Re: Making Danish Oil
Michael Dresdner
There's a lot to unpack here. When Rustoleum bought and reformulated Watco Danish oil they bumped the solids to about 45%, which is about what it had been originally. That made it about equal to most varnishes. The previous owner who had bought it from the original Watco had cut it to around 12%. I suspect Waterlox is also about 45% solids. Bear in mind that solids consists of anything that is not solvent, so both resin and oil count. However, the more oil, the softer the finish.
I'm not sure what you mean by needing a longer working time. Varnish, right out of the can, can be applied in sections, wiped, then overlapped without any problems, and that's what I would suggest. It does not dry all that fast anyway. Adding oil slows the drying time, but is there really any reason to coat the entire piece before wiping off? I've done whole rooms with uncut varnish a section at a time with no problems or witness lines. The one suggestion I'd make is to apply it with ScotchBrite instead of a cloth. ScotchBrite stays wet far longer, won't wick off solvent, and does not get slimy. One fairly small piece can be used for hours without deteriorating. Scrub the (uncut) finish onto the surface and move it about so that you waste FAR less material than if you were working with thinned or oil-laden material. Then wipe off any excess evenly. Try it and you'll see what I mean. It's fast, easy, and gets a lot of resin on quickly and smoothly without worrying about drips or dust settling in. Do one coat a day -- scrubbed wet coat, then wiped off -- until you get the build you want. You'll find this builds a lot faster than Danish oil and gives you a more durable finish, whether you choose alkyd varnish or polyurethane. If you are used to Danish oil, you may find that one coat will do it all. And before you ask, no, there is no need to sand between coats for adhesion as long as you don't wait more than a couple days between applications. For the record, this is a method I've used for decades, written articles about, included in my books, and even did at least two videos on.
I suspect the whole point of Danish oil is to create something so thin that you can wipe it on without wiping off, but that needless "advantage" comes at quite a price; they are selling you less resin, a weaker finish, and a lot more solvent, something that simply evaporates away. Mixing it yourself does the same thing, so I'm at a loss to understand why one wouldn't simply scrub on straight varnish and wipe it off rather than dilute one's material with weaker oil, or with expensive solvent that does nothing except disappear.
My suggestion to you is to look at varnish finishing from a new approach rather than try to recreate something that, perhaps unbeknownst to you, was in fact rather wasteful of both time and materials.
On another note, both Jeff and I have published Danish oil and wiping varnish "make it yourself" formulas in various articles. I don't want to speak for Jeff, but I will say writing this doesn't mean we necessarily think it is the best idea; it simply means our editors asked us to teach that "skill" to our readers.
