[GMKlenklen]

Ok, sweet.
The reason I didn't specify the application was because net cut is at 12am... it was 12am.

Generally, most connections would be between two or more 10 series tslot excrusions(sp?) at 90* to eachother. Also there would be several bearing block attachments and the ocasional securement of 3/8" plywood or lexan.
no welding.

Thank you all for responding to my very general and poorly constructed question!