Oil varnish and french polish

[Cary Fagan]

I've read here that spirit varnish is easily damaged if alcohol is spilled on it. I've also read that French polishing an oil varnished instrument is to protect the soft varnish, especially in the first year as it hardens. French polish is done, I've read, with spirit varnish. Does that mean it is also easily damaged by alcohol? Is it also soft for a while?

Not that I plan to spill any drinks, but I've got a new mando coming and have never had a varnished. I'm happy to have it age and look used, but would like to avoid actually damaging the thing. Any advice would be helpful.
Thanks.

[Mark Franzke]

I don't have any experience with oil, but I really like French polished shellac. There are some good articles out there. Milburn Guitars has a very detailed one, and if you follow it carefully, you will get a perfectly smooth, hard finish. It does take practice. The first three I did had some flaws, the fourth one is nearly perfect. The next one should be perfect. I could spill my beer on it and it would be fine, unless I let it sit on there for awhile.

[Hans]

Yup, alcohol can damage spirit varnish/French polish. I believe that French polish was used over oil varnish cause oil varnish ghosts (applied coats don't meld with each other) when sanded. French polish was used to shine the instrument up. The longer the spirit finish is on the instrument, the less it is affected by #alcohol, however I don't think that it is ever impervious.

[F5G WIZ]

What I have discovered (the hard way) is that a fresh varnish finish is very tempermental when it comes to heat and humidity. #Until the finish hardens completely, heat and humidity can cause problems with the finish. #I would reccomend getting a tone gaurd to sheild the back of the mandolin from your body heat while playing. Just the heat from your body can cause finish problems. #I ended up getting what looked like very small checking marks everywhere my body touched the mandolin, IE where my arm was resting on the front and where the back was resting against my body while playing. #I was able to buff them out but they came back a bit after further playing. #Live and learn I guess. A tone gaurd and arm rest will help with this problem.

[HoGo]

French oplishing over oil varnish is always tricky. The oil varnish is typically softer and more flexible than shellac. Also the oil will be shrinking slowly for several months after application. Most violin makers would tell you you are crazy if you want to apply spirit varnish over oil. The outer layer should be more flexible and softer then the lower layer otherwise it behaves like thin ice on the water. The two layers contract differently witch changing temperature and the shellac can crack. Aggressive sweat is a killer of shellac or varnish too.
IMO some surface crazing on french polished over oil is inevitable in the life of the instument unless the oil varnish was super hard (Rock Hard Table top varnish comes to mind).
That is the price you pay for the looks and natural shine of the french polish.
Just my $.02

[Stephen Perry]

We see lots of violins with thin French polish over oil. Folks shining them up over the years. I've only seen the crazing a couple of times, and it worked right out with alcohol polishing.

The Milburn article is great! We normally use simply a pad of cotton, a little dab of shellac and benzoin, and a dab of oil. Patted out before the oil drop goes on. This leaves just a nice shine, good for maintenance. Certainly on a larger surface with the goal of building up a finish the more complex system would work much better. But for maintenance, almost nothing does very well. Keeps the shine, protects the underlying varnish, very very thin.

Although I like beat up dull oil varnish just fine.

[HoGo]

Most violinmakers use benzoin or other softer resins but most mandolin makers use straight shellac solution that can cause the problems. The softer resins can cause bridge sticking to finish under pressure on mandolins.

[Big Joe]

Just as all Varnish is not the same, not all French polish is the same. We make our own varnish and french polish. The two work quite well together for us with our formulation. They seemed to have worked for Gibson in the early 20's also.

Varnish/ shellac finishes are a bit more finicky than most lacquers. Spirit varnish will usually cure fastser and become harder much faster. We have experimented with some that are harder than lacquer. However, the varnish we use is not so hard and does take a while to cure. We use base coats of oil varnish then dry them in a UV booth. After they achieve a reasonable hardness we apply french polish over the top and then put them in the UV booth to dry. We, of course, level each coat with sand paper between coats. Our goal with french polish is not the shine. It is the harder top coat that will allow the instrument to be touched and used till the oil varnish completely cures. It also affects the tone and helps us achieve the tone we want (MM and DMM models only).

I would advise the following for care of a good varnish finish...particularly oil varnish/ french polish. First, if you must clean it with something other than a dry, very soft cotton cloth, then use a damp (not wet) soft cotton rag and clean the instrument with that. Ensure you dry it completely before putting it back in the case. Again, a very soft cotton rag. That should be enough for most cleaning. After it has cured, maybe a year down the road, you can use a product like Dave Harvey's Jubilee Polish. Only use it when absolutely needed and as little as needed to get the job done. DO NOT USE GUITAR POLISH!!! It will eat the finish on your mandolin.

When you play you can use a tone guard or place a diaper over the rim and back of the instrument when you play. This will keep sweat and body oils off the manodlin. That ais probably the worst thing you can expose it to. Some use the diaper draped over the front where your forearm hit also. I use and arm rest. The tone guard are not expensive compared to a finish repair, help the volume of the instrument, and keep it much safer than just hanging it next to your body. When your finish had hardened like a rock (and it will), then it is much harder to damage...though it can be done. Again, body oils and sweat are usually the biggest culprit. Next to that just ordinary dust. Dust is just like sandpaper if allowed to build up. Hope this information helps.

[F5G WIZ]

I've only seen the crazing a couple of times, and it worked right out with alcohol polishing.
Is this something that can be accomplished by your everyday run of the mill Mando owner or should it be accomplished by a pro luthier? What kind of alcohol is used for this procedure. I realize that all instruments eventually get marked up (distressed) but I'd like to keep it shiney for a while at least. She's still just a baby!

[Stephen Perry]

I would think that alcohol polishing isn't something your casual worker wants to do. It scares me!!! Essential to know exactly what finish you're dealing with.

Big Joe's description is dead on for what I see some violinmakers doing. That's what I do. I have 2 different varnishes, one reasonably hard, the other very soft and lush. Both look much better with a bit of shellac benzoin polish on them. That's our final step. And it does wear off - I generally rub the edges that are taking wear with the polish a little bit when things come back in for work.

In cleaning, the best thing might well be deionized water. I never remember to get it, but it is a super cleaner.

Something that is different from the mandolin world is the sanding bit. Violin people tend to like texture. I do. I just get the nubs down between coats and attempt to preserve the scraped texture. Not deep ribbing, just the nice fresh look.

Building up a polish finish ala Milburn is also quite different from just putting a layer of shiny hard over another finish.

[Yonkle]

Can someone explain what a "Oil Varnish" is?
I use shellac and alcohol (Spirit Varnish) so how do you make a oil varnish and apply? I wnat to get a finish on my mandolins like the photo on the left. Just looks like shiny wood. Lacquer and shellac look more like the one on the right, glass over wood. How can I do this?
Sorry they are not mandolin photos, but they are finish photos. JD

[Michael Lewis]

For a result sort of like the one on the left you can use oil varnish with a pad (small wad of cotton in a piece of cotton sheet 2 1/2" sq.), and rub it on in very thin coats. One coat a day if you make it thin enough so it drys overnight. Get the varnish from International Violin and use a bit of gum terpentine to thin it. Go over it once with the pad, make sure the varnish is thin and even, and hang it up to dry. The trick is to get it done well and right the first time and then keep your hands off while it drys.

The guide I use for this oil varnish is to firmly press my thumb into the finish for 20 seconds, if a print is left hang it back up to dry some more. Only apply more varnish over dry varnish. Otherwise it takes forever to cure and harden. Once it no longer takes prints you can scrub the surface with a pad, some pumice, and a little bit of oil. This is a simplistic overview of my oil varnish method, but it works and is the real deal.

As you use and play the instrument it will wear and polish where it is touched and rubbed. This cannot be helped, so if you want a dull finish you will have to perform periodic upkeep, otherwise it gets shiney in the wear areas.

[David Newton]

No one has yet to mention Tru-oil over shellac. I did my last mandolin with this, and found it quite nice. It's all about the preparation of the wood first.

[Yonkle]

I re-finished a cheap Kay guitar for a friend. I bought Deft semi gloss lacquer and kind of got this natural looking finish (ok to experiment on his guitar) just not on mandos. Anyway dod any of you who use lacquer ever use semi gloss or even satin? What do you think about it? Photos?
I always notice when I spray the very first very very light coat of shellac and the figure jumps out, the way it looks just then is what I'd like it too look like finished just not grainy.

[F5G WIZ]

I've used Deft on some wood carvings I have done. Boy does that stuff stink! But it dries fast.