i welded up a rear bumper i used 1/4 inch thick steel rectube i was wondering how much psi it could handle with out deforming or failing and what fitting i should use.

From what I have seen shop compressor air tanks are usually 1/8 inch or less wall so as long as your welds are good your tank should hold as much pressure as you can put to it. I'm building a new bumper this spring myself and have been toying with the idea of using it as a air tank. What type of compressor are you going to use to fill it. I wonder if a arb would be able to handle the job? I've been thinking that I could fill the tank at the shop and then just have the arb to help replenish. But, not sure if the tank would be big enough to inflate four tires or close to it. What are your plans for use of your air tank?

That depends on your welds. It is more difficult than most people think to get an air tight weld. 1/4 steel wont be your limiting factor, your air compressor will be.

i have used my bumper for about 10 years it works good, but will not fill even one tire. it will help reseat a bead and store air while you switch to your next tire. it does take a bit to get it sealed. use a 3/8 or 1/2 steel pipe nipple drill a hole that it will fit into and weld it on. then you can attatch brass fitting to that so you can pressure test the bumper for leaks(soap and water). the arb compressor will work but i don't recommend it for tires 31+. they don't have a 100% duty cycle and will overheat and burn up.i burnt up 2 of them. if you don't already have a compressor i would look for 1 that has a 100% duty cycle and about 3/4hp similar to [URL="http://www.truckn-store.com/product_list.asp?source=&page=1&ID=1999"] hope this helps!!!

also i have been running it up to 150psi with no problems on 2x5x 3/16wall so you will have no problems with the 1/4wall.

I have a used in xcellent condition 3/4 Hp 100% duty cycle 12v air compressor in a box with batt cables air hose and chuck for $300. made by www.extremeoutback.com air compressors. It is the portable unit. Can be hard mounted also. Let me know if any interest

Yeah, no sweat on the air pressure. I made my front bumper and pressurized it to 200PSI (I have a mean-a$$ air compressor at work that runs the bead blaster). Welds will be the weak spot.
Rat