How to determine level of rust inside air compressor chamber(s)?

Question

I've had my Makita MAC2400 about 8 years now, used it mostly indoors for remodeling and some in my shed for auto repairs. I've never drained condensed water from the inside until a friend showed me this video about how rust can make them explode. I had about 1-2 oz of rusty water come out when I drained it.

How can I determine the firmness and reliability of my air compressor with regard to the rust inside its air chambers?

Answer 1

You should send it out for a hydro test. They fill it with water to 1.5x service pressure to test it. You could do it yourself... remove all attachments, rig a pressure gauge on there, fill it with water all the way, pump it up with a grease gun. I've never done it at home before but there is ample instruction on the web.