I am currently building a chess board (using black walnut and hard maple) and I'm interested in using an "oil and varnish" finish. I have seen this used in other projects but do not have an exact "formula" and was wondering if someone could shed some light.
I appreciate any help.
Oil and varnish are mixed together in varying amounts to create differences in the finish they produce. Straight varnish (which includes polyurethane) will cure fast and hard and generally have a glossy appearance. When oil is added, the finish cures slower allowing more working time and the appearance takes on a satin look when cured. It also will be a softer finish than straight varnish or poly would give and not as protective against wear.
There are a few ways I'd go on your chessboard. One is to use a Danish oil which is an oil / varnish blend. Several companies make this, one of which is Watco. Watco gives the appearance of almost not being finished at all (unless you apply five or six coats) but creates a nice feel and natural look while providing some protection. At first I wasn't crazy about it but now I find the results pleasing. They also make a finish to go on over the Danish oil if you want more protection.
The other way to go is put on a wiping varnish. This is more of a straight polyurethane-like finish but is thinner and goes on smoother. You have to build up the finish by adding more coats but it does make for a uniform appearance. They also call this "wiping poly".
I may make someone laugh but try Behlen's Salad Bowl finish. I used this on a cutting board I made several years ago and am impressed with the look and durability. I only put on three coats but it has held up to scratches, bangs, hot water, detergents, etc. It has more of a semigloss appearance and brings out the grain and patterns in the wood, especially in maple.
Regardless of what you pick, try it on a piece of scrap maple and walnut to see what the end result will look like. You don't want to spend the time building a beautiful chessboard only to dislike the finish.
I hope this helps.
Most Varnish brands don't have any Poly in them. Some of them do. Varnish is an old natural finish and the poly is a new chemical developed finish. The clasic oil finishes like Watco don't use the poly based finishes. I have used lots of varnish over the years and don't buy the Poly style. I don't like the look, personal thing.
I can see where my statement that "...varnishes (including polyurethane)" could be misunderstood. I didn't mean to imply that varnish had poly in it, only that poly is considered a varnish albeit not in the traditional sense. I agree with you, I don't like the look of straight poly, either. Too plastic and fake looking.
Similar to Lou's mix, I've recently started using 1/3 tung oil, 1/3 turpentine, and 1/3 varnish (spar varnish is the toughest). The proportions of the mix can be varied: i.e. more varnish for a tougher finish; more turpentine (usually first coat) for more penetration. Also, when u feel like experimenting a bit, boiled linseed oil can be used in place of the tung oil, mineral spirits in place of turpentine, and different types of varnish can be used.
Brush it on or wipe it on. You can just let it sit and cure for 24 hrs before the next coat, or you can let it tack up (usually within 15-30 minutes) and rub it clean and dry with rags and then put on the next coat 24 hours later. Using the rub it dry method pretty much eliminates the worry about dust but be sure to use lint free rags.
Have fun and experiment on test pieces.