First, I'm looking for common sizes in aircraft-grade square tube, angle and plate to see if there's one appropriate to my needs or if I'm going to have to weld multiple sections together. I've got a project and I need to find an online reference for 6061 aluminum and the like.
Second, I need to know if anyone here is a gunsmith/machinist here who can help advise me on the welding and recommend steps to take in creating a prototype and possibly arranging for a limited production run.

