Nth QLD silky oak bleeding sap/resin

[Lyle]

I bought some boards of 1/4 sawn Nth QLD silky oak over 2 years ago. Boards are 8mm thick. Beautiful figure. I've stored these flat and stickered in my shed ever sine I bought them, I'm in Newcastle area.
Made a couple of boxes using the SO as lid inserts.
Finished with shellac as sanding sealer/filler then WOP as clear coats.
BUT the sap/resin keeps bleeding through in spots.
I've tried metho, turps to wipe it off, but over a few weeks it bleeds again.
Help!!!
What can I do???
Thanks
Lyle

[Mobyturns]

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.

[Lyle]

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.

[Mobyturns]

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.