I wouldn't be worried about the bumper full of air. I don't think it's enough pressure to really do any damage.

Somebody at my work suggested PVC pipe as an air resevoir.  I was a little sketch about it but I looked up the specs on PVC pipe and a piece of 6" Schedule 80 PVC pipe has a pressure rating of 280 psi that's almost double what most of us would be using at say 100 to 140 psi..  So there has to be a reason nobody is using PVC pipe.. Is it the fittings that are a concern? I would think PVC would be really easy to work with. Think of all those spud guns we built as kids. Creating an explosion in a piece of 4" PVC enough to shoot a potato for 300 yards has got to be serious pressure...

Just some food for thought here's a link to the PVC chart.

http://www.freedomplastics.com/pdfs/Sell%20Sheet_Schedule40-80%20PVC%20Pipe.pdf

Did some more searching and found this site where a guy found a place that sells used air tanks.

Specialty Truck Parts in San Jose.. Here is the link to his article.

http://www.huv.com/jon/jeep/Air/tank.html

ISomebody at my work suggested PVC pipe as an air resevoir.  

Be careful with PVC under pressure ... it will shatter (like glass) when it let's go (i.e. boom)

PVC also breaks easy when it's cold. but the schedule 80 IS a lot better then sched 40.  
A tip for anyone looking for onboard air storage. Hit a welding shop!!!! Buy or lease a small co2 or nitrogen tank and spend the $80-100 for a decent regulator. That gives you from 2600-4500 psi to start with, you can regulate it down as far as you need for an air locker, plus co2 expands as it's released. IIRC a 2' tall tank hold something like 400 cubic feet of co2 |removethispart|@ 2600 psi. (not sure of the exact #, but it's a LOT more then most people think!!) Also runs air tools all day too!
An added benefit if you get a real good regulator, (few hundred $$) is if there is a fire, you can run the tank wide open. Co2 is GREAT on class b-c fires!! )liquids, gases and electric)
Plus it can cool your "after run beverages" too!

Anyone know any drawback to using nitrogen for this?

I'm starting to agree on the PVC thing. I have seen some threads on other sites with the BOOM warning..

Even though it's rated at high PSI it's still not recommended by the manufacturers to pressurize it.

I'm starting to agree on the PVC thing. I have seen some threads on other sites with the BOOM warning..

Even though it's rated at high PSI it's still not recommended by the manufacturers to pressurize it.

Call Sun Performance and talk to them. That's where I got my tank, and pump. It's nice stuff, remember?

-Eric

i found CO2 used to ruin seal as its so cold and makes them brittle