MIMF

I seem to have it a ceiling on my final french polish gloss and it is falling short of where I'd like it to be. The surfaces are well prepared and filled. The FP has been fully bodied up, leveled and glazed. When I look close at the surface, however, it appears like the FP surface is not perfectly level, it has tiny irregularities. Looking at the edges reflections in the gloss, the reflections are not sharp. I have tried sanding the surface down with 2000 grit w/d and reglaze with FP, but the irregularities come back. My sense is I am dragging these tiny irregularities into the finish as I polish. I've tried different covers on the pad including old cotton tee shirts and old cotton pillow case. Tried varying concentrations of shellac & alcohol. Shellac is freshly mixed using LMII shellac flakes and 190 proof grain alcohol. I use walnut oil but have also used olive oil with similar results.

I also find that when I do achieve what I think is a high gloss surface it seems to fade away after a week or so, making me think what I really had was a nice polished film of oil which then evaporates or otherwise looses gloss.

Mequires #7 glazing polish seems to help, but it too seems temporary. What I am getting is adequate, but would really like to hit this out of the park. How do I get that drop dead high gloss w/ FP?

CB

Before you try abrasives, are you letting the finish cure thoroughly? Usually takes a week (two is better) before it's hard enough to buff out. The "fade away after a week or so" sounds to me like you're actually seeing a film of oil (which is cloudy) seeping up from a curing finish.

Bill Hicklin wrote:Before you try abrasives, are you letting the finish cure thoroughly? Usually takes a week (two is better) before it's hard enough to buff out.

No, not waiting more than overnight, but I am not trying to buff it out, I'm trying to apply final high gloss layers of shellac. I'm using 2000 grit sandpaper wet to level the surface on the theory that I'll never get a truly level final layer unless what is underneath is truly level. Yet, even sanded level, I seem to be reintroducing irregularities again. After the final leveling, I am using only with the grain strokes, not circular.

I know some allow the shellac to harden up well and then polish it with abrasives and rubbing compounds to a high polish as one would do with nitro but that is not what I have been trying to do, at least not yet.

Bill Hicklin wrote:The "fade away after a week or so" sounds to me like you're actually seeing a film of oil (which is cloudy) seeping up from a curing finish.

If it is a new layer of oil seeping up from the finish after the fact, it does not seem to be removable like oil or feel oily.

In looking closely at a recently finished guitar right now, it appears that most of the irregularities appear to be small straight lines parallel to the grain. I'm guessing these are very small ridges of shellac being left by the pad cover.

CB

In looking closely at a recently finished guitar right now, it appears that most of the irregularities appear to be small straight lines parallel to the grain. I'm guessing these are very small ridges of shellac being left by the pad cover.

Sure sounds that way. In that case, your glazing perhaps either uses a fad that starts too wet, or too much pressure. Also- are you "working the fad dry?" Glazing for me means continuing to work the surface in long, straight strokes until the fad no longer feels cold against the back of my hand, in other words all the alcohol is gone.

I've also found it effective to save the final 'glazing' for a fully-cured surface- just hang it up for a couple of weeks so that the shellac is good and hard and you're only re-softening the tiniest little bit of finish.

Mind you, even a 'perfect' FP job- that ideal I've never fully attained - leaves a softer gloss (which I prefer) to the plasticky gloss of power-polished nitro. If you want a finish like a factory Martin, then you'll have to get out the buffing wheel.

When Glazing, you should be using about a 1 lb cut of shellac, no oil, and straight, glide on, glide off strokes with the muneca. You should be using a material that does not stretch. T-shirt material is not particularly good for glazing. Something like cotton muslin is much better, or the premium material - linen. Abrasives should be eliminated from the process as much as possible. The muneca should be close to dry when you start the glazing strokes. Pad off on a piece of paper towel or something till it doesn't make much of a spot. If, after a few glazing sessions, you aren't getting a gloss, try a couple of more body sessions to increase the build, then try glazing again. You can get a good gloss, and you don't even need the Meguire's.

Waddy Thomson wrote:When Glazing, you should be using about a 1 lb cut of shellac, no oil, and straight, glide on, glide off strokes with the muneca. You should be using a material that does not stretch. T-shirt material is not particularly good for glazing. Something like cotton muslin is much better, or the premium material - linen. Abrasives should be eliminated from the process as much as possible. The muneca should be close to dry when you start the glazing strokes. Pad off on a piece of paper towel or something till it doesn't make much of a spot. If, after a few glazing sessions, you aren't getting a gloss, try a couple of more body sessions to increase the build, then try glazing again. You can get a good gloss, and you don't even need the Meguire's.

Thanks, that all makes sense. A nearly dry muneca in particular makes a lot of sense in relation to what I perceive as my problem. I'm glad to hear linen is good for covers, my wife offered some that looked good, but I thought it had to be cotton. Some followup questions if I may.....

• Regards the 1lb cut shellac and no oil, are you using any additional alcohol on the muneca or just the 1# shellac?
• If no oil, do you not have any trouble with the muneca sticking? Is the nearly dry muneca the trick to this?
• Is it important to let the base harden up before glazing? If not using oil, I should think so.
• Do you put multiple glazing coats on in a session?
• Why eliminate the abrasives? Sounds like you don't sand at all? I do find it takes a couple coats to get the muneca to glide well after sanding, even with the finest paper.
• Any experience in apply shellac over Meguires? That is, now that I've applied Meguires, is it too late to try your ideas above.

Thanks again

I don't claim to be any kind of expert, but my understanding is that French polished shellac, properly applied according to traditional methods, is an abrasive free process after pore filling with pumice. There are many variations on the process, however, and a lot of folks use abrasives in the process to make it work for them. I won't say I don't, because I have tried a number of different methods. I have found, though, that once I start bodying, I spirit off(also called stiffing off) after every body session beginning with the second one. Spiriting off is the leveling process to remove the swirls and the bit of oil that surfaces during the body sessions. When bodying, I use a 2 lb cut, and apply a couple of drops of that with a few drops of alcohol. Pad it into the muneca against my hand, then tap on a paper towel till I get only a slight mark. I use a tiny touch of Walnut Oil(less than a drop) on about every second or third time I add shellac and alcohol. When I spirit off after the body session I wait about 10 to 15 minutes then put about 4 or 5 drops of alcoho, pad against my hand, tap a couple of times on the towel and glide on and glide off with straight strokes with good pressure, but quick strokes, not slow ones. If you have used Meguire's, I'd spirit off before bodying or glazing again. I often spirit off before starting a new session after the guitar has sat over night, too, as oil tends to work it's way to the top when it sits like that, particularly if you use a bit too much.

I use little 2 - 4 oz bottles from US Plastics with the little pointy tops for my alcohol and shellac, as they are easy to apply a drop with, and cheap. When I'm finished bodying, I usually just look at the shellac in the bottle and add about enough alcohol to double the volume, probably, actually less than a 1 lb cut. When I refresh the muneca I do about the same as when I'm bodying, but with the lighter shellac, and no oil, ever. Glazing in my mind is much like spiriting off, except with shellac in the process. It levels as well as builds, though very slightly. Some folks say not to do more than 3 sessions a day(bodying or glazing). I have done more, without any negative outcome, but at some point, you realize that you are pushing around old shellac, if you try to do too much. It will get stickier and stickier, the more you do. At least that's my experience.

Don't know if that helps, but always think dry. A wet muneca takes off more shellac than it adds, I think. It's amazing how much faster it builds when you work dry.

Waddy, Thanks, that is all very helpful. I'll try again using your suggestion next chance I get.

An old trick, often quoted in handbooks, is to use some alcohol solution of "benjoin" (styrax in English?? do not ask me what origin) in the last glazing sessions. Super high gloss can be obtained but the resulting treatment is hardening a little less with time, I were told, than with usual plain alcohol. I knew a couple of makers who were doing that but I never did it myself. So, test on a varnished scrap before...

I believe you are talking about Benzoin not Benjoin. Benzoin comes from some of the Styrex family of plants. http://en.wikipedia.org/wiki/Styrax

Yes, Benjoin is the French for it. It was used mostly by cabinet makers. Less by instruments makers I guess. For my two successive Maestros, the first one used it for "exhibition instruments", the second never uses that trick.

Is the benjoin (benzion) used as a resin or a solvent? Is it benjoin + shellac or benjoin + alcohol?

It is a resin. Germond in his book called "l'ébéniste restaurateur" ( 1992, only in French I am afraid) recommends a solution with 4% benjoin (styrax) in weight, only for the last sessions of glazing. I am told some English speaking guys translate benjoin by benjamin.
He also says it hardens the standard shellac treatment, but I also heard the opposite <g>.
It smells great too. I could try that trick someday. It is not a difficult one.

Thanks

Hi there,
benzoin has been used for centuries in violin shops to give old instruments a final polish before sale. the practice is frowned upon a little now but it still goes on. the benzoin resin is disolved in alcohol with a little shellac. it is then applied quickly to the instrument, with the grain. I use it on all my instruments whether i've used my own oil varnish or shellac.
It smells so good they use it in chanel No.5.

Hi nikacons- welcome to the forum and thanks for the input. Please note that we require the use of real names here (first & last)- drop me or one of the moderators a PM and we can fix up your registration.

Where does one acquire walnut oil?

Stephen cowden wrote:Where does one acquire walnut oil?

Better grocery stores.

Depending on if you want the Walnut oil to become incorporated into the French polish or not, you should be aware of whether it has any added antioxidants or is contaminated with other, non-drying oils (frequently the same presses are used in the production of oils for different varieties, like olive or peanut, which are non-drying).

Some people claim that the use of a drying oil results in a harder surface, while others claim no benefit, or report that it results in witness lines where the oil is incorporated.

When you buy your oil, you can leave a drop of it on a piece of glass, and test to see if it dries. Pure, uncontaminated walnut oil will dry, but if it is contaminated with a non-drying oil or has added antioxidants (added to many health-food varieties for the health benefits and to give the product a longer shelf-life and to help prevent it going rancid), it will not dry, or at least, not completely.

If you wish to incorporate the oil, you should make sure that the oil you purchased will dry properly. If not, the French polish will never dry properly, and may peel up. I believe this will also cause an exaggeration of the witness line effect reported by some users.

If you don't wish for the oil to be incorporated, you will need to "spirit off" or "stiff" the polish, as you would normally do when using other oils like olive or mineral.

"If you don't wish for the oil to be incorporated, you will need to "spirit off" or "stiff" the polish, as you would normally do when using other oils like olive or mineral."

This applies even if you want the oil to be incorporated; there will always be a degree of seepage as the film cures.

Mind you, there's a big difference between using the occasional drop for lubrication, which really has no effect on the finish composition and can just as well be olive oil or whatever, and the John Greven approach of mixing in walnut oil to the tune of ~20% of the shellac solution.