Our original source for radiators was Ron Davis Racing Radiators in Arizona. Over time, we found his fin count was too high for street use. The high fin count blocked air flow at low speeds (and high speeds too for that matter) and so the motors would heat up more putting around. At high racing speeds, the high fin count could take advantage of the forced air. For us weekend warrior types, we simply don't track the car very hard so the lower fin count doesn't matter.
For the past few years, we have used a custom radiator shop to make our radiators. We have also used Fluidyne when we couldn't get radiators fast enough from our supplier. Now we are back to using our custom radiator shop. He does extremely nice work.
As for welding a fin...it would take a magician. As for hot glue--hey, whatever works, but I'm not sure I'd trust it too far.
David
