Net benefits and true cost of owning a compressor.

[kr2y5]

A thought has crossed my mind a few times of getting a compressor. I haven't investigated it very seriously yet, but I'm sure a lot of folks must have done a thorough analysis of the available options (getting a compressor vs. paying for individual fills vs. getting unlimited fills or a volume discount or some such in a friendly shop that may not necessarily be around the corner, and just investing in a larger fleet of tanks to minimize the overhead). I'm curious what the overall numbers look like, both in terms of financial cost (initial price + all the maintenance) and time cost (repairs, overseeing the fills, etc.). I'm guessing that for most folks, it's more a matter of convenience than it is a matter of real $$$ saving. I'm curious, though, how much convenience one's actually getting after one considers all the factors, and how much one really pays for that convenience, all things considered. I'm sure the numbers are all over the place, and largely depend on everyone's highly specific individual circumstances, I'm just curious to see a bunch of concrete examples if anyone is willing to share. Sorry if all this has been covered already, nothing immediately jumped at me during my brief search attempts. Thanks!

 

[2airishuman]

I don't think there's a financial benefit unless you dive every day.

The advantage is that you perhaps don't need as many tanks, and don't need to spend time and gas hauling them to the dive shop.

 

[cool_hardware52]

You won't save money, you might save time. If you need gases other than air the time saved really increases. I simply could not dive if I had to chase gas. Being able to fill what ever I want whenever I want and know the gas is clean and dry simply cannot be matched with commercial fills.

Tobin

 

[Diving Dubai]

Perhaps I can give you some insight. Our Club used to have it's own compressor, but when we lost our clubhouse location we did a lot of number crunching.

We used to have a Bauer. The annual running costs were $13,500 for Electricity, Oxygen and maintenance (filters and the like)

This served approx 1600 tank fills (we would blend our own Nitrox)

Getting our tanks filled commercially (the same quantity) was $32,000. So while we had a place to house the compressor it was worthwhile. When we needed to look into renting a building to house the compressor then it became cost prohibitive.

If you were blending then you would need an O2 blending whip (approx $800) and maybe a Haskell pump to recover teh O2 when the tank pressure drops ($2000)

However we have a good Local Shop, we can drop in the cylinders at anytime and leave them, picking them up when we want. This vs blending our own when the evening temp is above 100F and humidity is high has a certain appeal. We would fill one evening, let the tanks cool and top off another which ate into your free hours in a week.

 

[Storker]

If you were blending then you would need an O2 blending whip (approx $800) and maybe a Haskell pump to recover teh O2 when the tank pressure drops ($2000)

Not necessarily. There are continuous blending systems which feed the O2 to the compressor intake, with an analyzer cell downstream of the injection point. Our club has one of those. Continuous systems like that can use all the gas in the tank, so the only losses you have are due to adjusting the mix before opening the tank valve. The ones I've seen are limited to 40%, though, so that may be a limitation for some. You'd have to get your deco gas somewhere else.

 

[Diving Dubai]

Not necessarily. There are continuous blending systems which feed the O2 to the compressor intake, with an analyzer cell downstream of the injection point.

I appreciate that there are other blending systems, however these are normally outside the financial means of an individual, and hence I didn't include them

 

[Storker]

there are other blending systems, however these are normally outside the financial means of an individual

Good point, you're quite right.

 

[tbone1004]

I appreciate that there are other blending systems, however these are normally outside the financial means of an individual, and hence I didn't include them

you are completely wrong about that. It is much cheaper than fill whips since you can DIY a system like that for less than $300 with some PVC and whiffle golf balls. Not rocket science, and once you factor in the cost of O2 cleaning all of your tanks, then having a dedicated O2 transfill whip, extra high pressure gauges for transfilling etc etc, I just still can't see why people that dive nitrox regularly would still PP blend unless you need it for deco gasses.
If you want to buy the commercial one, the trimix blender from Amigos is $3200 but injects using solenoids so you actually program the gas in the tank, the mix you want, and it does all of the blending for you through the compressor.

To the OP. You won't save money, depending on the compressor, you can save time. The Rix are my favorite for the volume that an individual dives, and since they are oil-less require a lot less overall maintenance than most compressors, they're small and can be mounted in any direction, gas or electric, relatively portable, and work quite well.

 

[paulw]

The Rix are my favorite for the volume that an individual dives, and since they are oil-less require a lot less overall maintenance than most compressors, they're small and can be mounted in any direction, gas or electric, relatively portable, and work quite well.

Which RIX compressor are you using?

 

[tbone1004]

I own a SA-6, but haven't gotten around to rebuilding it yet. They are what I have extensive experience with prior to moving to SC. There is no real local diving here that warrants me investing money into rebuilding the compressor at this point. It is impractical to bring to Florida due to the cost of nitrox fills down there, and when I dive on the coast or teach in Raleigh I get free fills anyway so it is sitting in the storage unit until the tides turn.