Bleeding Pitch Problem

Kiln-dried lumber hasn't been heated enough to set pitch, and the seepage can seriously damage finishes. November 13, 2005

Question
I have had a complaint about pitch bubbles appearing through the finish on a Douglas fir door. I am not a pro finisher so I thought I'd ask if anyone knows the best way of cleaning this up without damaging the finish. The door is finished with Sikkens.

The root of the problem is that all my material is kiln dried, and the pitch should be set, not leaking through the finish. The door is exposed to direct sunlight. Is the pitch ever completely set, and was my wood not dried at a high enough temperature? Is this a common problem, and what do other people do to deal with and solve this?

Forum Responses
(Finishing Forum)
From contributor C:
Kiln dried does not mean the pitch has been set. If you search the knowledge base here, I seem to remember a temp of 180 degrees for 24 hours is required to set the pitch.


From contributor M:
Your first and best solution is to get the manufacture to replace what they sold your client. A large pocket could bleed for years. We have refinished 100 old fir beams that are still dripping.

The problem is that the pitch will cause a breach in your finish which will allow moisture to get under your finish and peel it from the inside out. Then it is very hard to tell the customer it is not your fault. With that said if you remove the finish and hit the area with a heat gun to warm the sap then get into the area with a cardiac needle and try to draw out the warm sap. Once that is done then inject acetone into the pocket and flush out the area repeatedly.

Once you have flushed out all you think you can and let the solvent dry then inject the pocket with a thin mix of epoxy. But first try to get the door company to take back the door and charge them for the finishing of the new door.


From the original questioner:
To contributor M: It is not a case of one large pitch pocket; there are small beads of pitch that came right through the Sikkens finish. Do you think there is any way to remove the pitch without refinishing the whole door, or do you think it will just continue to bleed?

From contributor J:
As far as I know most softwood lumber is KD 19, depending on its uses and where you purchased it, which means your lumber may be at 19% MC when you made the door(s).

This can contribute to the bleeding because of the wood trying to equilibrate, which means the bleeding will not stop until the wood has equilibrated. Also, if the lumber has been dried at 19% then most likely the pitch has not been set.