Compressors are not rocket science. Anyone with the slightest mechanical aptitude can run one and do very basic maintenance. Believe it or not if you dive regularly enough you will see return on your investment. A lot of dive shops would like you to think they are some sort of voodoo magic that only they are allowed to possess.
We can talk raw costs easily but what people don't always touch on is the convenience factor. Loading tanks into your truck, driving across town to the dive shop, fighting traffic, getting there and finding out the shop's banks are empty or their compressor is down for service.
There is a lot of value in simply being able to fill tanks on your own time without ever leaving your own home. I can fill tanks while drinking my morning coffee or afternoon beer and I never have to leave my garage. I have full control of the process. I know I am getting good and consistent fills and I regularly check to make sure I'm not dumping water or oil into my clean tanks. It's an incredible time saver and you can be fully in control of the process.
Everyone has already touched on basics.
- Make sure your air intake is somewhere it can pull "clean/fresh" air, not next to running vehicles/gas generators/etc.
- Regular filter changes based on hours/humidity/temperature
- You may want to consider a secondary filter stack depending on the unit you purchase some smaller compressors have barely adequate or undersized filters.
- Regular oil changes (hours/seasonal/etc)
- Compressor maintenance when needed.
- Air Quality Testing (quarterly/bi-annually or whatever you are comfortable with)
- I know this is obvious but it's important to note that the air testing really only gives you a brief picture of the quality of air you're producing. It doesnt guarantee that 3 weeks later you won't have an issue that causes it to fail testing.
I cannot speak on any sort of authority on the Max-Air 35. My recommendation is to go bigger if you can afford it. I own another brand small ~3.6cfm compressor which I have been very happy with but If I had to do it all over again I would buy a 5cfm+ compressor. At some point I will upgrade. My understanding is the Max-Air is not designed for continuous duty.
It gets very painful if you're having to fill 4-5 cylinders ~3 days/week with a smaller compressor but it's still far better than fighting an hour of traffic both ways to get to a dive shop in Friday rush hour traffic.
It's hard to say what I have into my compressor and fill panel setup since I did not keep track of the costs but I would say I have about $8-9k into the compressor/panel/fill station. I recognize this is pretty short money compared to most people's setups. Some people own compressors that cost 2-3x the cost of my setup. This includes stuff like compressor, nitrox stick, larger secondary filter tower/stack that goes into a 5-port manifold that has 3 additional fill whips.
Nitrox fills are in the $16-20/tank range in my area. In the summer I try to dive 3-6 times a week and that doesnt include my wife diving. 20 x 6 = $120. It adds up very quickly. I did a whole spreadsheet a couple years ago tracking costs but of course now I can't find it.
