To: "'North American Fruit Explorers'" <nafex@lists.ibiblio.org>
Subject: RE: [NAFEX] soil solarizaton
Date: Wed, 24 Mar 2004 07:18:53 -0800
Del,
A fresnel lens is a flat lens. I bought a 11"x11" one from Edmund
Scientific. It is only 1/16" thick. Here is a link http://scientificsonline.com/product.asp_Q_pn_E_3052833
It concentrates the sunlight hitting the 11" square surface down to a
pinpoint. As I said yesterday, this concentrated spot of sunlight is
hot enough to melt a small chunk of lead. I don't think it would be
practical for controlling weeds in a large area, but I'm thinking of
using it to keep grass and weeds from growing in the cracks of my
driveway.
-Mark Lee, Seattle