Current options for moderate duty scuba compressor?
- Thread starter PBcatfish
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I got tired of trying to find the perfect machine, so I decided to get one that met the most specs that I had thought of. One of which is not breaking the bank. I decided on the W31 Alkin Vertical, so I could roll the compressor to the front of the shed to run it and then wheel it out of the way. So far I fill once a week and still have to run a generator to power as my power hasn't been run to the shed. I had the set point set to 5000psi and just watch it. I also got the 2 whip version.
Edit:english
jmcgilroy
Contributor
Sensorcon $129. when I bought mine they had a Scuba coupon for 10% off that price.
Thank you for that.
The price certainly seems attractive.
I have two questions about that unit. What's the calibration procedure like? And is there an internal sensor that needs to be replaced every so often, like with an O2 tester?
ScubaWaltz
Registered
Hi every one, I have a Alkin W-31 220 volts compressor with 127 hours. it pull about 14.5 amps. I've had it for ten years with no issue. I use it to fill my 2 cascade bottles,( I have 3 cascade bottles) If I fill directly from compressor to my 80cf tanks takes about 15 minutes from 1,000 psi. Manual drain every 20-30 minutes. I repack the filters my self for a couple bucks. Not loud when running. change oil once a year. It will go over 5,000 psi If needed.
100days-a-year
Contributor
Ballpark 3.5 cfm and 3.5 hp on that Alkin.
ScubaWaltz
Registered
Yep, 3HP.
jmcgilroy
Contributor
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There's the link to their product page...(I guess I should have posted that in the first place). I'm fairly sure that the calibration has a MAX of 2 years but they say 6 months for some technical use (This gets under +/- 10%) and the 10% number is 10% of the PPM reading...so a reading of 5PPM would be 4.5 to 5.5 PPM. Close enough for us, right? Anyway, I'm happy with mine as I have a gas powered compressor and it absolutely registers when the wind is blowing in the wrong direction.
Here's a place that sells various configurations of the W31 from Alkin, and posts a video of the higher capacity W32 running - Alkin W31 Mariner Vertical Compressor
Now might be a prudent time to take a quick look at some math, pertaining to operational expenses. These are just ballpark estimates. Specific examples will need to be calculated with actual data pertaining to specific equipment, using specific filtration media, running on power at a specific cost, and a specified maintenance schedule.
For the 3-4cfm machines, the filter system seems to usually be a water separator, followed by a second canister with a cartridge inside. Cartridges look to last about 20 fills of an AL80 tank on average, but that varies with temperature & humidity. Hot & humid kills them more quickly. Cartridge prices vary, but for these little machine, $50 seems to be a common price point. If you refill the cartridges yourself, the cost looks to be more like half of that, perhaps less. If we look at a $50 cartridge every 20 tanks, that comes out to $2.50 per fill.
Next lets look at power. If you run a 13 amp 220 single phase motor for 20 minutes, that’s 13 x 220 / 3 = about 1Kwh. Depending on where you live & what time of day you run the compressor, that might be anywhere from $0.11 - $0.60 at current prices that I am aware of. If you run a 120vac motor for 30 minutes at 30 amps, that’s 120 x 30 / 2 = not a big difference.
Now lets take a glimpse at maintenance. If you figure in a $600 valve kit every 500 hours, along with a quart or two of oil & a little time, that’s about $700/500 = $1.40 per hour or maybe $0.50-0.75 per fill.
If you buy cartridges, that might be -
$2.50 filtration + $0.25 power + $0.75 maintenance = $3.50 cost of fill.
If you load your own cartridges, you might be able to knock about a buck to a buck & a half off of that.
If you compare that to paying $6/fill, you are saving maybe 50%. If I figure in my cost of gas to drive to & from a shop that is 45 minutes away, in my truck that gets poor gas mileage, the advantage improves.
If you use 4 tanks per week, that’s roughly 200 tanks per year. At a savings of 50% on a $6 fill, that’s about $600/year in savings. At that rate, a $3k machine would take 5 years to pay you back, if you assume that the machine is trash at the end of that time. If the compressor still works, then you are further ahead by the resale value of the compressor.
Again, these are just ball park numbers for consideration. Your mileage may vary.
For the 3-4cfm machines, the filter system seems to usually be a water separator, followed by a second canister with a cartridge inside. Cartridges look to last about 20 fills of an AL80 tank on average, but that varies with temperature & humidity. Hot & humid kills them more quickly. Cartridge prices vary, but for these little machine, $50 seems to be a common price point. If you refill the cartridges yourself, the cost looks to be more like half of that, perhaps less. If we look at a $50 cartridge every 20 tanks, that comes out to $2.50 per fill.
Next lets look at power. If you run a 13 amp 220 single phase motor for 20 minutes, that’s 13 x 220 / 3 = about 1Kwh. Depending on where you live & what time of day you run the compressor, that might be anywhere from $0.11 - $0.60 at current prices that I am aware of. If you run a 120vac motor for 30 minutes at 30 amps, that’s 120 x 30 / 2 = not a big difference.
Now lets take a glimpse at maintenance. If you figure in a $600 valve kit every 500 hours, along with a quart or two of oil & a little time, that’s about $700/500 = $1.40 per hour or maybe $0.50-0.75 per fill.
If you buy cartridges, that might be -
$2.50 filtration + $0.25 power + $0.75 maintenance = $3.50 cost of fill.
If you load your own cartridges, you might be able to knock about a buck to a buck & a half off of that.
If you compare that to paying $6/fill, you are saving maybe 50%. If I figure in my cost of gas to drive to & from a shop that is 45 minutes away, in my truck that gets poor gas mileage, the advantage improves.
If you use 4 tanks per week, that’s roughly 200 tanks per year. At a savings of 50% on a $6 fill, that’s about $600/year in savings. At that rate, a $3k machine would take 5 years to pay you back, if you assume that the machine is trash at the end of that time. If the compressor still works, then you are further ahead by the resale value of the compressor.
Again, these are just ball park numbers for consideration. Your mileage may vary.
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