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

[jon.p.weaver]

Its that time of year again and I have just lost 4 fence posts...

I know from bitter experience that they are surrounded in a mass of concrete, which goes down about 18-24", so this time I wondered if it was possible to remove the stump (leaving a nice square hole) and simply insert a new post.

Initially it looked promising, as the 'stump' move slightly, but there were so much suction that I couldn't get it out.

So my next attempt was to drill loads of holes into it and then try and break it out.. This kind of worked, but only got me down about 8 inches before this no longer worked (basically because it was so deep that I couldn't get any leverage)

So, as a last resort I tried to burn it!.. I tried using petrol and it just flames, but very little damage appears to be done to the wood.. I then tryed BBQ lighter fluid and that seemed to work better. However, the BBQ fluid has run out and I am back to petrol again.

I am now down to about 15" so I am almost there but its getting frustrating as its taken almost 2 days!

Is there anything I could use to burn/decompose/eat the wood?

This may not help in this case, but certainly the other 3 posts might benifit from your answers.

Any ideas or suggestions about be appreciated

Jon

[meow2222]

Sulphuric or hydrochloric acids would eat it, but theyd also eat the crete.

Can an SDS chisel not mash the wood up?

NT

[Andy]

Pour sodium chlorate (weedkiller ) onto the stump and add a bit of fuel. Sodium Chlorate is an oxidiser and should help the fire along quite a bit. Don't burn your eyebrows off though!

Andy.

[jon.p.weaver]

Do you know what? I have just been thinking to myself why I havn't tried my SDS.. A few months back I bought some HUGE drill bits.. THey would almost certainly do 'some' damage.. Whether it will get the stump out, I don't know.. But its worth a try!

[Rob Morley]

Oxy-acetylene will make short work of burning it out. The best thing to drill it with is a large spade bit - you can get extenders that fit between the drill and the bit.

[Brian]

How about using a metapost "post saver". They have a spike which is profiled to go into one corner of the rotten end of post set in concrete. Hammer post saver in and you end up with socket to take post. You can even use the old post with the rotten bit cut off!! Wickes sell these things as well cost about £5.

[Rob Morley]

That's Metpost in case anyone wants to Google it :-)

[dave stanton]

Sodium Chlorate weed killer is now sold with inhibitors to prevent it being used as a oxidiser, ie for rocket fuel or explosives. I don't know how effective it is though, you may need to get it really hot in order to get to release its oxygen.

Cheers

Dave

[iamwhatiam]

Come on dothe job properly, do it the right way.

It only takes me 1 hr to remove a post and concrete.

post will be approx 2ft in the ground, so how can you burn it out. It will be soaking wet, as the post has rotted. What a mess. Sodium Chlorate weedkiller has a fire depresant in it, so don't try. Oxy is too dangerous, and I have not seen a torch with a 2ft extension nozzle. Do not use Metapost unless its really really necessary. If you do not get them straight to start off with you have posts that lean over. Hit a stone as you drive them in, and they twist. So you have twisted posts.

Even when I drive in 3inch round to 6 inch round agricultural spiked wooden posts into the ground by 2ft deep. Its impossible to get them out by rocking them and pulling. The suction in the ground is tremendous.

2 ways round it.

1 - Literally dig the concrete out, always dig around the concrete, so its clear of the soil and is not supported. If possible leave the post in situ, if not rotted away, as you can lever with it. Chisel the concrete, or split the concrete in half, look for weak spots. As I say it takes me 1 hr to get a post and concrete out.

2 - Why not set the posts half a fence panel away or there abouts. So you are digging and putting in posts in bare ground. Then make up a half panel to fill in the offset. Leave the old concrete in the ground.

When I come round to putting in new posts/panels in its amazing what historical relics of fencing you find.

[Rob Morley]

Danger is my middle name :-)

Metpost repair spurs slide neatly between the post stump and the concrete - it would be quite hard to put them in crooked.

[Chris Bacon]

It won't work. However, if you drill a pilot hole down the middle of the post, and screw a long coach screw in, you might be able pull out the stump with a suitably drilled piece of 4" RSJ or other sturdy lever. Your best bet may be to drill the concrete out at the corners/sides of the posts, and then try pulling the stump out:

OOO holes ### ### stump ###

You need a good "eye", though (the drill but won't like going into the timber, which helps). I removed a row of posts set into a concrete foundation (*why?*) by drilling a channel out of one side:

---------O---------- O ### ###

--------------------

and levering in the vertical slot with a wrecking bar. Probably won't help you, though!

Problems can happen when there are knots, dents, or whatever in the concreted-in stump - or some silly sod has driven nails into the stump before concreting it in! I have come across that. Grr.

[Mike Harrison]

Maybe soak it in a solution of potassium nitrate, let it dry - this ought to encourage the wood itself to burn in the presence of an oxidiser.

Liquid Oxygen would probably work as well...

[bland]

the way to get them straight is simple: clamp the post in the spur before it is put in the ground and keep the post vertical. This makes a mess of the post top so use the old post then throw it away and put the new one in when the spur is done.

bland.

[jon.p.weaver]

I came up with a plan.. Since I am already down about 12", I was going to put a good bit of post in the hole that I had made and then try a "Repair Spur", just to see if it would work.

Sounded like a good idea to me, until I found that 4" Repair Spurs are almost impossible to get.. I even rang Metpost and was told that Travis Perkins and Wyevale are the ONLY people who buy them off them. I already know that TP have none as they checked their centre stock.. So, if I can't get one froM Wyevale, then I am stuffed and its back to the drawing board.

If anyone knows where I can get a 4" version of the Metpost "Repair Spur" I would certainly be interested.

All the best

Jon

[Chris Bacon]

If you're down that far, it'll probably hold better than a metpost anyway.....

[Rob Morley]

You could always use a few bits of angle iron instead :-)

[bumpy]

encourage the wood

Just where do you think you can get potassium nitrate from ??? bombs and all that.

May be fill the hole up with potassium nitrate, a bit of charcoal and maybe a bit of sulphur, mix it up a touch. Put a good heavy cap on it, stand back and set light. That will clear the concrete and make a hole at the same time. No need to recycle the concrete as you will not be able to find it. The neighbours might complain thou ???

[Bill]

In message , bumpy writes

[Mark S.]

You could have just dug the concrete out and replaced it with a new concrete post by now. :-)

Mark S.

[david lang]

Home made napalm? Polystyrene dissovled in petrol to form a paste like goo?

Dave