How to fill pinholes in varnish?


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Hi, I am varnishing a violin right now with oil varnish and I have some pinholes showing up on the head grain of the maple on the back and ribs. I am pretty much done with my color coats. Does anyone here know any successful way to fill them once the varnish is all on?

Thanks for any help.

Reuben

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Maybe sanding and another coat of varnish? (or is it on bottom layers?)

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I do not think it's the best solution, but I'll post it anyway, maybe it's useful for someone someday. I saw this recipe a while back and saved it in my files, never tried it but seems interesting.

From Kelly, A. Ashmun, The Expert Wood Finisher - 1915

Pitting on Varnishing on the Piano. - This may be remedied by rubbing it over with a hard wax polish.

Make a wax by melting together 2 oz. (57 g.) Carnauba wax, 2 oz. (57 g.) Japan Wax or White Beeswax will do, and 2 oz. (57 g.) ceresin wax.

Place all in a pot and melt by placing the pot inside of another vessel containing hot water, which place on the stove.

When melted add enough kerosene oil to make a mass, when cool, about like petroleum jelly.

Test by placing some on a glass and letting it cool, and if becomes too hard upon cooling add a little kerosene.

Apply with a woolen pad, made by rolling a strip of woolen like tape.

It will be necessary to give it two or more applications, the idea being to fill the little pits in the varnish.

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I believe that a filler of some kind is needed. This is distinct from a sealer. Traditional woodworkers use a seal-fill-seal method of some sort.

Often, for funiture, only walnut, mahogany, and other open pore woods are filled. But one does not care how much varnish soaks into a piece of furniture. (Or they apply a "spit coat" of shellac as a sealer-filler)

The old argument about minerals comes from a need to fill the wood, in my opinion.

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Hi, I am varnishing a violin right now with oil varnish and I have some pinholes showing up on the head grain of the maple on the back and ribs. I am pretty much done with my color coats. Does anyone here know any successful way to fill them once the varnish is all on?

Thanks for any help.

Reuben

You might want to research 'why' you got pinholes. Normally you get the opposite of pimples from dust specs and nits, .. etc static attraction maybe? It might be the solvents you used to clean the surface prior to varnishing or the solvents you are using in your varnish. There was a thread a while back on pinholes in varnish.

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Pin holes are not ussualy afatal defect as several others pointed out they are often seen on good mviolins and don't really detract from their apearance. If you really dont like them then make sure to seal and or fill the wood before your actual varnish (color) coats go on. Lots of ways to do this have been mentioned in previous threads on this forum

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Hi, I am varnishing a violin right now with oil varnish and I have some pinholes showing up on the head grain of the maple on the back and ribs. I am pretty much done with my color coats. Does anyone here know any successful way to fill them once the varnish is all on?

Thanks for any help.

Reuben

Reuben,

Are these holes which correspond to pore openings in the wood or are they actually flaws in the film?

Joe

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There are 3 primary reasons for this problem

1.As stated by Lyndon, introduction of air from application, generally caused by a dry brush or rapid brush stroking, or a thick viscosity varnish can do this when stipple patting application is done.

This may be fixed by lightly abrading and thinly re-coating as suggested by Carlo, I do not recommended wax on a violin, excluding a light paraffin rubbing oil

There is also a possibility that the holes are small enough that they will disappear when you finish the finish by rubbing it out.

2. Fisheye or finish separation, this can be caused by surface tension issues related to the binding stability of the varnish itself and how it relates and interacts with the coat that it is being applied to, related to adhesion.

3.Outgassing, as the varnishes have solvents, if a coat is over coated with another coat of finish with a similar vehicle base, say oil with oil....AND the under coat is not 100% dry, you will trap solvents under the coat you apply. The wet varnish will resolvent {leech into pores} then skin over, thus trapping solvent in pores. Once skinned over, the solvents will want to escape{like mini hot air balloons} and thus show as pinholes, particularly in open wood pores {as stated by Joe}...RECOATING IS NOT! the fix UNTIL ALL SOLVENT HAVE EVAPORATED!... meaning nothing but time will allow the finish to dry enough to re-coat.

Again, many of these problems will go away with final rub down.

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Reuben,

Are these holes which correspond to pore openings in the wood or are they actually flaws in the film?

Joe

Joe i was reading part of an interesting article the other day about colour varnishes and `vortex` effect caused by outgassing of volatiles (and then forming pin holes) which it said was also responsible for some of the clumping of pigment particles in varnish films. I didnt have access to the full article so didnt come to any conclusions.

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jezzupe,

All true...if the issue is film failure. Often these "pinholes" are related to the varnish dropping down into the open pores of the wood.

As on the Lady Blunt as Melvin noted.

on we go,

Joe

Yes, the "deep seep" I think it's somehow related to "the larger the waist band the deeper the quick sand"

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If the old masters used a ground to properly seal the pores, how did the coloured varnish end up showing pin holes along the flames in so many cases ?

Ben as i mentioned in a previous post ,a vortex effect where volatiles leave the varnish when drying ,leaving behind a small hole. Completely seperate process than sinking into pores. Not all varnish will sink into pores, its all to do with surface tension and the speed your varnish drys,as well as how thick or thin the varnish is.

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