spirit vs oil varnish

[tim noble]

I came upon a Loar thread from a few years back where Will Kimble stated-

"I have spent some time with one of the cremona F4s, I think it is from 1921. It is my opinion that it is an oil varnish finish similar to an F5, whereas the other F4s I have seen appear to be spirit varnish. I think these F4s sound unique".

As the owner of one of the 10 or so documented Cremona sunburst F4's - 71080 fon 11548- I'm curious if others have noted this. I believe that Loar F5s were oil varnish and that over time (1924) were over coated with french polish (spirit) and then a light coat of nitro and finally by 1925 full lacquer. I've had many Gibson mandolins from the early - mid 20th century and the manner in which the finish ages on the 1922 is very different than on earlier or later instruments. Were Loars the only instruments that got the oil while others a spirit varnish or later lacquer?
Tim

[Hendrik Ahrend]

You're probably aware of these threads; highly informative I think :
http://www.mandolincafe.com/forum/sh...ibson+Finishes
http://www.mandolincafe.com/forum/sh...ibson+Finishes

[tim noble]

Thanks for the links Henry. I do recall the the one with Steve Gs comments but the second link goes into additional details that are fascinating. It's so difficult assessing these finishes in photos. What is distinctive on my 22 F4 is the extremely fine crazing radiating mostly at the curvature of the plates (particularly on the back). This is almost identical to the patina on an early 1928 Martin 00018 I have. This guitar has a transitional finish where the back and sides are lacquer but the top is still oil varnish (according to a number of experts and my own research). I've had many years experience in finishes analysis starting with an MS at Penn emphasizing architectural conservation and have studied the finish under balanced light with an Olympus Zoom scope from 10 - 50X. Darn if I can see more than a stain coat and a single coat of what appears to be an oil varnish. If a subsequent coat with sufficient solvent was applied properly, meaning before the first hardened, it should melt and blend with the first and become imperceivable. A top coat of spirit may be visible as it likely would sit on the surface rather than blend in. The finish is extremely thin with the grain of the spruce showing through the finish and it appears softer than a 90 year old french polish. There is no flaking that can occur on harder finishes and I don't have the nerve to remove a tiny sample to observe under my polarized light microscope.

Before grad school I studied under Arthur Falardeau who had been Wurlitzer's chief violin restorer from the 1920s to 1960s at the Philadelphia shop and have all his books, tools and documents. The formulas they used for varnish are so complicated and slow curing that no production shop would consider using it. He grafted new necks onto original scrolls , installed bass bars, etc. on many dozens of Cremona instruments and told me that the restoration/modernizing process often lasted more than a year due to the cure time for the finish work. If any one has a finish sample from the early 20s (only need less than a pencil eraser sized sample) I'd be happy to observe it with the PLM. With the ability to view at 500+X and the incredible shallow depth of field I should be able to see layering. However, a sealer coat over the stain likely would not be included with the sample because if the finish flaked off it would likely cleave at that layer. Fun academic exercise but with retirement at the end of the year my lab will be disposed of in a year or two.
Tim

[Oliver A.]

This is almost identical to the patina on an early 1928 Martin 00018 I have. This guitar has a transitional finish where the back and sides are lacquer but the top is still oil varnish (according to a number of experts and my own research).
Tim

I've been under the impression that pre-lacquer Martins were completely french polished. I recall seeing a photo somewhere of a row of Martin employees sitting at stations by a row of windows who were all french polishing guitars. It's been a long time since I saw that photo and I don't recall where I saw it but are you certain that before switching to lacquer, Martin used an oil varnish?

[tim noble]

Some experts on the Unofficial Martin Guitar Forum stated that in researching the authentic series and particularly their new thin finish (VTS I think) that Martin found formulas from the period. I inquired with Dick Boak and he agreed. Earlier than the 1920s I think they were french polished and Martin experimented with different finishes throughout the 1920s until they settled on full lacquer in 1929. Sounds pretty similar to what Gibson was doing, just a few years later. I'm trying to learn what may have taken have place to replicate on future builds. I built 2 F5s in 1976 and 77 under the guidance of Roger Siminoff and supplied very old violin tops and backs I got from my mentor and he put them through his Gibson pattern machine. As the first instruments I built from scratch (after having restored many over the previous years) they have certain flaws but sound pretty good. Both were lacquered as were the 7 subsequent guitars. I've studied and worked on a 1929 and an early 1930 OM28s, still have a 33 OM18 and a 38 00028 and the finishes are wonderful and thin but the 28 00018 and 22 F4 have the most beautiful finishes I've encountered. After reading a number of builder threads on the cafe, I'm getting settled on Epiphanes Clear Gloss Varnish with a french polish top coat as the most similar to Loar period high end finishes. I'd just like to verify that pesky french polish top coat or at least determine just how some have visually of scientifically verified it.
Tim

[Oliver A.]

OK that sounds quite possible. Martin is way better than most at record keeping. The photo I saw could well have been taken before 1920.
I'll just tell you my personal experience with varnish. I have used several different tung oil based varnishes and even straight polymerized tung oil. (admittedly not Epiphane) I always come back to spirit varnish. I have found that oil varnish remains too flexible and acts like a wet blanket on the tone of an instrument. It may be good 50+ years from now as it cures but right now I am convinced that spirit varnish is the most acoustically transparent finish there is. I have also tried many recipes, some of my own and some well known violin maker's recipes and I keep coming back to straight, high quality, mixed fresh, shellac applied in as thin a layer as practical. That's what the french polishing excels at. I try very hard to separate myth and lore from what really is by careful observation (listening) and note taking and this is where my experience has lead me.

I think tung oil and tung oil based varnishes are fantastic finishes but not for mandolins.

Anyway, that's been my experience and there is nothing like finding out for yourself. Maybe you will come to different conclusions but only by doing will you really know.

Take care,
Oliver

[Jim Hilburn]

From someone who isn't all that studied in the subject, I would submit that at least in the violin world the "wet blanket" effect was, to a degree part of the recipe as a violin can be quite shrill without its finish. They were looking for that dark rich tone.

[Oliver A.]

Yes, while I haven't made a violin, I could understand that for violins, whose strings are bowed (applying constant energy) rather than plucked, oil varnish may well be a better choice. I know what I have experienced and at least one other very famous mandolin maker seems to have come to the same conclusion.

[Jim Hilburn]

Yeah, I went to a workshop with that mandolin builder on how he does it.

[tim noble]

There is a lot that is unknown about the finishes that were used in the 1920s and 30s and the more I research it the less I'm sure. Most seem to agree that Gibson used spirit varnish up to 1921 and began experimenting with a spirit (shellac-based) sealer, oil intermediate and spirit top coat. Its likely that the oil varnish contained different additives than violin varnish resulting in a harder faster curing varnish. Was the Loar period varnish soft? Apparently not or some/many owners/restorers/builders would have commented on fingerprints, imbedded dust, etc. that would invariably have occurred in the first years of use if it took years to reasonably cure. Heat or moisture can soften most finishes so only instruments not subjected to adverse conditions would need to be observed. My 22 is pretty hard with no signs but who knows. Some modern builders and restorers use pure shellac, either sprayed, brushed or padded, while others use just oil or a combination of the two.

What I have noticed is that the finish on my 28 00018 and 22 F4 are extremely similar in hardness, patina and resistance to wear and visually nearly identical. What seems to make sense is that in this transition from spirit to nitro they began with a proven sealer of shellac, used a fairly thin hard fast drying oil coat often associated with violin finishing (ff holes were associated with the viol tradition as was oil) and top coated with shellac which they knew would dry hard and fast and protect the oil while it fully cured over the years to come.

From my experience with restoring antique furniture, oil varnish can be as hard as nitro and can become brittle and flake off which I don't see with spirit. It probably comes down the the formula used in any recipe.
Tim

[mandroid]

I have a 22 A4, and a 22 plain A .. after sweat damaging the back finish, of the Brown A ,
I Put a ToneGard on the A4, to protect it from Me.

[Oliver A.]

Its likely that the oil varnish contained different additives than violin varnish resulting in a harder faster curing varnish. Was the Loar period varnish soft? Apparently not or some/many owners/restorers/builders would have commented on fingerprints, imbedded dust, etc. that would invariably have occurred in the first years of use if it took years to reasonably cure.

Tim, you probably know more about the tecnical/chemical properties of "varnish" than I do. When I said 'soft', I didn't mean that you could imprint it with your finger. This stuff is tough. You can use it on floors and I let it cure for 30 days in lots of indirect sunlight before french polishing. What I mean by soft is that the varnish film seems to have a greater flexibility than cured shellac. A rough analogy would be rubber vs plastic.The rubber like properties seem to causes a damping effect on the wood. These mandolins that I finished with oil under french polish were not horribly affected, they sounded somewhat similar to lacquered mandolins. They were just not as open and resonant sounding as the mandolins with the all shellac finish.

I was actually hoping that that the oil under french polish would be the ticket. Since the oil can be brushed directly onto the stained sunburst without disturbing the color at all, It would have made my life much easier in that I could have completely avoided any need for a spray booth but I have to go with what is best in terms of sound. With an all spirit varnish finish, I have to spray a couple of light sealer coats of shellac to lock in and protect the color coats before french polishing but my goal is to go with what actually works best for sound and not what is expedient (Gibson?).