pine knots

Hi Bob

If you get the knots filled up with the urethane mix, I would give it a good chance of the knots not spitting later on, I have used and got good results with CA glue, if I was able to get the glue in before the knots had split, then very seldom did they split afterwards. Are you turning the bowls real thin ???, I think that you can get some very nice translucent bowls that way when soaked in the oil, anyway good luck with your project.

Have fun and take care Leo Van Der Loo

Thanks foir the optimism...I do turn them thin enough for them to be translucent. They are really pretty after a half dozen soakings, drying, sanding.

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I haven't tried pine, but Western red cedar will become translucent with several applications of BLO, but it really moves a lot if it from kiln dried stock.

Ken Moon Webberville, TX.

Thanks, Ken. What is BLO?

Not Ken, but Boiled Linseed Oil. Curing oils like linseed, soy or tung are used in all your oil finishes. More or less resin is added to it and the solvent toughen the surface finish.

Problem with conifer knots is that they are a source of resin, and though they might seem to be sealed, they will soften or blister the finish off as they warm up or just exude resin out of pure contrariness. That's why a lot of folks seal their pine with shellac, which uses a polar solvent which won't dissolve the resin. Might want to make the first soak a bit thinner to carry away those resins.

I have recently tried something new, I noticed that after several soaking/drying sequences, if I put the vessel in a sunny place, it "sweat" some oil of the surface. While it was still wet, I rubbed the finish back in. Then, as an experiment, I tried microwaving the vessel to heat it, and lots more finish bubbled out. Each time I did that, I soaked up the excess with cloth and rubbed it into the surface again. That not only stopped the bleeding, it caused the vessel to have a very rich finish.

Not sure why...

Couple of suggestions.

1) You're getting the water out from underneath the oil. See my answer about oiling aspen, where the finish won't cure until it's also got dry underneath. Gooey scatters more light than glossy.

2) You're getting a bit of surface hardening of the wood itself because of the microwave. This will close the pores a bit, giving you an effect similar to burnishing with ultra high number sandpaper.