Yes I will post some pics of my cyclone. I built my own pipe also. I was going to use 6" pvc. The 10' pieces were not a bad price but at $25 per wye and T connections it was going to cost me more than the actual cyclone itself. I'm cheap I guess.
As far as the welds go, I took my 2 main pieces to a local sheet metal fabricator and he crimped the edges for me. It snapped right together! It was VERY time consuming but well worth it!