Nontoxic Finishes?

Adam Keiper · May 01, 2009, 06:53:00 PM

As a bow and arrow making hobbiest, I've used all kinds of finishes; from linseed, tung, and Tru-oils, to shellac and paraffin, to various water and oil based polyurethanes, and from spar varnishes and laquers, to home spun concoctions and Thunderbird Epoxy. I've wiped, brushed, and sprayed it all, from off the shelf cans to HVLP guns.

Hands down, Thunderbird is my favorite finish. But as a basement bowyer lacking a decent spray booth arrangement, the setup and cleanup time required, and its toxicity, I rarely use it anymore. I've wrestled with finding the balance between wanting an exceptional finish and the desire for non- (or at least low-) toxicity and more user friendly finishes, and have been gravitating towards the latter.

With that said, does anyone care to toss out ideas for non-toxic finishes? It's a tall order, but ideally, they would be harder/tougher than paraffin or shellac, have more moisture resistant than plain oils, have a low odor, be flexible, and just maybe (WooHoo) be offered in a spray can. How knows, maybe there's some completely safe, eco-freindly, soy oil based product out there that you don't have to worry will spontaneously combust when you toss saturated rags in the trash can.

Rob DiStefano · May 01, 2009, 07:21:00 PM

i can't imagine any durable, well curing non-toxic wood finish. in fact, there are none.

personally, i'll seal the wood with thin cya (using a special mask and nitrile gloves, quickly squirting and wiping the cya with pieces of paper towel), then it's min-wax wipe on gloss polyU.

i also like that 'massey finish', slow set epoxy thinned with acetone, but that's way over into the mega toxic zone.

JCJ · May 01, 2009, 07:26:00 PM

You are wise to be concerned. I build bamboo fly rods and have gone to using Titebond III for glueing my rods and 50/50 concoction of tung oil and shellac rubbed on, for a finish as this combination provides a good finish with low toxicity.

rainman · May 01, 2009, 08:15:00 PM

1/3 turpentine, 1/3 Bee's wax, and 1/3 Tung oil.

dino · May 01, 2009, 08:48:00 PM

Fuhr Waterborn Urethane

John Scifres · May 01, 2009, 11:07:00 PM

Most of my career has been spent managing chemicals. Toxicity is a difficult thing to wrap your hands around sometimes. In general, as a hobbiest bowyer, if you use a commercial, consumer marketed finish such as polyurethane, the toxicity is pretty low. You just are not exposed to it enough to be of concern.

On the other hand, it is not a bad idea to do what's best when you can. Lacquers and reactive finishes often use the most toxic materials. Toluene, which os often used in lacquer thinner, is nasty stuff. Epoxies aren't great either. Many people are "allergic" or at least become sensitized to epoxy. CA is probably the most truly toxic of the bunch. Acetone isn't bad with proper ventilation but isn't great either. Shellac is fine as long as you don't drink the denatured alcohol (it's just ethyl alcohol, you know, the kind you drink with some additives to "denature" it or make it undrinkable). Oil based poly isn't too bad as long as you have proper ventilation but long term exposure to any petroleum distillate isn't a good idea. Water based poly is pretty benign in its normal use. Linseed oil is OK. Paraffin is OK.

The best of the ones you mention from a functionality, low toxicity is probably shellac. But it's not as effective as a plastic finish. I use spray poly outside. I'm limited to when I can spray by the weather but I'm in no hurry either.

Keep in mind that you said toxicity. Flammability is a whole 'nuther ball of flame, if you will. I'd bet, from a risk management standpoint that you are more likely to burn your house down with a finish than you are to suffer true toxic chemical effects.

Bjorn · May 02, 2009, 06:15:00 PM

Tru Oil works very effectively as a non toxic weather proof finish-and it even comes in a spray can as of recently. I use it on self bows and arrows, and have restored bows using the wipe on version of Tru Oil.

Greg Skinner · May 03, 2009, 04:42:00 PM

I used the Massey finish on the HH blank I just finished and I was impressed with how easy it was to use by just wiping on. It really makes a hard, tough, waterproof finish with no fancy equipment. I know that the acetone fumes are certainly toxic, but the exposure is very brief (probably takes less than a minute to apply a coat) and not nearly as pervasive as it would be if sprayed. I noticed substantially more ill-effects from the CA I used to seal the wood prior to the application of the Massey epoxy. I'll use a mask next time.