varnish

[goose 2]

Many of the higher end builders and companies use varnish on their best mandilins. I have noted that some finishes are "oil varnish" and others are "spirit varnish". What is the difference, if any, between the two? Is one more durable or easier to apply, is there a difference in tone or are all varnish finishes essentially the same? Anybody out there have a clue??

[Michael Lewis]

Spirit varnish is shellac flakes dissolved in alcohol (spirits) with maybe some other resins or gums dissolved in it too. Oil varnish is generally based on a drying oil or a polymerizing oil. There are many variations of these varnishes, but the system that is currently held in the highest regard is an oil varnish topped with a thin application of French polish, which is spirit varnish. The shellac in the spirit varnish presents a harder surface finish to protect the softer oil varnish while the oil varnish hardens over the years.

[BigJoe]

There is a tonal difference from one finish to the other. If you use an oil varnish only, it will be soft for quite a while and is very easy to mess up. If you apply a thin application of oil varnish with a thin coat of french polish over that it gives a nice warm tone (Gibson MM). It is not quite as delicate as the oil varnish only. If you use spirit varnish it will not be quite as warm a tone as the combination. More of a mix between the tones of varnish/french polish and lacquer. Not quite as round a tone but still very nice. Spirit varnish dries much faster and is much harder and not quite as delicate as the other two. All give a nice tone but my personal preference is the oil varnish/ french polish method. It is a bit more time consuming and delicate than spirit varnish, but to me it is worth the extra effort. Hope this helps some.

[goose 2]

Thanks guys. Another question, what are the downsides of again french polishing on oil varnish finished mandolin several/many years after it was made? Is there an upside other than a cosmetic one which to me is not important?

[sunburst]

A correctly applied thin finish of any kind actually has a minimal effect on the sound of the instrument. Any differences from one correctly applied finish to another are very subtle indeed.

An oil varnish is so slow to harden, that it is very difficult to bring to a high gloss when it is relatively new. That's the real reason for shellacing or french polishing over the oil vqarnish, to bring it to a gloss without having to wait many months for the varnish itself to be hard enough to buff.

There's no real reason to french polish over an old oil varnish other than cosmetic reasons. If there was no shellac on top to start with, you can buff the varnish itself to a good gloss. If there is old shellac that is worn through in places, you can touch it up and restore it to looking new. It's harder to touch it up and keep it looking old.

[goose 2]

Thanks again.