Official Luthiers Forum!

Can any of the oil finishes be used over dewaxed shellac.

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Mike McNerney

I have put TruOil over shellac. Worked just fine and still in good shape about 15 years later.

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Steve Smith
"Music is what feelings sound like"

Me too, no problem yet.

B

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My memory is so good, sometimes I remember things that never happened.

I've used several different oil varnishes over a seal coat of dewaxed shellac without any problems whatsoever. In fact, the only issue I've had with any varnish was over rosewood that had not first been been sealed with shellac. It simply wouldn't dry until I scraped it off, sealed with shellac, and reapplied.

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George :-)

Yup I think shellac is the universal sealer. I would guess that dewaxed, as you mentioned, is key though. I've been using an oil varnish for the past 3 years and always seal with shellac, so far so good.

thanks to all I'm doing it.

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Mike McNerney

Depends on what kind of oil finish. Varnishes are probably OK so long as you dewax the shellac and make sure to lightly scuff it... Don't want the varnish to peel back off.

With plain oil finishes - I would not apply over shellac as they will just leave a sticky mess...

The term 'varnish' is so loosely used it can lead to all kinds of problems. I'm not sure even calling it an 'oil' varnish helps. The best answer to all these kinds of questions is... make test panels. Of course sometimes these things don't appear as problems for some time.

Shellac is used as a sealer to reduce/control the amount of oil that is adsorbed. A wash coat of 1/2 lb cut will have a little effect. Remember Minwax stains are dilute linseed oil and pigment and a little dye.

At some point the oil will not soak in and must be wiped off

I use a siamese red shellac that has some wax in it . Then finish with tru oil or cabinetmakers varnish or laquer. I am using med grade ca glue for finishing open pored woods before final finishing and after sealing with shellac, and experimenting with 2 part epoxy pore filler which I find dificult to master

FWIW, these are the specific "varnishes" I have used successfully over a seal coat of dewaxed shellac, all of which are holding up just fine after 10+ years:

Pratt & Lambert #38
Ace Hardware Great Finishes (solvent-based)
Tru-Oil

Yeah, when trying any material, process, or tool for the first time, testing on scrap is always a good idea.

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George :-)

"Shellac sticks to everything, and everything sticks to shellac"

I was taught this in the 70's by an old furniture repair guy. I have 40 year old furniture projects around the house with a couple of coats of padded de-waxed shellac, covered in everything from spar varnish (polishes beautifully), to alkyd varnish, to water based varnish, urethanes too, and have never had a failure.

Ed