There is a shop in my area that specializes in surplus metal sheet,rods,tubing, etc. in all alloys. Their most valued stock is Titanium and Aluminum in all grades. I loiter there a lot and usually exit with some thing light weight under my arms. They have been very helpful to my cause.
My most important assets are welders. Good experience tig welders are hard to find that will make time to runs welds for you with a passion.

There is one guy here in Brooklyn that will machine most anything for me because he is just as crazy. He owns a water jet cutter and milling machine which he uses for his specialty BMX bikes he builds. His next project is to cut and hone door latch strikers for my car.