I have been French polishing with the traditional method of a cotton wad with broadcloth cover (a”tampon”), lubricated with a little mineral oil. When I polish with the last coat of shellac, before “sprtiting off” that is, lightly buffing with a pad with mostly alcohol and very little shellac, to remove surface oil, the finish has a good mirror shine. A few hours later, when I am about ready to do the last step (spiriting off) it has become hazy or cloudy. Not opaque, just dull. If I re-apply a thin film of shellac over it, the gloss returns, but if I use any oil it will become dull again.
How much time should elapse detween the last coat of shellac applied with oil on the pad, and the final removal of any residual oil? I have tried paraffin oil instead of mineral oil with the same problem. Any advice appreciated.
Jay
Replies
Jay, you might check out this link [http://www.milburnguitars.com/frenchpolish.html] for good information on french polishing. It is very detailed with the' hows', 'whats' and 'whys' and has a FAQ section. You may get some insight for your problem. I think you may be using too much material on the mouse and spiriting too soon, trapping gas, but there are many other things that could be to blame.
Beat it to fit / Paint it to match
First thing I'd suggest is to use naptha for spiriting off instead of the traditional technique. If you get a little too much naptha you just wipe it off, unlike what happens with too much alcohol. Not at all sure this is the problem. Could you have a humidity problem?
I think I am waiting too long between sessions (due to life and work and kids etc...) and the excess oil that comes to the surface is sort of congealing. I may try the naptha. Is this something you have actually done and have experience with?
Also, I am having trouble getting up against the edge of the panel on frame and panel doors, with the pad. I have trie dto fold over a narrow cone, but there is still athin line that is unpolished. Since it is winter, this should be less evident toward the more humid months. Any suggestions ther? I did apply oil and a coat of shellac before assembly, but didn't French polish until after asssembly.
Jay
Yes, I have used the naptha successfully, but I didn't invent the technique. I read about it, probably in Bob Flexner's Understanding Wood Finishing.
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