So I’ve been pounding the old “best finishes” threads, and I’ve realized that relative humidity is more of an issue with a sinew backed bow than just protecting the bow from a rainstorm. Bear grease liberally applied, warmed, and rubbed in multiple times over weeks with a bear grease/beeswax paste topcoat would be my first choice for any self bow, but I’ve been cautioned against using this on a skinned and sinewed bow, as bear grease plus hide glue and sinew could be big trouble with possible rot.
So…I’m after the best water resistance and humidity resistance possible. Tru oil does not actually penetrate deeply from what I’m reading, but it does fill the pores some and then Provide barrier protection with multiple layers application. I’ve used it, and it’s quick, easy, and certainly decent to great at doing its thing.
Shellack is supposedly right up there with paraffin as one of the very best at protecting against how relative humidity fluctuation affects a sinew backed bow…and will stick to anything. I tested some shellack thinned with denatured alcohol over tru oil on a scrap Osage limb yesterday, and this seemed to work just fine.
Then there is the oil based minwax spar urethane that is a barrier protectant, is flexible and tough, and leaves a satin sheen. I’ve seen a lot of people using this over a tru oil finish without issues. I tested this finish on top of the thinned shellack, and that seemed good to go as well.
So here’s what I’m thinking of as a “best-I-can-do to prevent RH from affecting my bows performance” finish…if it works, I think it should become known as the “shock and awe” bow finish.
Tru-oil applied on the back/skins and exposed wood on the sides of the limbs two to three coats to dry.
Then bear grease on the belly and handle sections applied in warm sunshine and low RH conditions in multiple applications to penetrate the wood deeply then wiped off well after final application.
Then 7-10 thin coats of truoil over all bow surfaces as if you were just finishing with tru oil only.
THIS is the only part I’m unsure of. Will the truoil still work it’s way into the bear grease-lined pores and adhere and cure well? IF ANYONE HAS EVER ATTEMPTED THIS…PLEASE POST YOUR RESULTS/THOUGHTS ON THIS THREAD! I’m going to test it in a scrap limb, but It will be hard to tell true results without bending/shooting/stressing the wood.
If that works, then two or three thin layers of alcohol-thinned shellack over the tru-oil.
Sand with 600 grit or use steel wool to scuff shellack and smooth it out.
Then three thinned coats of the minwax spar urethane wiped on and allowed to cure completely between coats with 600 grit sanding between coats and no sanding after last coat.
Once that dries, keep a beeswax/bear grease paste applied liberally then buffed. Apply this paste before and after high humidity hunts and after the season and as needed.
Bear grease in the beeswax is simply to help make it a paste for uniform, easy coverage.
I know it sounds like overkill, but if each element provides humidity protection in its own way but to varying degrees, then it seems like the combination of as many good types of protection as possible that are compatible with each other would be a good idea when chasing the ultimate finish for protection against fluctuations in performance due to changes in relative humidity.
Let me know where you see potential pitfalls or potential for possible/probable failure.
Thanks, Eric
