Thread: Nth QLD silky oak bleeding sap/resin

What can you do?

Hmmm, I wish I knew as I have encountered this issue myself at times. It's very similar to how some species of Beefwood react. It almost seems it has an endless supply of sap / resin with some boards. I have encountered it at times in boards, billets, and wood turning blanks as reclaimed and virgin wood from various sources, and all very well seasoned, with almost all that I can remember being from "old growth" trees, not young trees.

In theory the wood should have reached equilibrium, but as wood reacts to changing environmental moisture content I suspect the expansion & contraction "pumps" the vascular structures in the wood - thus oozing the sap.

My only solution is to perhaps try "pitch setting" as the timber industry does with species such as Caribbean (Pitch) Pine - heat to approx 140 - 180 F to set the pitch, which is typical of the high temperature kiln schedules used.

Google "setting the pitch in pine" will give you some information. Setting Pitch - Wood Business explains the theory behind "pitch setting."

ps, I can remember this being an issue for painters in the 1960's & '70's in FNQ when rough sawn weather boards were the preferred cladding for most homes built in that era. Get some hot dry weather then the home owners start complaining.

Thanks for your quick reply. I'll do that research.
I don't think I can heat these boxes to set the sap.
I might have a look at the way I could do the remaining boards though.
I wonder if a thin coat of resin might be enough to seal it in???
Lyle.

Lyle, I've edited my post above so reload the page. As I wrote my reply it jogged my memory. My Dad was a builder in Cairns & I can remember we experienced this issue on a number of homes in that era.

Mostly rough sawn weatherboards had a tapered profile and were not kiln dried and tended to have pretty high moisture content. They shrunk quite a bit after installation and the install method countered this. Profiled (chamfer) weather boards were kiln dried or at least very well air dried.