Baking a piece of wood (what?)

[Al Smith]

Probabley depends on the siding Ed .I've got about 12,000 square feet of galvalum standing seam piled up that the finish is warenteed for 40 years .The company is no longer in business though so that's a moot point .

However my shop has been up for some time now and the finish looks as good today as when it was built .The sideing is insulated garage door panals ,galvalum .On that though I've seen that material which was installed in the 70's still retain it's appearance yet today .That's close to 40 years give or take .

 

[Thor's Hammer]

Probably right Al, I just really dislike it as siding. Never minded it for roofing though.

 

[Al Smith]

Well pros and cons .Danged metal sweats or collects moisture which bring up other problems .Ohio is probably as humid as England so I'm sure you know what I'm talking about .

Wood you constantly need to give it a treatment periodically to maintain plus it's not fireproof .Damned if you do and damned if you don't .

 

[woodworkingboy]

During WW2, the Japanese at one point used Pine pitch to fuel their ships. The reason why many many trees were cut. I don't know if the stumps were processed?

Just wondering if the tar being spoken of is simply pitch that remains in a semi-viscousstate after heating, or if it has changed into something else during the process? Pitch takes a long time to dry, if ever completely when still in the tree. I guess the heated goods is some kind of distillate?

 

[Marc-Antoine]

I'm looking at some other informations and I found that:
http://www.maritime.org/conf/conf-kaye-tar.htm

Just wondering if the tar being spoken of is simply pitch that remains in a semi-viscousstate after heating, or if it has changed into something else during the process? Pitch takes a long time to dry, if ever completely when still in the tree. I guess the heated goods is some kind of distillate?

Part of the process is true distillation for the already volatile components like water and turpentine, but the main part which drives to tar is partial destruction / recombination of the heavy phenolic compounds like resin, lignin, tannins ...
Even the cellulose and hemicellulose are destructed, lasting only their carbon skeletons : the charcoal.

 

[woodworkingboy]

A different composition would explain the tar's ability to dry. I have seen Pine pitch start to seep out of more than one hundred year old timbers after they were resawn and the weather turned warm.