I've used hardware store linseed oil several times. It takes a bit longer to dry, but it's essentially the same as Tru Oil.
As for protecting wood, none will prevent wood from absorbing moisture slowly to reflect the ambient humdity (-) of the environment where they're stored. (This from the dean of the Forestry school at my local University.) The Forestry school placed maple blocks in houses all over GA, side by side. All were dehydraded to the same level, (8 % if I remember correctly.) One block was finished with poly, the other was not. The blocks were inside a non-heated area. At the end of a year, all blocks were the same moisture content.
So basically, nothing keeps out moisture, although rehydration is far slower than dehydration. And so far as protecting the wood, no finish is absolutely necessary except for looks.
This is a summation of a lengthy experiment, and necessarily brief. Only the conclusions are reflected here, and then, not entirely.
The famous thing about linseed oil is that when it gets a bit thin, you can slap on another coat without stripping the entire stock down to the get-go. It will look great. Can't do that with laquer or varnish.
Last edited by Genelang; 07/26/10 10:39 AM.