Loar F5s, Oil or Spirit Varnish?

[Hendrik Ahrend]

Is there any agreement these days as to what kind of varnish the Loar F5s actually (or mostly) had? I mean in basic terms, oil or spirit varnish, whatever the actual recipe. I'm aware that Gibson tried different things on the Loars up to nitro-oversprays as early as 1924 (or even earlier, Darryl?). According to Charlie Derrington (RIP), the Loars had a french polish top coat on oil varnish. Stephen Gilchrist, however, who surely knows a bit about Loars, uses spirit varnish for his own mandolins and possibly on his Loar refins as well. Does any of you know more about this? Doesn't "french polish" just refer to the method of application?

Thanks a lot,
Henry

[fscotte]

Gibson only used frenchmen to apply the varnish.

[Hendrik Ahrend]

Gibson only used frenchmen to apply the varnish.

Oh, not from Poland?

[multidon]

French polish does indeed refer to a method of application but usually it is pure shellac dissolved in alcohol with a bit of oil for lubrication. When oil varnish is used in production instruments it is often applied as a top coat to protect the varnish when it isnt completely cured. A custom maker may have the luxury of being able to wait a month or two waiting for the varnish to cure but a factory needs to get instruments out the door so the French polish enables them to do that. Not ideal but it works. Many of course like the look that French polish over varnish gives. Its not as harsh a gloss as varnish. I have never heard of French polish over spirit varnish. I dont know for sure but I suspect the alcohol used to dissolve the shellac would adversely affect the spirit varnish. As for what was used on Loars I'll let the experts chime in on that but given the circumstances as cited above French polish over oil varnish would not surprise me.

[FL Dawg]

Isn't the alcohol the "spirit" and it simply evaporates after being applied?

[Tavy]

Isn't the alcohol the "spirit" and it simply evaporates after being applied?

Correct.

I would imagine that FP over spirit varnish would be fine - in fact they're basically the same thing applied in different ways - just more additives in spirit varnish, where as FP tends to be done with pure shellac in alcohol.

For example the "The French Polishers Manual" states:

"The ingredients of common varnish are nearly the similar to those of polish, but are somewhat different in their proportions, being forty ounces of shellac, four ounces of resin, five ounces of benzoin, two ounces each of sandarac and white resin, to the gallon of spirit."

The manual also gives a somewhat colorful description of application:

"The most experienced varnishers maintain that it is best to make a sleek ground with a rubberful of French polish, always before the application of spirit varnish; and that it is equally important to dry the rubber thoroughly, leaving no degree of unctuousness upon the tin superstratum, previous to laying on a coat of finishing varnish. They unanimously assert too that it is of utmost consequence in the production of a faultless gloss, to permit the last pellicle of polish to get an hours rest before it receives a coat of fine varnish, and also to let the coating of slake to "stand" for two hours prior to it's being finally smoothed with a damp rubber."

[HoGo]

Bask to OP. General consensus is that Loar era F models were oil varnished (some kind of standard hardware store varnish - likely phenolic resin + linseed oil based) and french polished on the top. French polish was used as it was simpler back then to get nice gloss with top coat of FP than polishing the oil varnish alone (they didn't have all those fine grades of sandpapers etc...). Reasoning that FP was used to cover uncured soft oil varnish is no good. That would be just asking for problems. Bridge would imprint drastically and the whole thing would be covered with finish cracks in few weeks (actually they are covered with web of tiny cracks because the FP layer is harder than underlaying varnish). Why Steve Gilchrist uses spririt varnish is question for him and I guess it allows him to produce them in such numbers and with less finish "surprises".
Spirit varnishes are typically used in repair situations even over original oil varnish as they are much easier to blend with just about any varnish and are reversible if one needs to remove the repair later...
To adress one more thing... French polish is name of method of application of shellac dissolved in alcohol. The shellac-alcohol qualifies as spirit varnish by definition and if applied by brush and polished with pumice it may look indisguishable from FP.