How can I 'burn' an old fence post out?

[Rob Morley]

The problem with adding anything combustible is that it will burn, not the wood which is underneath and starved of oxygen. Add an oxidant and the wood will burn.

[AJH]

Yes subject to moisture content.

One of the pyrotechnic projects I never got around to was to remove the wire wound bar cw ceramic from an old radiant fire and rejig it to fit down a hole drilled in a stump, plan was to attach it to an arc welder and just give it enough juice to carbonise the wood in situ. Might work in this case.

AJH

[AJH]

I know but it doesn't work when wet does it? I have never used sodium chlorate and have none to try, yet I have a logstove burning beside me.

I remember as a kid painting potassium nitrate to make a name or word on paper. Then, but only once dried and invisible on the page, the track would burn, started by a cigarette, without the rest of the paper reaching its ignition temperature.

AJH

[Andy]

Although Sodium Chlorate has a fire depressant added, it will still act as an oxidiser: if you don't believe me, try sprinkling some on your log fire next time you have one going,

Andy.

[Martin Bonner]

encourage the wood

I bet you it doesn't! Manufacturing gunpowder is a good deal more complicated than just mixing charcoal, saltpeter, and sulpher together and stirring with a stick.

See

for example.

[DStocker]

replying to Rob Morley, DStocker wrote: Go back to the idea of using Potasium Nitrate, which can be purchased on line for $20 for 10 pounds. Theres a reason they use it for stump remover. Drill holes in the remaining post as far down as possible. I used a 22inch long, 1/2 inch machine bit from HF. The wood was soft so I probably got a good 15" down before friction kicked in. Mix a 1/2 pound or so of Sodium or Potasium Nitrate with water. It should be thin enough to soak into the wood. Keep the sprinklers off. Then fill the holes with the P. N. powder. Can you wait 6 months? Probably not. So speed up the process. Wait a couple days to dry out. A blower of fan would help. Then, light it up! Soak 4 or 5 charcoals, soaked in mineral spirits, on top of the post and light it up. There is not enough oxygen past 15 inches to support combustion with out the P.N. that absorbed P N will smould for up to two days. I've had stumps where the PN gets absorbed into the roots and it smolders 6 feet following the roots.

[tabbypurr]

... if you want the police to take a keen interest. We don't have harbour fright here.

[Paul]

Angle grinder, on the end of a long pole.

Or one of these maybe.

"Where oxy / fuel torches produce a temperature of 2,450?C to 2,760?C, burning bars produce heat in the range of 3,870?C to 4,150?C."

I like his safety outfit.

Who says you can't have fun at work ?

Paul

[harry]

Fifteen years ago, probably dead by now.

[alan_m]

Use Thermite

[Paul]

If you were lowering that into a hole, you'd probably have trouble getting it started.

Thermite will start off a magnesium ribbon, without additional blow torch work. (I did Thermite as a chem department open house demo one year. I wasn't very good at it. I have no future as an arsonist.)

Paul

[DStocker]

replying to jon.p.weaver, DStocker wrote: I have been successful in removing 6 of my 8 posts down to the cement "bottom" (22"), that were rotted out at the top of the cement but your right, it can be a difficult process. Each post had a different level of rot and difficulty. Even then, the new posts were bigger and required plaining to fit the holes. We live in an area where fence contractors just cut the old posts off and dig new holes for the new posts because of the rock tailings from the gold rush. They leave the old crete in the ground. It seems the moisture trapped in the post, as well as the depth of the post in the create keeps it from burning, smoldering, like a tree stump would do after being prepared for burning. But that can take 6 months or more. The depth seems to deprive the burn of oxygen. Charcoal worked well up to about 8 inches. Then, I used a 5/8 drill bit with a

22" shank available at HF. I drilled many holes down as far as they would go and smashed them together with a 6' x 1" carbon steel pry-bar. Then a cheezy planting auger that has about about a 2.5-3" width that I sharpened in the grinder. I pulled the pieces out with a vacuum. I'm thinking, if I had an acetylene torch, I could turn the oxygen on low enough to just feed the smoldering process? Or just it to burn the post out like a small kiln. Maybe a small fan from a computer on the top of the hole to keep the air circulating? There has to be a better way to do this.

[tabbypurr]

crazy expensive though. You don't need acetylene for wood.

? Or just it to burn the post out like a small kiln. Maybe

[Chris Green]

I often (well several times a year I suppose) have to pull old fence posts out as we have a 9 acre smallholding with electric fencing on wooden posts.

I'm lucky to have (and always have had) a mini-tractor with a hydraulic three-point hitch on the back.

When I first wanted to pull the bottom of a broken post out I rather tongue-in-cheek wondered if I could pull it out with the tractor's three point hitch. Much to my surprise it worked quite easily with just some 120mm screws driven into the post in the ground and a bit of chain round them to pull with the hitch.

I now have three big (as in 300mm long by 10mm thick) coach screws that I use to do this and it has never failed so far. I even lifted a the remains of a big square field gate post (300mm square) using this method.

I think it works well because the posts are rarely rotted down into the ground, it's just an inch or so at ground level where there's both water and air.

[Vir Campestris]

I was digging one of our flowerbeds the other day and came across the flint footings of the old outside toilet. I wouldn't have bothered if I'd realised how deep they were... but I also found a three inch post.

I was able to pull it out by tying rope around the top, the levering it with a 6ft crowbar.

Should have used stronger rope the first time. Thinking about it I probably put half a ton of tension on it - and it broke.

Andy

[Cynic]

Another old post dragged up from the depths of homeowners hub ?

[Ryan]

replying to Martin Bonner, Ryan wrote: I?ve burnt down about a foot. Diesel and oil. Powersawed with a 16? bar. Going to dowel a piece of painted rebar into the bottom of new post and broken one. Might look at a sealer before assembly, maybe devcon or rear diff rtv

[ronp849]

I have just removed 2 fence post stumps and dropped new posts into the clean concrete hole. The first post stump was rotten all the way through and was picked out bit by bit after drilling with a long auger bit. The second was sound wood about 5cm down and no amount of picking and drilling was going to remove it. I eventually barbecued it out. A couple of fire lighters in the hole and then 3 or 4 barbecue briquettes in afterwards. Light the fire lighters and allow the briquettes to take. There is a distinct lack of oxygen inside the hole so the burn is slow. I spices things up a it by pumping a very modest stream of air into the hole from my compressor. (A mains driven tyre inflator) via a length of steel tubing. This turned a slow burn into a nearly white hot blast furnace. It took a few hours to burn but what was left was easily dislodged from the concrete and vacuumed out. Next job is to try it on an old tree stump!! Even if it does not work it will be damned good fun trying it.

[Richie]

"No need to recycle the concrete as you won't be able to find it" Gets me every time!

[Lowena]

😂😂😂 having the same Problem