[julianburke]

Pressure banding was a rather easy finishing step. The outside faceplate was wrapped with a clear plastic tape much like packing tape. The banding material was steel package strapping and we used a Pneumatic Strapping Tool Air Bander Strap Tensioner and I forgot what it was set at but it was very tight. We used a jig to hold the mounting ears in place. The theory is that if the side of the tube cannot expand, and the faceplate is hit, it cannot implode. Striking the faceplate makes the sides expand and it will implode unless the strapping prevents that.

After the tube is let down to air (nitrogen) the pressure band is now removed; not just the fact that it has to be removed before evacuating & cooking but this has to be done so that it fits perfectly into the vertical lathe to weld on some new neck glass stock and to insert the new gun mount and annealing to the button on the gun mount. You cannot make the tube turn true in the lathe with the band still on it.

For some reason if the strap is suddenly cut on a live tube, the sides will expand suddenly and unevenly which will almost guarantee an implosion. I have seen this happen several times by repairmen trying to remove the mounting ears to fit in another application which results in disaster!