Pentacryl

[desdawg]

In my reading about cordwood construction I ran across one person who was doing a borate treatment on his logs. The cost of the borate solution was pretty high so he started making his own. His recipe was as follows, everything measured in liters since he is in Canada:
2 liters glycol antifreeze, 1.12 liters 20 mule team borax (from Wallyworld) .8 liters Boric Acid (from a pharmacy), 2 liters water. Heat the liquids to 250 degrees using a candy thermometer to monitor the temperature and slowly mix in the powders. This would be the blue green stuff I was buying at Home Depot for $16/gallon I believe. We were discussing this earlier, maybe in another thread. I don't think this solution does what the Pentacryl does but it is a wood preservative designed to keep moisture out.

[MountainDon]

Glycol antifreeze, or rather polyethylene glycol antifreeze is a more dilute, plus anto corrosive additives, form of PEG1000 which was the original substance used for stabilizing green wood. It has some drawbacks; difficult to impossible to get a finish to stick to it, much slower to be absorbed by the wood as well as slower drying, and it tends to leach out of the wood when it gets wet or heated. But it prevents cracking.

PEG1000 is a concentrated form of polyethylene glycol that is a solid that melts at about 105 F.

Maybe the anti freeze in the mixture helps retard the cracking somewhat while the borax/boric acid helps keep the insects away, or at least keeps them dieing if they feast on the wood. Boric acid has insecticidal, fungicidal, and herbicidal properties. You don't want your kid or your dog licking the wood.

In my searching on this I ran across a website that sold plastic "wood" blanks for making slab clocks. The crazy image of a house wall covering in dozens of identical plastic logs immediately flashed through my mind. Too weird.

[glenn kangiser]

The plastic wood clock could go great on your Trex deck.

[MountainDon]

I negotiated my way out of that.     It'll be PT green stuff like the gazebo. 

[desdawg]

I picked up some treated 2X4's yesterday at the plant where they are treated. I have such a plant in my neighborhood. I asked the guy what ever happened to the old wulmanized lumber with the pecker tracks. He said we can only use that on outdoor products like guard rail posts, fence posts, etc. Anything going indoors has to use the borate treatment. It was his opinion that the offgassing was so minimal no one would even notice. He said every fence post in the country was treated the old way (I don't know the right terminology if you haven't guessed) with horses and cattle gnawing on them for years. Amazingly enough they are not dropping dead all over the pasture.
I am framing knee walls for skirting on a mobile home and am using the treated lumber for both plates and the short studs. Since I am cutting these into 20" pieces I am getting a good look inside. These are being treated in a pressure vat and the penetration isn't complete and uniform. I also have some of the older lumber that I was using up with the incision marks and the difference is apparent immediately. So we take one step forward and three steps back.

[MountainDon]

I could be off base, but I believe the use of the incisor machine is species dependent. Woods like Doug Fir are denser and require that. I saw the machine at the treatment plant here a long time ago... looks like a buch of bicycle sprockets.

The uneven penetration is why the fine print always advises treating the end cuts with brush on preservative.

[MountainDon]

Wood Slab Update:
the Pentacryl treated slab is down another 1.5 ounces; now 5 lb 0.0 oz.
the cobtrol slab dropped 1.5 oz as well; now 3 lb 11 oz.

No cracks at all in the Pentacryl slab, a few more widened in the control slab.