Dwight:

I've heard of people using linseed oil on axe handles and stuff, but I've never done it myself, so I can't speak from experience.

If you want a "paint" that will provide both colour and opacity, then I would take a jar half full of boiled linseed oil to any paint store and give them a few dollars to load it up with the colour of your choice on their paint tinting machine. Mix it with a paint mixing stick. (never shake polyurethane because the air bubbles that form in the poly will take forever to rise to the surface of the poly and break. so you won't be able to use the poly for a long time after shaking it) Use a Q-tip dipped in that mixture to see how well your "paint" spreads and hides when applied to a paint mixing stick.

You can ruin a latex paint by adding too much colourant to it, but glycerine (which is the carrier fluid in paint tinting colourants) won't have any affect on an oil based coating other than perhaps making it take longer to dry. It should still dry to a proper film no matter how much colourant you add to the BLO.

I expect that darkening that you experienced with Teak oil is due to the fact that drying oils like linseed oil are the softest coatings you can get so far as "oil based" coatings go, and dirt from your hands gets embedded in the dried oil over time whenever you grip the chair handles to get up from the chair. You should be able to remove that darkness by scrubbing the chair handles with a Magic Eraser to plough the dirt out of the oil's surface and then applying another coat of Teak oil to restore the gloss.

So, if it wuz me, and to avoid that softenss, instead of using a soft coating like linseed oil I'd opt for a wipe-on polyurethane. This is the stuff I use when I'm refinishing a door or spice rack in my building:



...only my can says "Clear Gloss" instead of "Clear Satin" on the front.

Wipe on polyurethanes are very much thinner (less viscous) than normal brushing polyurethanes and so they self-level very much better. (still, I wouldn't shake the stuff) You'll never see any brush strokes in dried wipe on polyurethane, even if you brush it on with a corn broom. It dries to a thinner coat than a regular brush-on polyurethane, so you need to apply more coats to get the same coating thickness as regular brush on polyurethane.

Also, oil based coatings like boiled linseed oil and polyurethane dry through a chemical reaction, and to prevent your brush or wiping rag from drying and hardening up between coats, wrap it in a plastic bag and keep it in your fridge (good) or freezer (better) between coats. It's a good idea to keep the container of wipe on polyurethane you're painting from in the fridge or freezer between coats too. Wipe on polyurethane doesn't get appreciably more viscous when it's cold, so you can just brush it on normally, just like it was warm.

Really cold temperatures won't harm any oil based coating.

And, of course, just like any oil based coating, you can tint a jar of wipe on polyurethane in the paint tinting machine to the colour of your choice. The glycerine added with the colourant won't do any harm to wipe on polyurethane no matter how much colourant you put in (except perhaps make it take longer to dry).

PS: You don't need to know the rest...

The reason they use glycerine as the carrier fluid in paint tinting colourants is because, being an alcohol, it's soluble in both water and mineral spirits. Consequently, your local neighborhood hardware store can tint both latex and oil based paints (which is all of the paint it sells) with the same colourants in the same tinting machine.