Will kiln dried pine bleed sap?

[Matt Ranum]

I am putting in a wood burning fireplace and would like to use knotty pine for the mantle. The bottom around the fireplace will be stone while above the mantle will be knotty pine bead board. Its going to come from a box store and will have been kiln dried but do I have to worry about the knots bleeding sap from the heat?

The mantle is not going to be a solid slab, but instead a box type using Pine with small knots. Using stain & poly for a finish.

All opinions & advice are welcome.

[Al Wasser]

I have had pine ooze and ooze and another board never cause a problem. If you can pick stuff with only a few small knots you are probably OK. The larger knots seem to ooze more. Heat contributes to the ooze so heat from your fire place could aggravate the situation. My experience is mostly with Ponderosa Pine, what you get in your area may not be as much of a problem. Personally I would not use pine for your application, but that is me

[John Keeton]

Matt, if there is a pitch pocket there you can guarantee it will bleed. Problem is that those pockets aren't restricted to knots, and can actually be linear areas in the pine.

I'm with Al on the knotty pine for a mantle, both for this and other reasons. But, if its the look you want go for it. You just need to accept the possibility of that happening.

One other issue may be the instability of knotty pine. It is notorious for twisting, etc. around knots. There seems to be a lot of stress in those areas and the heat may aggravate that.

I have used knotty pine in other applications and experienced pitch and movement/twisting. Others may be able to speak to the mantle/heat issue.

[Tony Joyce]

It has to be dried in a hi-temp kiln to at least 160 deg. to set the pitch. A lot of pine is not dried to this temperature, hence the bleeding. This applies to all pines, white and yellow.

Tony

[Steve Schoene]

You can pretty well bet that the pine from the big box stores won't be pine that has been given the full pitch setting kiln drying. For something that will be as visible as this, I'd recommend finding pine from sources more likely to have it be properly dried. That's more likely to hardwood distributors, not lumber yards, and even less likely at the borg.

Also since the mantle shelf has a fair amount of unsupported area, you want wood that won't be so prone to warp as that you find at big boxes. I've never seen such a large percentage of wood with drying defects as the hardwoods and stain grade pine at the big boxes.

Check www.woodfinder.com if you need to locate such a wood source in your area.

[Matt Ranum]

Thanks for the input guys, its much appreciated. There is a lumber yard/ millwork company near me that does there own drying. I think I will check them out this week.

I have worked with pine before with mixed results with the pitch, and its always been the lateral pitch pocket that has given me fits. I figured that I would pick over the wood fairly well and only select those boards with very small knots and no pockets. I am designing the install so if need be I will be able to remove it if necessary down the road and change material.