Outer Grid Design
Here is the Outer Grid. It consists of 6 hoops of .062" SST TIG Welding rod. The hoops are brazed at the intersection points. A description of the fabrication and assembly procedure follows.
Hoops
The hoop circumferenced is measured and cut from the .062" SST welding rod. The hoop was formed aroudna 4" sch 40 PVC pipe. It sprung to approximate dimension after forming. Six hoops were fabricated in this way.
Hoop Brazing
The hoops were brazed together with Nicrobraz. Nicrobraz powder was mixed with Sodium Acetate to act as a binder. The mixture was applied with a SST toothpith to the joint. It was then coated with flux (boric acid using rubbing acohol as the binder) and then heated with an acetylene torch until the flux stopped bubbling and the braz flowed.
Hoop Layout
Next the hoops were marked off into 10 equal 36 degree sections to locate the intersections with the other hoops.
Grid Assembly
The Grid was assembled and the intersection points tied together with #36 wire thread to maintanin the grid shape.
Another Grid View
If you look closely you will see that the grid is made up of identical pentagons and isoceles triangles.
Preparing Joints for Brazing
Each joint was brazed in this simpled fixture. The #36 gauge wire was trimmed off prior to applying the Nicrobraz and Boric Acid. The white material in this picture at the joint is the Boric Acid. The Nicrobraz is underneath.
Brazing Joints
Brazing completed.
Inner Grid Parts
The inner grid was constructed of four annular rings. Slots were placed in the rings to allow them to fit together. The rings were cut on a Laser Table from #16 gauge 304 Stainless Steel. Thanks to Tom Beth of Dynacoil for providing the rings.
Inner Grid Assembled
Here is the assembled Inner Grid. A stand-off was used to allow attachment of the HV electrode. Two more pictures of the inner grid follow.
