It seems many of the Stovebolters replying to this post have the "What if the sky falls tomorrow" approach. With regards to hitting someone or being hit, most of these old trucks we all chose to drive outweigh most of the vehicles and are built better than most anything they may strike, with the exception of some of the larger SUVs. Secondly, the pipe bumper is better suited to deflect the forces that occur during a collision with another object. Ever heard of "crumple zones"?
The tube bumper that doubled as a air tank was made of 4" diameter pipe with 1/4" wall thickness attached directly to the rear frame channels. I backed into a steel pipe bollard filled with concrete one time and thought I had hit a parked tank. The bumper did not fail, nor did it explode, even though it had 120psi of air in it. I haven't done the calcs, however the volume of air in a 4" diameter pipe that is less than 6' in length would sound like you sitting on a whopy cushion at your 60th birthday. Not enough air volume to create a problem.
For those of you that think that a custom bumper, fabricated from some type of pipe/tubing is the best fit for your custom Stovebolt, then I say go for it. Many old schoolers may not have the forward thinking mentality required to come up with the next trend. Your idea my be the hot new bolt-on for 2005!
