Organic Fresnel Lens tree stump remover.

[Gary350]

This is my fresnel lens setting on top of a tomato cage. Lens is 20" x 24". As the sun moves across the sky the 5000 degree 1" diameter spot moves across the stump burning a groove in it as it goes. Every day I have to move the lens to one side about 1" and burn another groove. A stump that has been dead a long time burns up quick. If you cut a live tree down you need to let it dry out about 2 months then it will burn good. My lens has 2 pieces broken out of it.





A few weeks later and a few rains later it looks like this. Now I can mow over it and don't have to worry about hitting it with the lawn mower blade. Put a little dirt on it and in another month it will be grown up with grass and look like the rest of the yard.



If you double click the photos they get larger.

You can buy Fresnel Lens. Several people selling them on ebay. Be sure to buy a SPOT lens not Linear lens.

[Kisal]

That's interesting! I looks like a sheet of plastic, but is it? Did you make it yourself? Did you use multiple layers of material? I would have loved to have had one of those to get rid of tree stumps in my yard.

[!potatoes!]

just a sheet of plastic, with, as the last pic kind of shows, concentric angled grooves in it. make it work like a lens without having to be 3d...I'm betting it was purchased. too precision to be otherwise.

[tomc]

I like burning out stumps. Still burning out stumps has its hazards (like house fires). IMO there probably is no safe way to burn out a stump un-attended.

I might read all the fine print on your homeowners insurance before leaveing a stump fire un-watched...