Can I fill my own scuba tanks?
Filling a scuba tank yourself is entirely possible as long as you have a scuba-grade air compressor and filters to ensure that the tank has enough pressure, and the air is of high quality.
Is a scuba tank just compressed air?
Recreational scuba tanks are filled with compressed, purified air. This air contains about 20.9% oxygen. Several risks are associated with the use of pure oxygen in diving.
How is air compressed into a scuba tank?
Air is sucked in through an air filter into the first stage where a large piston compresses the air down to around 100-140psi. The air leaving the first stage is hot as heat is generated as a byproduct of the compression. This needs to be cooled before it enters the second stage or it would ruin the pump.