Practical question liquid nitrogen stump removal

[Warpspeed13]

Ok so I need to get a 3foot stump out of concrete without damaging the concrete. It's at that terrible stage where it's to rotten to pull out and to solid to scoop out. My idea is to drill a hole and pour liquid nitrogen down the hole to make the wood brittle and then smash it with a pry bar. Will it make the wood brittle or will it make the wood stronger like it does with a banana?

 

[berkeman]

Ok so I need to get a 3foot stump out of concrete without damaging the concrete. It's at that terrible stage where it's to rotten to pull out and to solid to scoop out. My idea is to drill a hole and pour liquid nitrogen down the hole to make the wood brittle and then smash it with a pry bar. Will it make the wood brittle or will it make the wood stronger like it does with a banana?

Unless you routinely work with liquid nitrogen, this sounds like a bad way to go.

Instead, I googled Stump Remover Chemical Home Depot, and got hits:

http://www.homedepot.com/p/Spectracide-1-lb-Stump-Remover-HG-66420-4/202097353

Looks like there are standard products that do the kind of disolving that you want. Be sure to follow the directions and stay safe!

 

[Baluncore]

Ice can be made very strong by adding sawdust. A tree stump will not become brittle when very cold.

Spectracide Stump Remover Granules are; Potassium Nitrate 100%.
Directions for use include;
THIS IS NOT AN INSTANT PRODUCT. IT IS AN AID TO NATURAL DECOMPOSITION.
To remove stumps, drill several 1-inch holes up to 12 inches deep into stump. Then into the side of the stump, approximately 3 to 4 inches from the top, drill a 1-inch hole slanting down to connect
with the bottom of the center hole (see illustration above.) Pour approximately 4 oz of Spectracide Stump Remover Granules into each hole. Then fill with hot water to dissolve the granules. Continue to add water to the holes for several days to ensure Spectracide Stump Remover Granules dissolve completely. Allow the decomposition process to take place for four to six weeks before removing the stump.

 

[AlephZero]

The main issue with stump remover chemical products is that they are basically nutrients to encourage bacteria and fungi to do the job naturally. That may take a few weeks for a fairly small stump in a warm climate, or it might take two or three years.

The right tool for the job is a vertical stump grinder, but if the tree was growing through concrete that would be probably be a job for a professional, rather than hiring a grinder and hoping you don't wreck it by attacking the concrete instead of the tree.

If you want to try "100% potassium nitrate", you might be able to get it cheaper from a chemical supplier, rather than as a product sold for stump removal.

 

[Warpspeed13]

Na solved it the best way possible the thing was only about half a foot in diameter so we drilled a hole into it and poured thermite in. Turned it to charcoal and broke it out a piece at a time