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alcohol and restoring bad shellac finishes?

Posted: Sat Feb 04, 2012 8:44 am
by FloridaClay
Very often I find old machines in the wild with shellac finishes that have bubbled up and gotten discolored and a surface feel like course sandpaper because of having been stored in an attic or shed or furnace room where they were exposed to a lot of heat. I know that alcohol dissolves shellac and have read that using alcohol to remove the shellac can serve to preserve the original stain underneath so that you have a base for a more authentic restoration.

Has anybody tried this, and if so, how well did it work for you?

Can you use alcohol to soften the shellac sufficiently so that it reflows, or do you just get a sticky glop so that you have to take everything off down to the stain?

Clay

Re: alcohol and restoring bad shellac finishes?

Posted: Sat Feb 04, 2012 9:26 am
by Retrograde
when I first read the title of this thread I thought it was some sort of public service announcement :coffee:

re-amalgamation is what most people call the process. It works best to re-flow the existing shellac with some fresh shellac added to the denatured alcohol. The results are so-so, not exactly the factory look. This of course depends on the skill of the restorer.

Re: alcohol and restoring bad shellac finishes?

Posted: Sat Feb 04, 2012 9:56 am
by FloridaClay
Retrograde wrote:when I first read the title of this thread I thought it was some sort of public service announcement
Well, I will admit that I have had a few resotration sessions that have made me think about turning to drink! ;)

Clay

Re: alcohol and restoring bad shellac finishes?

Posted: Sat Feb 04, 2012 11:50 am
by gramophoneshane
I remember reading on the OTVMMB that there's a commercial product available in USA, to re-amalgamate this type of finish but because it isn't sold here I didn't take much notice of the brand name.
I've had good & bad results when attempting to reflow a badly alligatored finish with alcohol, & I think a lot depends on hoe deep the original polish is.
Thinner finishes seem to restore better than a thick finish, & I think this is because the alcohol is absorbed & evaporates too quickly on a thick finish, so it doesn't get the chance to level the polish properly, and using too much alcohol, or attempting to repeat the process often gives you an uneven patchy look.

I know when I've fixed a crazed finish, applying some raw linseed oil to the rag before the alcohol is a big help because it prevents the alcohol from drying out as quickly, giving you more time to work & repair the shellac, so perhaps adding a few drops of linseed oil to the alcohol & mixing well before applying it to a deep, heavily alligatored finish might give better results than alcohol alone.
Unfortunately, I haven't had a chance to experiment with this myself because since I thought of it, I haven't had anything to try it on, but I'm pretty confident it will improve my chances of success.

Re: alcohol and restoring bad shellac finishes?

Posted: Sat Feb 04, 2012 1:22 pm
by Henry
Gramo, is that boiled linseed or raw linseed? We can get both over here, maybe you can as well. Mmm, wonder if it matters which kind one uses for this purpose?

Re: alcohol and restoring bad shellac finishes?

Posted: Sun Feb 05, 2012 11:43 pm
by Covah
Shellac darkens and turns black and crusty with age. You can soften the crust but it will dissolve back into the finish, leaving blotches. The crust needs to be mechanically removed. I used 330 grit sandpaper lubricated with mineral oil or wood stain or Danish oil to remove the crust. Then buff with Howard's "Restore-A-Shine" compound.

Re: alcohol and restoring bad shellac finishes?

Posted: Mon Feb 06, 2012 7:34 am
by FloridaClay
Thanks to all for the helpful information!

Clay

Re: alcohol and restoring bad shellac finishes?

Posted: Mon Feb 06, 2012 11:43 pm
by martinola
Hi Clay.
My take on re-amalgamation is that it's worth a try if you don't mind being patient and are willing to experiment. I just finished a re-amalgamation of my Standard Model D that was rather rough and had bad flaking on the lid, back and crank side. The thing is that simply re-flowing a trashed finish isn't usually enough. I've had to add coat after coat of clear shellac in order to "level out" the finish. There's a lot of time that goes into touch-up color matching, filling in low spots, sanding and polishing. The result is essentially the original color and (I think) better than a re-finish.
Std D before side view
Std D before side view
Std D after side view
Std D after side view
Std D wide after front
Std D wide after front
Below are some shots of an earlier re-amalgamation/restoration of my Standard Model C ICS machine. My main goal on this one was to save the decal.
Std C finish and decal before
Std C finish and decal before
Std C decal after
Std C decal after
Std C wide after
Std C wide after
Anyhow, whatever you do decide to do; good luck! :)

- Martin

Re: alcohol and restoring bad shellac finishes?

Posted: Tue Feb 07, 2012 6:18 am
by FloridaClay
Very handsome results Martin!

Clay

Re: alcohol and restoring bad shellac finishes?

Posted: Tue Feb 07, 2012 9:22 am
by alang
Great job Martin!
May I ask what you used to fix the missing parts of the Edison decal?
Thanks
Andreas