Made in china "Scuba" air compressor

[TrimixToo]

People routinely come on scubaboard asking if they can use these cheap little compressors for scuba and are told no a dozen different ways. I don't recall anyone coming on here and telling about how they have been successfully doing it for years without consequences. Never

Well, they do say memory is the second thing to go.*

More seriously, what he said. ^^^ Just do it right, or don't do it at all. The stakes are too high.

* I think I used to know what the first was...

 

[ScubaMadness]

So Ive been seeing a lot of these affordable air compressors from china on eBay, claiming in the title that it can fill a scuba bottle, but Im pretty sure this won't fill a bottle, at least not to 3000 psi. I can also imagine even if it can be filled all the way, It won't be safe to breath. I can never find any reviews about them either. Has anyone used them before for scuba? I could be wrong about all this as well lol

Heres an example of one

DAVV High Pressure Air Compressor Paintball PCP Airgun Rifle Scuba Tank Filling, | eBay

I have one at home for filling tanks for scuba. I also have a fairly good filtration system attached after the unit to filter anything coming out of it. One thing that annoys me is the beelder for moisture emits an oily residue with the water. That is not entirely unusual since my Alkin scuba compressor ( which is down for repairs right now...the reason I have the DAVV compressor to begin with) does a similar thing but not nearly as oily. I trust my filtration stack as I have been breathing off of it for more than 6 years. This DAVV scuba compressor seems to be holding me over well while I work on my Alkin unit. All in all for 2300 it's not a bad compressor but I would advise adding a really good filter after the unit to be safe It could just be my paranoid thinking or caution with new equipment but those are my thoughts.

 

[TrimixToo]

I have one at home for filling tanks for scuba. I also have a fairly good filtration system attached after the unit to filter anything coming out of it. One thing that annoys me is the beelder for moisture emits an oily residue with the water. That is not entirely unusual since my Alkin scuba compressor ( which is down for repairs right now...the reason I have the DAVV compressor to begin with) does a similar thing but not nearly as oily. I trust my filtration stack as I have been breathing off of it for more than 6 years. This DAVV scuba compressor seems to be holding me over well while I work on my Alkin unit. All in all for 2300 it's not a bad compressor but I would advise adding a really good filter after the unit to be safe It could just be my paranoid thinking or caution with new equipment but those are my thoughts.

My concern would be oil flashing over inside the compressor if it is not specifically designed to make breathing air. I'd worry that the filtration stacks might not eliminate the poisonous byproducts that can be created that way, or could saturate and allow them through. Like everything else you breathe, their effect increases with their partial pressures. If the thing runs cool enough, inside the compressor itself where you cannot measure it directly, and you are using a compressor oil made for breathing air compressors, *maybe* it's fine. I have no clue how to turn "maybe it's OK" into "it's all good."

Have you ever had the air tested for that compressor? The results would be academically interesting. However, even if it were performed under worst-case conditions (hottest ambient temperature, highest pressure, longest continuous run time, oldest filters) I'm not sure I'd declare victory if the results were good. "Just because you're paranoid doesn't mean your compressor isn't out to kill you."

That all said, life is risk (shrug). Pick the ones you want to take.

 

[ScubaMadness]

My concern would be oil flashing over inside the compressor if it is not specifically designed to make breathing air. I'd worry that the filtration stacks might not eliminate the poisonous byproducts that can be created that way, or could saturate and allow them through. Like everything else you breathe, their effect increases with their partial pressures. If the thing runs cool enough, inside the compressor itself where you cannot measure it directly, and you are using a compressor oil made for breathing air compressors, *maybe* it's fine. I have no clue how to turn "maybe it's OK" into "it's all good."

Have you ever had the air tested for that compressor? The results would be academically interesting. However, even if it were performed under worst-case conditions (hottest ambient temperature, highest pressure, longest continuous run time, oldest filters) I'm not sure I'd declare victory if the results were good. "Just because you're paranoid doesn't mean your compressor isn't out to kill you."

That all said, life is risk (shrug). Pick the ones you want to take.

The compressor I bought was specifically for scuba I would not be foolish enough to use a standard compressor

 

[JackD342]

If you have shelled out the $$ for a compressor, why not go the last mile and have it tested periodically like the folks that are selling air fills. I don't know how many companies offer the service, but here is the one I am aware of. (and use..)
Compressed Air Testing Services - Compressed Air Testing - Trace Analytics

 

[abnfrog]

I use trace they are great people fast service , great to work with , for the cost twice a year I wouldn't pump with out them ......

 

[SurfLung]

- I have watched the evolution of the airgun compressors since that first "Shoebox" compressor that could theoretically fill an AL80 scuba tank in about a week. And of course the hand pumps. These current ones DO look tempting but if you look them up on YouTube, you will see some remarkable videos that show how rinky dink they can be. For example, they are water cooled because they get hotter than blazes trying to pump 3000 psi in 1-2 stages. They actually have a little water pump connected to a bucket of water to do the cooling. Lately I have seen a couple of them with little radiators attached to accomplish the same thing... And cost about 2/3rds of a real scuba compressor.
- The concept of a duplex cylinder system isn't bad... It's a small piston on top of a larger piston and is used on some very expensive compressors. But the lack of a large 1st stage before the duplex severely cripples the capability of the compressor. For example, I have a RIX SA3 and when the rings went out on the first stage, the whole thing ran far slower and hotter. That large first stage acts like a booster I think. When I restored the 1st stage rings, my RIX went from about 1.5 cfm to 3 cfm and actually ran FAR cooler. Anyway, someone above said the airgun compressors are using the last two stages... Which means they're missing the large 1st stage.
- Search Youtube for the videos and you will find reviews by airgun fans who are filling AL80 tanks. One in particular was very informative... Citing the oil smell left in his tank, how he addressed it with the Chinese cheapy filters... Made his own filter cartridge out of PVC. I think this is the one that shows the filter:

 

[rjack321]

- Search Youtube for the videos and you will find reviews by airgun fans who are filling AL80 tanks. One in particular was very informative... Citing the oil smell left in his tank, how he addressed it with the Chinese cheapy filters... Made his own filter cartridge out of PVC. I think this is the one that shows the filter:

man this guy is an idiot.

No PMV?
Oily residue and odors?
"only leaks a little bit of oil"
doesnt know what a SP cylinder is

He's not actually breathing this air...

 

[rcontrera]

Since one of them exploded, my insurance will not allow me to touch those anymore.

 

[xxrebelxx3]

I'm buying a GX-E-CS4-I. I also bought a filter that uses 3 stage which should make it safe to breathe. However i have no way to test the air to make sure it is infact grade E. If anyone knows how i can test the air quality that would be great. Most of these will take forever to fill a full size tank and they advise not to go over a certain capacity. Should be arriving soon and I'll be trying it on a pony tank to test. I'll let you know if I live. But i can't find any real difference. It doesn't use any oil in it and filtration is filtration so i can't imagine there's any real difference.