Flax/Linseed Oil Source?

[DeeAnna]

Linseed is not a preservative for wood; it's a drying oil (meaning it polymerizes with exposure to oxygen) that creates a thin finish coat on wood. If you put it on in thin coats, the linseed polymerizes to form a thin, hard, lasting coating. If it's glopped on too thick, it can't polymerize fast enough before it becomes sticky and rancid and in really bad cases, even moldy.

Copper or arsenic (now illegal in the US) or creosote are preservatives in the sense that they inhibit fungal growth in wood. Even they have to be forced into the wood under pressure to be really effective long term.

 

[BrewerGeorge]

Update for anybody interested:

Upon reflection, I've decided that it's NOT a good idea to throw a ton of iron filings around my garage with its dozens of electric and electronic things, so I've tabled the project until spring when I can do it outside.