Non-toxic wood stain
January 11, 2006 8:09 AM   Subscribe

What's the least toxic way to stain and seal wood?

I've got one of those bookcases from an unpainted furniture store, and I'd like to seal the wood against spills and make it look pretty, but I don't like the looks of the warnings on varnish and sealant cans. I've simply no need to introduce more carcinogens into my life, but I would like a nice sleek finish for my shelves.
posted by Sara Anne to Home & Garden (26 answers total)
I was in the same situation recently regarding some unfinished furniture and was very happy with chinawood oil (this oil also has another name which I forget). I just smoothed the wood a bit first with some steel wool. Easy and looks good with very little odor when applied. Maybe also look into tung oil, linseed, etc.
posted by exogenous at 8:13 AM on January 11, 2006

Get a water based stain and water based poly.
very little smell and easy cleanup. You may even be able to find a water based stain/poly combo, if you look hard enough.

water based stain

water based poly
posted by cosmicbandito at 8:16 AM on January 11, 2006

exogenous, I think tung oil == chinawood oil.

I second it, but find it has an unpleasant smell when drying, a little like rancid macadamias.
posted by scruss at 8:27 AM on January 11, 2006

Shellac is the safest sealant, among other things it is used as a coating on hard candies to stop them sticking together.

Strong coffee will stain pine pretty good to a kind of chocalate colour though I've found it to be kind of blotchy. If the bookcases are oak or other tannin containing wood you can fume them with ammonia or even vinigar to deepen the colour.
posted by Mitheral at 8:41 AM on January 11, 2006

The problem with tung and linseed oil is that unless you go to extra ordinary effort the stuff you buy will contain decidedly unfriendly metallic dryers.
posted by Mitheral at 8:44 AM on January 11, 2006

Earthborn are based in the UK but produce the most 'safe' and environmentally-friendly paints and varnishes around. They have a water-based varnish which you might be able to get hold of in the States. I've used their interior paints before and they're a dream to use.
posted by blag at 8:52 AM on January 11, 2006

Tung oil is natural, but it's hardly non-toxic. It's a potent irritant.
posted by ikkyu2 at 9:16 AM on January 11, 2006

you can get water based wax finishes, i believe. i think that's what i used years ago on some bookshelves. not sure it did much good, but then i'm not sure i've ever spilt anything on them. maybe wood is good enough all by itself?
posted by andrew cooke at 9:18 AM on January 11, 2006

If you use shellac, you have the added advantage of being able to tell your friends you painted it with an excretion of the female Coccus Lacca beetle, harvested from the bark of the trees where she deposits it to provide a sticky hold on the trunk, necessary during mating with the non-stick capable male.
posted by weapons-grade pandemonium at 9:20 AM on January 11, 2006

On the flip side, you could work in a well-ventilated area and get yourself a quality respirator mask. You can spend anywhere from $20 to $200 on something, but once you have it you should be golden for decades, so long as you can get new cartridges.

If you intend to live in society and deal with paints and cleaners you'd be better served investing in something like this. If nothing else, you'll almost certainly be faced with the prospect of paint fumes in the future.
posted by phearlez at 9:21 AM on January 11, 2006

Gah. I had no idea shellac was bug excretion. I guess like honey, right? Need to let that settle in a bit, and then go to the hardware store.
posted by Sara Anne at 9:29 AM on January 11, 2006

well, more like beeswax.
posted by rxrfrx at 9:31 AM on January 11, 2006

Oh, I should have added - part of why I suggest this is that I work pretty extensively with water-based stains for these things and for the first few dozen I was using the Minwax water-based sealant on them. However it was not at all durable against water, even after fully curing.

Since my process requires application of tile grout and subsequent (sometimes vigorous) removal with a damp cloth after the sealant phase, as well as requiring the sealant to help protect the wood against the grout at that point, this wasn't acceptable to me. So I've switched to their fast drying poly and found it very tolerant of water.

My stuff has to be tolerant of moisture because a lot of them get used in bathrooms and I don't want angry calls about warping. But I'd also be reluctant to use the water based sealant for any home furniture I was going to interact with so that I could clean it effectively with typical cleaners or a damp cloth. If you're working with a water-based stain you'll find that they just don't penetrate as well - I scrubbed the color off several of my mirrors in spots back in the early days when I was using the polycrylic. It might take longer for you to do it in a home setting but, if anything, that could be worse - more trouble to touch-up later.

I under no circumstances would put the polycrylic on a coffee or dining table. I have 0 faith it would protect against water marks.
posted by phearlez at 9:33 AM on January 11, 2006

Paints generally aren't strong carcinogens---if they were they wouldn't be on the market. No 100% guarantees, new ones are always being found, but varnishes and solvents are pretty heavily tested for this sort of thing.

Not to say you shouldn't be concerned: the target organs for most of these compounds are the usual suspects: eyes, respiratory system, liver and kidneys. The lungs and the liver are probably the most serious concerns.

But you should be concerned with safety even with someing as benign as shellac (which is diluted with alcohol, by the way). Wear nitrile gloves (not latex), work in a well-ventillated area, and don't stick around while the objects dry. If you go with a varnish, use a volitile-organic half-mask, like one of these.
posted by bonehead at 9:45 AM on January 11, 2006

You can use tea!
posted by agregoli at 11:04 AM on January 11, 2006

Shellac's other uses:

Pharmaceutical - shellac is used to coat enteric pills so that they do not dissolve in the stomach, but in the lower intestine, which alleviates upset stomachs. Its also used as a coating on pills to "time release" medication.

Confectionery - shellac is used to provide protective candy coatings or glazes on candies like Reese's Pieces, because of its unique ability to provide a high gloss in relatively thin coatings (like a French Polish). It was used at one time on M&M's. It is approved by the FDA as a food safe coating when dissolved in pure ethanol (not denatured).

Hats - shellac is used to stiffen felt used to make hats. It allows the makers to shape the felt into brims, bowl shapes, etc.

Food Coatings - because of its FDA approval, shellac is used to coat apples and other fruits to make them shinier.

Electrical – shellac mixed with marble dust is used by lamp manufacturers to glue the metal base to glass incandescent bulbs.

The link gives some other general info on shellac.
posted by caddis at 11:05 AM on January 11, 2006

That's fascinating caddis!

Soy sauce makes a good dark stain - I use it for touch-ups but I guess you could wipe on a coat.
posted by nicwolff at 11:36 AM on January 11, 2006

tung oil
posted by TheLibrarian at 11:56 AM on January 11, 2006

Most tung oil preparations are really just a wiping varnish.
posted by caddis at 12:12 PM on January 11, 2006

I've used roofing tar as a dye before, if you like really dark. If you like the grain, a stain will obscure it (it's like a wash of paint, essentially) while a dye will preserve it (much smaller particles). Or you could leave it natural. "Matte" finishes also can obscure the grain--they have stuff in there to disperse light.

Shellac's the safest. Mineral oil is also used as a safe finish for baby toys and the like if you prefer that kind of a finish.
posted by RikiTikiTavi at 12:42 PM on January 11, 2006

Shellac is also in cosmetics, which the female human uses to attract and hold the non-stick capable male long enough to mate.
posted by weapons-grade pandemonium at 12:47 PM on January 11, 2006

if/when you head to your local hardware store for shellac, check the manufacture date on the can. don't buy anything made over a year ago - it won't cure correctly. you might have better luck at a more specialized woodworking store - they'll have more product turnover.
posted by killy willy at 2:13 PM on January 11, 2006

Shellac is wonderful stuff, but as bonehead said above, it has alcohol in it, so you still need to work in a ventilated area. I got a case of pneumonia from working with shellac a few years ago (I have asthma, which didn't help). It's less toxic than most more modern finishes (it dries more quickly, too), but that doesn't mean you shouldn't be careful.

Still, I would use it again in a heartbeat. killy willy's advice is good, too -- buy it from a specialty store rather than a big box place (we went to Lowe's and they didn't even know what Shellac was!).
posted by litlnemo at 3:15 PM on January 11, 2006

Regarding shellac, there is either white shellac or orange shellac, so use the white if you don't want a spec of colour. Also mix the shellac with a bit of methyl hydrate so that it flows easily. As the others said, you still must wear gloves and mask but it evaporates super quickly.
posted by gina at 7:58 PM on January 11, 2006

Any alcohol will work as a solvent for shellac. Pure grain alcohol is best but expensive because of taxes unless you can get it at lab prices or you know someone with a still. So you want to pick something with the least harmful and low levels of adulterants. Look for less than 5%. And stay away from alcohols that themselves are poisonious like wood alcohol.
posted by Mitheral at 10:24 AM on January 12, 2006

Methylated spirits from the hardware store is what I usually use to cut shellac or for clean up. Just don't wear latex (diswashing) gloves. Alcohol goes right through latex. Nitrile (best), neoprene, and vinyl gloves are all ok.
posted by bonehead at 11:23 AM on January 12, 2006

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