it is much heftier in size and mass, it shouldn't warp at all. Allow everything to dry completely and recoat with shellac a few times to reseal the wood. Then recover and reglue. I've been regluing with PVC-E glue for the last couple of years, but some people like to stick with original materials as much as possible so they use hide glue.
There was quite a thread on Gulbransen's a while back. They can be quite a charming bit of work to rebuild. I hope it works well for you when you're finished. Good luck.
Lar
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(Message sent Fri 25 Oct 1996, 15:31:35 GMT, from time zone GMT-0800.) |
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