Request: Compressor setup for dummies

[scubadada]

I frequently dive in SE Florida and pay about +/- $15 a cylinder for nitrox in an AL80, I would imagine that there is a small profit margin in this. I have no interest in taking tanks to get filled when I am a periodic visitor doing up to 4 dives/day.

If your compressor does not pump nitrox, it is worthless to me.

 

[tmassey]

Last time I figured this out (https://scubaboard.com/community/threads/lot-of-complaining-goin-on.16999/page-5#post-9732812) I was paying $15 per fill. Notice that I have $6000 for the acquisition cost for my compressor. That was $4000 for the compressor itself (a 6CFM Bauer-based compressor with autodrains), plus $2000 in other things that I figured out I needed along the way: extra fill nozzles, a long hose so I don’t have to haul tanks 100 feet each way every time I fill the tank, lots and lots of fittings, O2 and CO monitoring, etc. It doesn’t include things that might be considered optional, like the 12 bank bottles I have sitting there. It also includes the $50 a year I pay in compressor oil, the $150 or so I pay for filters per year, etc. And I simply ignored the electricity use.

Could you do it for less? Maybe. You can’t do it for half, which means you’re gonna be paying that same $10 per fill at a minimum. And that’s after roughly a decade of ownership.

Please, please accept the acquired wisdom from the many people who own their own compressors: you will not save money with it.

@clownfishsydney is the only exception to that wisdom that I’m aware of. And the biggest reason is he has a small — but not too small! – and top-quality compressor, that he uses the heck out of. He does hundreds of dives a year. And that’s what drives the cost-per-fill down.

So, if you’re doing hundreds of dives a year, and you buy a small yet very high-quality compressor, you might be able to save some money. Otherwise… Don’t fool yourself.

Now, the convenience is great. The fact that you know exactly what the air quality is is great. The ability to pump nitrox almost as easy as air (but with additional expense!) is great. There’s lots of great reasons. But cost is not one of them.

 

[SouthernSharktoothDiver]

@tmassey Yeah, at this point barring somebody who can show me an actionable, step by step plan with numbers to show that I could save money, I've given up on the idea of saving any that way. And tbh, I didn't expect there to be savings in it after a guy who was selling a compressor on marketplace flat told me there was no savings to be had that way. I simply don't dive enough to get the use out of it. I could see myself getting a setup for convenience if I ever go with the semi-retired rout my current career path has me considering, but otherwise, yeah, I'm more just here for the educational value at this point.

 

[tmassey]

The best write up from a starting-from-nothing perspective that I know of is probably again @clownfishsydney’s website:

Michael McFadyen's Scuba Diving Web Site

This documented the process by which he purchased his compressor, now a quarter of a century ago! It also documents every last little thing that was done to that compressor during that quarter of a century, including a full accounting of all expenses.

Obviously, the actual costs he paid back then bear no resemblance to what you would pay today. But my guess is that 25 years from now the numbers would work out similarly, though larger, of course. Like I said, what makes it work for him is the fact that he did over 300 dives a year using fills from that compressor. You actually do save costs when you can amortize everything over thousands of dives.

So why couldn’t @Wookie do the same with his thousands of dives per year? Because Wookie needed them filled quickly, so he had to buy a much larger and more expensive compressor, with higher operating costs, and therefore higher costs per fill.

By the way, the other website that’s great for compressor knowledge is Scuba Engineer’s:

Bauer Compressors - Scuba Engineer

Bauer Servicing Information All compressor servicing manuals archived on this page are Copyright of the BAUER COMP Holding AG, Munich, Germany. Click HERE

scubaengineer.com

The problem is, while this site has a tremendous amount of information, it’s not organized in a way that allows you to start from nothing. But once you have a general overview, this contains a wealth of additional detailed information.

 

[TrimixToo]

I agree completely with those who say air fills won't be any cheaper with your own compressor. They might even cost you more.

Even nitrox fills will take a long time to pay you back.

But if you dive OC trimix, you can save enough to pay for a really decent system in a few years. IIRC, my (used) Bauer K14, filter towers, PMV, new separator and 4th stage cooling coil to raise the pressure safely, motor controller, flow restrictors, digital gauges, etc., etc., plus 6 bank tanks and plumbing, a trimix analyzer, *and* a Haskel pump paid me back in 4-5 years. But I was doing ~2 trimix dives a week and fills were (at the time) $300+ per set of doubles, plus deco fills. A weekend could easily cost $800 in gas alone.

The typical rule-of-thirds refill was costing me about $75 a set of doubles and deco gas perhaps another $50 when I mixed them with my own equipment.

All these numbers are from memory, so they're worth what you paid for them.

In today's world, if you are younger than, say, 50 and an active diver, you're better off going to a CCR IMO. Your fill costs will plummet (even for trimix), and you can skip some training (like blender and advanced gas blender) and avoid a bunch of equipment cost. My list above is far from comprehensive and does not cover operating costs (testing, filters, oil changes, repairs...).

 

[InWay2Deep]

@InWay2Deep Yeah, kinda what I figured. As I said in the post, I figured that was the case. I was just curious about the breakdown. Sounds like I'd be better off joining the dive rescue team so I can get my fills for free. A plan that'll have to wait a while though, as I'm currently lacking several certifications and the requisite free time.

I wasn't trying to talk you out of it, just setting realistic expectations. If you are doing this solely to save money, you won't. If you are doing this b/c you want another hobby and can justify the upfront expense for some level of convenience then go for it. Some folks in this thread make it seem overly complicated, it's not. It just compressed air. Little add ons like a PMV can easily be added. I really didn't need one at first b/c I wasn't filling tanks from empty, just topping off my Bailout's and my Booster bottles but I have since added one. That's kind of the nice thing, get something cheap to start with, add what you want to it and then down the road you can drop 10k on a big boy compressor if you really want to.

The little 'toy' compressors as they are being called are good for supporting a few divers a week. Just don't overheat it and change the oil/filter regularly. I even take mine on dive camping trips and run it off a generator from time to time to help out my OC buddies.

 

[Tracy]

A home compressor has a ton of value in convenience. It will not save you any measurable money unless you are diving a lot or breathing gases other than air. Even nitrox will take a long time to recoup.
If you can get a quality fill for $10 and it isn't inconvenient for you to access them, go there. You will never make your own for less.

 

[The Chairman]

Compressors are not rocket science.

They are indeed submarine science.

 

[wdeutsch]

Thanks, all, for the breakdown on operating costs. I've been idly toying with thoughts of finding a cheap used compressor, and this thread has fully killed that dream.

For anyone still thinking of it, may I add one other cost to the balance sheet that may be worth considering?

Don't forget lost opportunity cost: The $5K+ you spend on a compressor and setup could just as well be thrown into a basic index fund and spin off around 7% (inflation adjusted) annualy. That's a fair number of "free" fills in perpituity without having to mess with compressor upkeep.

 

[SouthernSharktoothDiver]

@wdeutsch Hadn't even thought of that.

One thing I had thought of was essentially a co-op. As someone commented above, a small but well built compressor, well maintained, can break even or save money if it sees sufficient use. Thus, this leads to the notion of, well, if I and say, twenty other local divers pooled our resources, we could easily buy an excellent compressor setup, and between the lot of us, get more than our money's worth in savings. Of course, I don't know twenty other divers IRL, much less ones I'd want to co-own a compressor with, but the idea is there. Has anyone on here ever done anything of that sort?