finishing question..

[Gold Rock]

I need some help from our finishing experts. As shellac is alchohol based, does it make a suitable overcoat for wood that's been treated with linseed oil? Shellac is my go-to standard for almost everything interior (love the stuff; low toxicity, fast drying, easy cleanup, petroleum free, and looks great), but I have some trim that I prepped with linseed oil thinking I'd finish it with a paste wax finish (also a stunning, low luster finish) and I've, uh, changed my mind. I'd rather use a shellac finish, mostly for consistancy's sake. Turns out, I think, that buffed wax would inappropriately stand out aside the rest of the cabinetry. I have the time to make sure the oil is reasonably dry. Used a healthy dose of Jap dryer in the cut. What does the opinion say?

[Meli]

I'm a big shellac fan myself.
I've refinished timber that has either a natural oiliness to it or that has had oil spilt on it no problem.
however I dont think I've ever tried on something deliberatly coated with linseed.

Try giveing a small area a good rub down with turps, the brush a bit of shellac on and see what happens, you can always wash it off again if it doesn't take

[Gold Rock]

Try giveing a small area a good rub down with turps,

Certainly a good suggestion. I'd also have to keep an eye that the turps rubdown didn't "mottle" the oil base.

[David G]

If your boiled linseed oil is dry enough - and, as you know, it takes a while - you can got right over it with a dewaxed shellac (like Zinsser SealCoat). Any shellac (waxed or dewaxed, and any tone, will work over that).

[ILikeRust]

Shellac over linseed oil works just fine. And provides much better protection of the wood than just paste wax. Much easier to keep the wood clean, and shellac is a very repairable finish (unlike polyurethane).

[Bob Smalser]

While I like it too, the down side of shellac is that it wears easily and doesn't hold up as well as varnish in applications where handling is involved...like drawer fronts, banister rails and the like. It also waterspots easily, and deteriorates more rapidly in UV that even interior varnishes. The good news is that it's renewable....you can abrade then topcoat the existing finish to renew it. Google "French Polishing" and teach yourself how if you haven't already.

I routinely wetsand using linseed as a lubricant to fill pores in open-grain woods like walnut and mahogany with sanding slurry, then topcoat with either shellac, wiping varnish, interior varnish or spar depending on the application, and don't have any problems with finish longevity because of the linseed. It just takes a week or so to dry thoroughly. I prefer the resulting color to those commercial stain-filler concoctions that cloud the resulting finish with (literally) mud used as a filler. I generally use raw linseed and add a half cup of Japan Drier per gallon, and also sometimes a dollop of pine tar for color.

[Gold Rock]

Marvelous guys. It's just so tough to fault shellac. You're on the mark Bob, shellac is really only an "indoor" product. All remarks re: wear, et. al. are true in my experience as well. Hey Dave, give me the lowdown on "waxed" v.s. "dewaxed". I've never heard of that aspect. At work and mostly at home, I use only Zinsser "Bullseye" shellac. I try to stick with the 'amber', though I sometimes go with the 'clear' since my local suppliers are sometimes out. I have a few pounds of flakes that I've yet to dissolve, but I don't recall any admonishments about wax or not when I bought them.

[Bob Smalser]

The trick to prevent 3M5200 from gluing wood together you only really want to seal, is to prime, paint and then wax the faying surfaces before bedding in 5200 and fastening. Not a bad idea actually, as the synthetic goo outlives traditional, oil-based bedding compounds severalfold over.

Wax interferes with bonding, and for finishes that will need to be renewed regularly like drawer fronts and table tops, dewaxed shellac is a (slightly) better choice.

I have a rifle stock I made in 1977 that I finished in shellac at a client's request. It's due back in a few days and I'll take some photos of it. While the finish crazing from UV is minor (only because the rifle didn't see much use), it wouldn't be crazed at all if I had used a wiping varnish or spar.

[Jay Greer]

Shellac will work with oil which, is the second major component for French polishing. Shellac can be applied with a pad using a drop of linseed oil as a rubbing lubricant. Padding will give a better finish that a brush will and will build as each new coat bonds to the old one. In the process of French polish, pumice is used as an added filler and abrassive. The pumice erodes the wood and combines with the wood dust and shellac to fill the grain. Although labor intensive, historicaly, it gives an unequaled finish. Unfortunaly French polish is easily damaged by moisure such as the ring made by damp glass set on the surface.
Jay

[Eddiebou]

Although this has nothing to do with your original question. I just want to say that I've been a user of shellac for years, I've always considered it an interior finish. This came up on a thread a while back. So I decided to test it for myself. I took a scrap of mahogany and a disposable brush and applied about 3 coats of shellac (about 8 months old) and tossed it into a tub of water outside of my shop. I expected to see the finish simply melt away or turn white or something. To my astonishment, 2 months later, it looks just as good as it did when I first did it. I intentionally left 1 surface uncovered to see if the effect of water getting under the shellac would loosen it from the surface. The water sure soaked into the unsealed wood, it's black, but I see no effects whatsoever. This doesn't mean I would trust it indefinately on its own, but I am surprised by these results.