Enough air will definitely get in through a pinhole. I have built lots of handrail and you never weld those tight. I leave open ends in unseen spots...
None, All the channel's are 8" x 2 1/2" x 1/2" thick There are 3 of them with the one on the bottom (top, tub is upside down) reversed. The sprocket...
Can you clarify for me exactly how you'd use bracing? I want access underneath from the front, and most likely a shelf or lower tier underneath; are...