Hi Workshoppers,
I read an interesting article about workinb pine wood.. It describes a home made oil soak as follows:
1 part urethane or polyurethane
1 part linseed oil
1 part mineral spirit
My query is, where can I source the (poly) urathane as all my searches so far come up with glue or varnishes (which wouldn't make a soak)
Or is there an oil out there with (some of) these components already present?
Thanks
Margo
Varnish is old school poly is new. Varnish has eithe4 linseed or tung oil in it as a base.
Therefore, varnish is a material which consists of resin and solvent. You put it on wood, the solvent evaporates, and the resin is left. Polyurethane (the Minwax at Lowe's) is a type of varnish, although many people seem to be very confused about this. There's three kinds of resins used in varnishes for woodworking: phenolic, alkyd, and polyurethane. Polyurethane has become the most popular these days, mainly because of its greater scratch resistance. Some people complain it looks cloudy, however, although I think this is usually because they use too much.
Varnishes are either water-based, or oil-based, much like paints. Oil-based are older, and probably use either boiled linseed oil or tung oil as their base. They usually impart an amber coloring, because of this oil content (esp. with the linseed oil). Water-based varnishes don't have the amber color, though some say they're not as durable, and other say they've improved with time and the newer ones are.
You can buy non-polyurethane varnishes, but probably not at Lowe's or Home Despot. Some people prefer the phenolic because it's extremely hard and can be polished well. The alkyd preceded the polyurethanes, although typical polyurethanes I believe also have alkyd resin, and are not 100% polyurethane.
Thinning a varnish I think is usually done for the same reason as with paint: to lay thinner coats, in order to avoid drips and runs. "Wiping varnish" is an example of this: the wiping polyurethane you can buy at Lowe's by Minwax is really just regular polyurethane varnish thinned with 50% or so mineral spirits. I've made my own like this, and I greatly prefer it to brushed-on poly because I don't have all the problems with drips and runs I had before. However, it takes many more coats to get the same protection.