Dave,
Correct me if I'm wrong, but I think you're asking whether it would be OK to apply the Waterlox Satin Oil over an existing gloss finish, or over another finish that you have on hand and want to use up? More a matter of convenience and economy as opposed to some practical reason for combining finishes? I'd say, as long as your first finish is oil-based and not polyurethane or lacquer it should work fine.
Waterlox is a blend of urethanes and tung oil. Practically all the commercial formulas we use for gunstock finishes are blends of synthetic urethanes and natural linseed or tung oils. On occasion, I've lightly sanded an existing oil finish and top coated with a different oil finish. In particular, I'd wager Tru-oil, ProCustom, Permalyn and Waterlox would bond well with each other. I've mixed and matched a few times with good success. In fact, the only use I'd have for boiled linseed oil would be as a cosmetic top coat after making sure the wood was completely sealed with one of the commercial blends.
To the BB at large;
I may have given the impression that Waterlox is the Holy Grail of finishes, that it will magically give the perfect result without effort. If so, I apologize, because it ain't so. There are no shortcuts to a beautiful oil finish on a gunstock....but there aren't any "secrets" either. The techniques I use are well documented and in the public domain. Years ago, I bought a video from Brownells by Joe Balicki, a well respected pro who loves Permalyn. When I bought a bottle of Pilkingtion's Classic oil finish from Brownells, it came with a neat little instruction booklet. Pete Hiatt has an excellent article right here on this site...
http://www.doublegunshop.com/phiatt3.htm All of these sources and others give details of the very same approach I use. With proper technique any of a half dozen products will give good results, and choosing just one is largely personal preference.
I'd like to hear from anybody who tries Waterlox, especially if they already have experience and a strong preference for one of the other popular brands. I know one pro who is a fan of Permalyn and tried Waterlox sealer on my recommendation. He didn't switch. He couldn't tell me why not, he just saw no good reason to change.
