Timber Framers Guild Forums General General Forum Questions Neutralizing pitch on a Fir step?

Doing some remedial work on a client's home, she asked me if there was any way to keep the sap (pitch) from oozing out of a back porch step? The step is a 3" x 14" piece of Fir which has some obvious signs of wind shake, from early on in the trees life, close to the pith. I've heard of a remedy before, that I can't recall, but have chosen to be selective of placement when using pitchy wood, when I have to, myself ! Does anyone have a remedy? I'm not sure of the finish on the wood, it appears to be a tung oil seeing as how it expels tiny pitch balls on the front and underside of the same step. Any advice would be greatly appreciated!
Thanks from Tom

Only way I know to stop it when it is bad is to plug it with a tight fitting, glued in dutchman.

If you can remove the step and get it out of the heat and sunlight, like inside an air-conditioned shop, you can let the pitch dry out a bit (rub some dirt on it) and then scrape the surface clean. A few coats of marine laquer will hopefully have enough "back pressure" to hold the pitch under the surface.

Good Luck,

Rooster

Rooster- what do you mean by 'back pressure'?

amazing how a piece of wood keeps on moving and exuding stuff and aging beyond it's 'living' life.

I don't know how well this would work on an exterior application, but in the world of furniture making a remedy to oozing pitch on resinous wood is to coat the trouble spot with a good coat or two of shellac. shellac can have just about anything put on over it and can be put over an oil finish if that is indeed what is already there. The shellac will form a hard shell (hence the "shell" in the name) that the pitch can't come through. This works good on pine that is to be painted (pitch will stain the paint and also prevent it from adhering to the wood, causing it to peel) or coated with poly or some such

i was thinking shellac maybe too- orange shellac for the outdoors. (also an excellent finish in itself for wood canvas canoes) this oxidizes off though so some other finish on top would be needed once the knots and pitch pockets are sealed. (this is what makes orange shellac so nice for a canoe bottom- you can recoat as often as you like)

This is the idea I was trying to explain. I my experience, when the pitch gets warm and turns from a crystaline form to a liquid, it also expands causing pressure within the wood, resulting in the "oozing" effect of the pitch. I have dismantled 100+ yr old sawn Pine timber-frame barns that were originally framed green. Once the frames were covered with a roof and siding, the interior beams were sheilded from the sunlight, and many of the knots stopped releasing pitch. So, when I re-expose beams that haven't seen "the light of day" for over 100 yrs to direct sunlight, they start releasing pitch again...almost as if someone had pressed the "pause button".

Rooster