Leak testing with shop air

[robmaxfli]

Its an empty R12 system with Mineral Oil and UVDye installed - but I don't have access to Nitrogen - so I'd like to be able to pressurize with normal shop air. I know air 's got moisture in it but I have another Accumulator that I can put on (and ruin) in the process of leak testing. I can put the new Accumulator back on after I find the leak ...
are there any other good reasons not to use compressor air in this situation?
Also, can I add R134 and pressurize it with the shop air.

thanks

[Tim]

Use some R134a to place pressure in the system, do not run system. No shop air!

[robmaxfli]

I don't have a sniffer so I was looking to use soap and water. would this method create enough pressure to use S+W?

[Tim]

I don't have a sniffer so I was looking to use soap and water. would this method create enough pressure to use S+W?

Depends on the size of the leak.

[Dougflas]

Do not use soap and water. You will get better results using Big Blue or Snoop.