Purpleheart bleeding?

[Steve Engelschall]

I've had this piece of Purpleheart for years, and I've never had Purpleheart "bleed" like this. It's at 5% moisture content. If I sand it, the bleeding comes back within a short time.

Question...Can the bleeding be stopped when finishing? Perhaps by hitting it with shellac first? I don't want to use this piece if the bleeding will just return in weeks, months or years.

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[David Utterback]

You have a real stumper. Since no one else has offered, I will take a shot based on general characteristics of wood. I have no experience with purpleheart. The grain is highly figured so I guess internal tension might cause distortion when machined. It may be what is called 'reaction wood.' How thick is the board?

The bleeding pattern certainly looks like a liquid is emerging from inside the board. Do these areas have any odor? My only idea for a cause is that a viscous liquid like propylene glycol got into the wood somehow. It bleeds to a point of equilibrium between coats and then bleeds some more after the surface is sanded. You could try dewaxed shellac as a sealant but that would change the color of the surface and may just slow down the bleeding. I have other ideas on how to 'extract' the contaminant but it may not be worth the effort and expense.

[Steve Engelschall]

The board is currently 7/8" thick, and no odors. When I bought it roughsawn, it was already bleeding - I didn't think anything of it at the time. I will avoid "oily" boards in the future. In the meantime, I sanded it and sealed it with shellac to see what happens over time.