setting pitch in timbers

[brdmkr]

Are timbers for timber frame construction usually kiln dried?  I know that it is hard to mess up dimensional SYP in a kiln, but what about SYP beams (say 4x10s or 6x12s).  If a kiln is not the way to go here, how can you set the pitch?  Is it possible to set pitch in some sort of steam bath (High heat, but high humidity as well)?

Has anyone tried shelac to seal the pitch in on SYP?  I have used it to seal gun stocks on old military rifles.  The cosmoline would leach from the wood every time the stock would get hot.  I sanded them and then hit them with a coat of shelac.  After the shelac dried, I lightly sanded again and applied an oil coat.  I think this use of shelac is called 'spit coating'.  It makes me wonder if it would not hold back sap from SYP as well as the cosmoline.

[jason.weir]

I thought you set the pitch so it would not leach through paint.

I built my timber frame from green white pine and eastern hemlock.  I coated them with linseed oil and I've not seen any sap in the 5+ years we've been in the house?

-Jason

Wondering why you need to set the pitch on timbers?

[Tom]

I'm talking out of school here, but my understanding is that "setting the pitch" is totally heat oriented.  It's not that the heat keeps the pitch from running, it's that the heat gets rid of the part of the pitch that would run.

Heat volatilizes those chemicals that would "run" at a certain temperature, turning them into a vapor and releasing them to the atmosphere.  Since chemicals in the wood, that would volatilize at that temperature are gone, there is nothing to "run".   Still, those chemicals that volatilize at higher temperatures remain.  That's why "setting the pitch" is temperature oriented.

That being the case, I doubt that the type of temperature, dry or wet, would have any differing affect.

[brdmkr]

I

Wondering why you need to set the pitch on timbers?

Well, I may not need to.  I am just thinking some here.  Does anyone know if commercial log home builders or timber frame companies KD their wood?  I am also wondering how you would KD timbers without sever checking.  Of course, checking may not be that bad of a thing in a timber?

[kelLOGg]

I

Wondering why you need to set the pitch on timbers?

I don't think they do. Check out www.cabincreektimberframes or jbell@cabincreektimberframes.com in Franklin NC. He may not be far from you.

[Don P]

Bibby gave a good response to the same question on another thread. Dispersal of defects and the multiple member increase of 15% strength, reduced checking stress.

Some log home companies KD. Checking is pretty much related to species and how hard they push the wood through the kilns. I've used plenty that wasn't and yes, you do get pitch bleeding. We had one with a pitch pocket right over the mudroom/kitchen door in one kd'ed log home that still bled like crazy, so you don't always set all the pitch even with that precaution.

i've got a pair of EWP doors in the house here that I made from upstairs in the barn dried lumber. It did "glow" a little bit with some droplets especially on the panel raises for a couple of years. I knocked them off with my hand. On logs it has been enough flow out of knots to drip down the wall, especially on west facing exteriors.

Facing a green timber to the sun is far meaner than the most hateful kiln operator 

[cantcutter]

My brother is a timberframer. He buys his timbers green from the mill and sets them green. He doesn't worry about pitch, they do tend to seep some, but it doesn't drip or anything. He works with spruce and fir if that makes any difference.