John Brecher / msnbc.com

Thomas Clark cuts the top from one of hundreds of aluminum cans while constructing a solar air heater in his brother's garage in Goshen, Indiana. Standing behind his nephew Alex, 13, is a prototype of the unit, which works by circulating indoor air through black-painted pop cans heated by the sun. Similar models and do-it-yourself plans are widely available online.

When gas prices spiked in 2008, Thomas Clark, a cabinet maker from Goshen, saw an opportunity.

He started a side business making make solar air heaters from scrap and recycled material. His design and materials are basic and cheap: he gets aluminum cans at 55 cents a pound, and 2 x 4 foot plywood sheets scrapped by the RV industry for $2 each. After starting out at a woodworkers' guild, Clark moved the growing operation to his brother's garage.

Clark's project represents tinkering, innovation and entrepreneurship that this area has long boasted of--the traits that helped turn it into a manufacturing center.

As the RV industry tanked with the economy, and Clark's hours were cut by a third in 2009, he had extra time on his hands--and added motivation to supplement his income. Through eBay, Clark has sold about 25 of the 2000 BTU units for $150 each.

"People say 'oh, 2,000 BTU, that's not a whole lot'," said Clark, "but it runs continuously."

It's a modest supplement in terms of heat, and in terms of income, but steady, so long as the sun is shining.