I ordered some sample pieces and to my surprise, on the tubes that are 11 gauge (.12) or thicker, the weld seam is almost nonexistent. The inside is smooth and I have no trouble telescoping the tubing on those sample pieces. 11-gauge works perfect for my design.
How common is it for the weld seam to not protrude on the inside of 11-gauge stainless square tube? Does it usually (or always) occur this way? Or is it luck?
If the answer is luck, any thoughts on how to get an online supplier to sell me a few tubes that have no weld seam?