I am having trouble finding 1/4" galvanized piping. I need 4", 9", 10" and a 36" pieces
At least 150 psi but more is fine. Using on compressor.
Having no idea where you live or whether or not there is a Tractor Supply Store anywhere near you, that's where I would suggest you go look for this pipe. The 4", 9", and 10" are called nipples, while the 36" will have to be cut and threaded on the cut end, or you could make it up of 3 - 12" pieces with couplings in between. If no Tractor Supply Stores near you, look for a Menard's or Home Depot, they should also carry these fittings. Good luck.