Re: Sealing wood with "Poly", Polyurethane (varnish), or varnish (spar) ????
Re: Sealing wood with "Poly", Polyurethane (varnish), or varnish (spar) ????
Ah, Thank you WOG, no apology needed, I think you have it. That may in part explain some of the comments (at least yours re: “Poly”). That does make sense, though I would point out that resin alone (polyester) does not have much strength and may not be able to control the normal checking that happens in the surface of plywood, and light layer of glass should also be included to make sure the checking does not occur.
If we want to drift a bit here , I have read your recipe before for a wood sealer made up of “1 Part Boiled Linseed Oil, 2 parts Mineral Spirits and 1 Part Spar Varnish or Polyurethane”. I am not against it, and I do like a linseed oil finish in a traditional work boat. (The varnish will keep it from having the typical ‘sticky’ surface of the linseed oil.) Just as some thoughts, I like the idea of the recipe if made with ‘spar’ varnish (containing tongue oil), not sure what I think about it with a synthetic polyurethane varnish (but that’s fine). I would like to point out that boiled linseed oil is a vegetable oil and will NOT prevent or inhibit rot. In fact it will almost foster the fungus that causes rot. However, as you point out, it is an effective (traditional) sealer and water repellent, which by the nature of keeping water out will keep rot fungus from growing, and this is where its value comes in. – Can’t say that I ever came across it as being used by wood boat builders (other than builders of ‘reproduction’ traditional boats). The boat builders I knew used Cuprinol. ......Maybe it was a regional thing.
I like your last sentence LOL..... Nah, I do believe it has its place and I have done my share of glass work, I just don’t believe that it is a cure all for everything. Thanks!!
