Tech Gas Cost

[Searcaigh]

@mainedvr

I only use Helium on dives below 50m, and carry stage tanks on most dives but use 50% on dives deeper than 30m, even if I'm not on deco, I switch gas at 21m to 50%.

I belong to a small group and we buy our own O2 and Helium to fill our tanks. One of the group also owns a Haskel pump so we can manage to empty most of the Helium from the J bottles.

However as we don't have a compressor our fills are calculated to add air at the end and this is done courtesy of the LDS who then charge a normal air fill which is USD2.2 per fill.

Nitrox here costs USD5.69 a fill no matter what size bottle and up to 50%

For 80-100% the cost is USD11.38 at the LDS.

For the LDS to fill my twin steel 10s with 18/40 I'm looking at USD100 but I pay less than half that though our group.

On deep dives I prefer my stage deco tanks are full. I use S40s for 100% and S30s for 50% and I'll typically breathe 50 bar between 21-6m, and will use an S30 stage probably for two tech dives. The remainder is breathed usually on non tech dives just to allow for some longer bottom times on certain sites where I plan for some short deco, or as mentioned above during some deeper dives to 30m even though I've not run into deco.

Occasionally I'll bring an additional tank for travel gas depending on the dive, 18/40 or 20/20.

By now you'll understand that at a minimum you really need 4-5 regulators, several stage tanks and possibly more than one twinset.

 

[mainedvr]

@mainedvr

I only use Helium on dives below 50m, and carry stage tanks on most dives but use 50% on dives deeper than 30m, even if I'm not on deco, I switch gas at 21m to 50%.

I belong to a small group and we buy our own O2 and Helium to fill our tanks. One of the group also owns a Haskel pump so we can manage to empty most of the Helium from the J bottles.

However as we don't have a compressor our fills are calculated to add air at the end and this is done courtesy of the LDS who then charge a normal air fill which is USD2.2 per fill.

Nitrox here costs USD5.69 a fill no matter what size bottle and up to 50%

For 80-100% the cost is USD11.38 at the LDS.

For the LDS to fill my twin steel 10s with 18/40 I'm looking at USD100 but I pay less than half that though our group.

On deep dives I prefer my stage deco tanks are full. I use S40s for 100% and S30s for 50% and I'll typically breathe 50 bar between 21-6m, and will use an S30 stage probably for two tech dives. The remainder is breathed usually on non tech dives just to allow for some longer bottom times on certain sites where I plan for some short deco, or as mentioned above during some deeper dives to 30m even though I've not run into deco.

Occasionally I'll bring an additional tank for travel gas depending on the dive, 18/40 or 20/20.

By now you'll understand that at a minimum you really need 4-5 regulators, several stage tanks and possibly more than one twinset.

Yeah, I enough gear to get started at least for training I have a few twin sets and AL 80s and 40, nice to get some ideas on how others deal with the cost and what the variables are. Thanks for the input, That's a good idea getting a group of like minded divers and split the cost, as long as all can get along

 

[tbone1004]

@mainedvr , like was said above it all depends on your local gas cost and availability.
Most of my diving is in cave country. $0.12/cf of EAN32, He is about $0.85/cf, and O2 is about $0.45 *todays prices from Amigos who is usually a smidgen more expensive than some of the other shops*.

Unfortunately you didn't really give any dive specifics so you can't figure out a whole lot, but let's do a "worst case dive".
Backmount 120's, filled with EAN32 is $29
AL80 filled with 50% is 13cf of O2=6, plus the balance of EAN32 is $8, so $14 to fill the AL80 with 50%
AL40 of O2 is $18

So you're in for $60 to fill everything from the start, and you'll use probably $40 of gas if you run those realistically for a "normal" dive.

Now, the 120's filled to 21/35 is $19 of EAN32 and $72 of He, so $90 fill for round numbers. You'll use probably $60 of that for a "normal" dive. Cost goes up from there obviously.

If I was filling off the coast of NC, I only have EAN30 and Air available, and it's $30 to fill the doubles regardless of where they are at. Needless to say I bring enough gas to not have to pay for fills while I'm travelling and getting boosted O2/He is extremely difficult.

So, when does it make sense to fill your own gas? In my circumstances almost never, though I do have compressors and blending equipment. I found an O2 concentrator/generator where I can make my own O2 and compress it to 2400psi for the cost of electricity which is negligible. I have a total of about $400 invested in that setup though I got an extremely good deal on it. $400/.45=900cf of O2 to pay for that. Not a huge amount of O2, but if I only count the 100% fills I make, it will take about 15x AL80 fills and that is less than 1 yr ROI on that guy. No brainer. I also have 3 low pressure bottles for banks.

I have a compressor, though it is currently collecting dust. I need to rebuild one of my rixes for a project, but it's a painfully expensive prospect right now with no reasonable ROI and I need another booster much more. If I sell my Hamworthy then I'll do it, but have to sell that first. Once I rebuild my Rix I'll have about $3000 invested in it. That includes 4x bank bottles, nitrox stick, 2x O2 bottles for blending, electric conversion, blah blah blah. $3000 all in, and the power cost for O2 and the compressor is call it $0.02/cf and that comes out to 30,000cf of EAN32 to break even on there *assuming the O2 concentrator/compressor is "paid for" with just O2 fills", and ignoring any other maintenance costs like filters and what not. That's a LOT of nitrox, about 200 fills on double 120's if you're using about 2/3's of them on a fill. I don't dive enough at home to justify that. If I lived closer than an hour away from a local dive site, and didn't have a rebreather, I would have already fixed it.
Matters made worse by the fact that my local fire department lets me use their compressor, so I get free access to a brand new Bauer, I know the guy who maintains it, and I pump more gas out of that thing than they do. Needless to say, my motivation to get my own compressor going is pretty much 0. That fire department happens to be across the street from where I work, and is also about a 1/4mile detour on my way to Lake Jocassee so the convenience is certainly there. They let me plug my long fill whip up as well so I don't even have to take tanks out of the truck. You can't beat that deal with a stick. I have to PP blend everything which is slightly annoying, but it's worth the hassle considering the price.

If you don't have a local FD that will let you get free air fills, if you have expensive gas from LDS's, if you have LDS's that only PP blend, if most all of your diving is done locally, and you find a good deal on a compressor, then it's definitely worth getting your own. I regularly see Devilbiss and Invacare concentrator/compressor units for under $600. That will get you essentially "free" oxygen up to 2000 or so PSI *their stock pressure setting* that can be used for PP blending and O2 fills.
Now, this does not help you with helium unless you are running lean ish mixes and blending through your compressor. For 21/35 I think it's perfectly fine to blend through the compressor and just bank the 21/35 so you don't have to worry about getting another gas booster

 

[mainedvr]

Sooo your saying I should just buy a rebreather got it.... I will let my wife know right away lol

@mainedvr

If I lived closer than an hour away from a local dive site, and didn't have a rebreather, I would have already fixed it.

 

[tbone1004]

Sooo your saying I should just buy a rebreather got it.... I will let my wife know right away lol

It would certainly solve part of your compressor problem...

 

[Jeremy Williams]

The cost of Helium is really the problem. It can vary a LOT from place to place. But even when it's a "good deal" it's still expensive. When it's a "bad deal" it just looks crazy to me. Some of the diving that I want to do really is really too deep IMO without Helium in the breathing gas. I've been looking at the costs of Trimix decompression diving and I keep coming back to the idea that the Helium is expensive and you're just wasting it.

I think I've basically decided that the cost of a rebreather is going to ROI against the cost of breathing gas. It'll take some time, but it's certainly no worse an ROI than the one discussed above for mixing your own helium and buying a Haskell. A rebreather helps with certain logistical elements (you need much less helium and oxygen and the tanks are easier to carry) but it introduces new complexities (you need absorbent, and O2 sensors, and a few other supplies). I think it looks like an eCCR rig will ROI compared to any significant amount of Trimix on open circuit.

 

[tbone1004]

@Jeremy Williams that it will
Hour long dive at 160ft ish will use ~216cf of gas on open circuit, 75 of which is helium at a cost of $65 in cave country for the helium and $17 for nitrox, plus probably $20 in deco gas with Amigos July 2018 pricing.
On a rebreather, probably use 10cf of 21/35 and maybe $5 of O2, and half a scrubber, so maybe $30 total in consumables with cells factored in. $30 vs $110 is $80 saved on that dive. CCR costs about $8k for a good used unit and training, so 100 dive ROI with that profile, give or take. Faster if you go deeper for longer, slower if you do a lot of shallower dives. Half that with the of the prices you guys have quoted

 

[Marie13]

OP, thanks for this thread. I was wondering the same thing.

 

[tbone1004]

OP, thanks for this thread. I was wondering the same thing.

your gas prices at DRIS are cheap enough that you'd have to be either diving a LOT or would have to be really inconvenienced to go to that shop for it to make sense. The ROI would likely never happen on $ savings alone, it would be time/convenience that would pay for it.

 

[Marie13]

your gas prices at DRIS are cheap enough that you'd have to be either diving a LOT or would have to be really inconvenienced to go to that shop for it to make sense. The ROI would likely never happen on $ savings alone, it would be time/convenience that would pay for it.

There’s a super secret, unadvertised air fills deal for regulars. I only pay $5 for banked 32% nitrox fills (the difference between the regular $7 air fill price and nitrox) as a result. I’ll have to check and see what the other prices are. I’m looking at getting a pair of HP100s before next season.

The super secret air fill deal is so good that I will spend one evening a week after work in stop and go rush hour traffic (can take 2 hours down and 1 hour back) to get fills. I don’t drop my tanks off due to the distance. I’ll wait the hour (if getting nitrox) or whatever and shoot the breeze with store staff.

I’d never get my own compressor. I’m not mechanically inclined and have an itty bitty condo with no garage space (the compressor would probably be frowned upon).

I just meant the cost of tech gas as a whole was what I’d been wondering about.