I'm building my latest contraption. Its a large metal plenum for directing
the air from an air blast sprayer down onto three rows of strawberries.
Think of an air duct for heating with three registers, only use a forty
horse power fan and very small openings.

I made the whole plenum out of sheets of 1/8" steel, and 1/8" round tubing
of different sizes. Its all tack welded together now. I'm going to finish
welding for strength this afternoon. I'll stitch weld with a three inch or
so gap between every one inch of weld.

I'll have yards and yard of places where the metal meets that I need to
seal. It needs to hold up to vibration and high air pressure. And be
paintable. What would you use?

Karl