My father fabricated a rear bumper for my 1965 Chevy, C-10 out of 4" diameter steel pipe. He welded flat end caps on it and added a metal valve stem for filling with air, an air pressure gauge and a female fitting for attaching a short air hose I kept under the seat with the truck jack.
I used it often to air the tires up on my little John Deere lawn mower I used in my mowing business when I was in high school.
Back to your question regarding pipe bumpers. My father was a welder at the overhaul base for TWA in Kansas City for thirty years. He made many pipe bumpers for various vehicles over the years. Many of them doubled as air tanks. Most steel fabrication shops have the capability to cut, mandrel bend and weld most diameters and thicknesses of steel or stainless steel pipe. You may save some time and money by making a cardboard template of the contoured front bumper for the fab shop.
If you run into a dead end, e-mail me personally and I will put you in touch with my father who is a retired, certified A&E welder and fabricates many items for the aviation, agricultural and automotive enthusiats from aluminum, stainless steel and mild steel.
