Sorry, I have no suggestions except to add that most softwood pine posts used for fencing are pressure treated with preservative. That is something you probably cannot achieve. Considering the amount of work involved, you certainly want to make sure the wood is going to last awhile. In my area home made fenceposts are usually constructed from locust.

I use linseed oil.

I can't remember where I read it, but elderly person said painting lower section of post with mixture of crushed charcoal & linseed oil would make a fencepost that would last longer than you would. Don't know about pine tho'...it's really soft.

Suzi

you can buy a wood preservative...and treat wood yourself... its highly toxic ... the more toxic the treatment the more effective the preservative...if it doesnt burn your skin off, kill rats, mice and small children it wont be as effective... be careful if you do that...(i am quoting my brother the carpenter...)

Dip the end that goes in the ground in kerosene, they will last for ever

burn the end that goes in the ground with a blowtorch or over an open fire. char it pretty good

My dad a farmer/rancher used to make all his fence posts. He kept a small barrel with diesel fuel and used oil from oil changes and whenever he cut an appropriate sized pole (often pine) he'd peel the bark off and stick them in the barrel giving them at least a few weeks to soak.

Does anyone have the name of a toxic preservative that might really do some good? Something really really toxic? I'm just going to treat bottom few feet, let soak all winter. Use for constructing pole building. Have 6x6 doug fir I cut myself.
thanks

I'm trying to find out if you can still get it but pentachlorophenol (penta) mixed with diesel or any cheap light oil. The longer you leave it in the oil the better.

I've seen several references to used motor oil. You don't have to treat the whole post. 3 feet is sufficient. (Posts rot mostly at the few inches just below ground level: Lots of air, lots of moisture.)

The soak is a long one: 2 months minimum, followed by month of drying.

You will get better penetration if you can heat the oil -- essentially deep frying the logs. This turns some of the water into steam, then let them cool and the condensing steam pulls the oil into the wood.

This is NOT a safe thing to do. Hot oil is dangerous. Flash fires are dangerous. If I were doing this I would heat the oil in a double boiler using a strong dissolved salt mix to raise the boiling point. This will take a lot longer, but I'm a lot more confident I could turn my back on it and not worry about catastrophe.

If you have access to an old vacuum sewer truck, you have potentially a better way: Load the logs into the tank. Fill with oil. Now pull a hard vacuum on the tank, and hold for an hour. Let the air back in. Repeat several times. Pump the oil back into the storage tank.

One of the measures of preservative is pounds per cubic foot. You can do the same. Mark a few logs. Mark the oil level before you put them in the soaking barrel. Mark the max level it gets to. Now after month see how much the level has gone down. Check weekly.

Do all this in shelter to you don't end up with an inch or so of rain water under your oil.

A simple way to maximize longevity by eliminating soil/concrete contact.