I am trying to decide on what to use for the finish on a bow I have almost completed. I was wondering if I could take Minwax wipe on polyurathane and thin it slightly with acetone then spray it with a spray gun. I have thinned it this way and wiped it on knife handles and bow risers for deeper penetration into the wood and it seems to work. I usually spray on a coat or two of Minwax spar urathane over the wipe on. We always have high humidity in my area and I want the maximum moisture protection I can get without breaking the piggie bank. I have access to Thunderbird but although it is a great finish it seems to me like it doesn't penetrate into the wood that deeply. Besides that the polyurathane is so easy to touch up if you get a scratch or ding.