My friends and I were in need of an air compressor and were able to round up parts and pieces to make a fairly decent compressor.
We were not sure what kind of tank to use that would be safe and ended up using a propane tank. We did everything we could do to avoid welding on the tank itself and I think we did a pretty good job!
To keep it from vibrating around on the floor, we welded the tank to an old wheel / tire. We also placed the tank upside down and used a harbor freight compressor drain kit to keep the moisture out of the tank.
I have no idea how big the compressor head is, but it fills the propane tank in about 5 mins. We have now used this tank for many projects including numerous painting projects and its proven to be very reliable I am not sure I would change a thing.
One thing I did not mention in the video is the wall switch. I was afraid we might walk away and leave the compressor on. Not that this should be an issue but if a line broke I didn't want the compressor to run all day while nobody was in the shop. To solve this answer, we purchased a wall timer capable of handling the load of the compressor. Its good for 60 mins, then you need to reset it, perfect for the shop.
The harbor freight part number for the auto drain kit is #68244