Baking Tanks in the Oven for O2 Cleaning

[Gilldiver]

I have a 4” PVC pipe coupling and a ½” 90 degree metal electrical conduit bend from Home Cheapo as a blow dry stand.

Use hot water from the tap for the final rinse, as hot as you can get it. For the most part this will be between 120 and 140F and way below any Aluminum aging temps that you would need to worry about. Fill the tank completely and let it sit for a few minutes. The outside tank temp will get close to the water temp. Now quickly drain the water and put in the 90 degree bend and place upside down so that the tank drains on the coupling for support. A 30 second shot of compressed air/nitrox/O2 from a SCUBA tank should have it completely dry. I have never needed more then 2 shots.

Use some good gloves as the tank will be painful to touch at anything above 110F
This also works well for steel and I don’t get any flash rust.

 

[JeffG]

LOL...Bake tanks for O2 cleaning. Too funny.

 

[hydro12]

I have a 4” PVC pipe coupling and a ½” 90 degree metal electrical conduit bend from Home Cheapo as a blow dry stand.

I may give that a shot. My current incarnation involves a 24" long 1/2" diameter pvc pipe that I slide into the tank and use to administer warm blow-dried air through while the tank is on its side. It blows. But in the not-so-effective, negative connotation.

 

[Gilldiver]

I have two 80's and a 40 to clean this weekend. I'll take a photo and post it to show how I do it in the kitchen.

 

[ekewaka]

Heat can damage aluminum long before the melting point. Luxfer and DOT say that the cylinders should never be exposed to heat above 130F. You would probably be safe a bit higher than that, but you definitely shouldn't be heating them in an oven.

 

[PhilEllis]

Someone is misreading the specification. It does not say to subject the cylinder to any heat............

The Direct Evaporation method of measuring contaminants requires that solvent (cleaning fluid) be introduced in the cylinder and that the contents be poured out through a previously weighed cotton paper screen. These are most often known as milipore screens. The SCREEN is then heated in a furnace to evaporate all of the solvent (cleaning fluid), leaving only particulate matter remaining. A comparison of the screen AFTER the test is then compared to the weight of the screen BEFORE the test to determine the weight of the "particulate" remaining on the screen. The flaw with this system is that you must make the assumption that everything that does not flash away is hydrocarbon. I don't think that is a good assumption.

There is no economical way to measure or inspect a scuba cyinder for oxygen readiness or cleanliness. We are left to make a conclusion that a particular cylinder is clean as a result of being subjected to some cleaning process, previously validated. This is why it is SO IMPORTANT to follow a clearly tested and defined process before you make the statement that a particular cylinder is "oxygen clean". I have heard many people on various boards say they need to "inspect" the cylinder to determine if it is oxygen clean. I would love to know what they are looking for and with what device they are looking.

Phil Ellis

 

[Rainer]

Someone is misreading the specification. It does not say to subject the cylinder to any heat............

The Direct Evaporation method of measuring contaminants requires that solvent (cleaning fluid) be introduced in the cylinder and that the contents be poured out through a previously weighed cotton paper screen. These are most often known as milipore screens. The SCREEN is then heated in a furnace to evaporate all of the solvent (cleaning fluid), leaving only particulate matter remaining. A comparison of the screen AFTER the test is then compared to the weight of the screen BEFORE the test to determine the weight of the "particulate" remaining on the screen. The flaw with this system is that you must make the assumption that everything that does not flash away is hydrocarbon. I don't think that is a good assumption.

There is no economical way to measure or inspect a scuba cyinder for oxygen readiness or cleanliness. We are left to make a conclusion that a particular cylinder is clean as a result of being subjected to some cleaning process, previously validated. This is why it is SO IMPORTANT to follow a clearly tested and defined process before you make the statement that a particular cylinder is "oxygen clean". I have heard many people on various boards say they need to "inspect" the cylinder to determine if it is oxygen clean. I would love to know what they are looking for and with what device they are looking.

Phil Ellis

And how they aren't making it worse! Last thing I want someone who isn't sure what he's doing is opening up my O2-clean cylinders and poking around.

 

[hydro12]

Someone is misreading the specification. It does not say to subject the cylinder to any heat............

The Direct Evaporation method of measuring contaminants requires that solvent (cleaning fluid) be introduced in the cylinder and that the contents be poured out through a previously weighed cotton paper screen. These are most often known as milipore screens. The SCREEN is then heated in a furnace to evaporate all of the solvent (cleaning fluid), leaving only particulate matter remaining. A comparison of the screen AFTER the test is then compared to the weight of the screen BEFORE the test to determine the weight of the "particulate" remaining on the screen. The flaw with this system is that you must make the assumption that everything that does not flash away is hydrocarbon. I don't think that is a good assumption.

There is no economical way to measure or inspect a scuba cyinder for oxygen readiness or cleanliness. We are left to make a conclusion that a particular cylinder is clean as a result of being subjected to some cleaning process, previously validated. This is why it is SO IMPORTANT to follow a clearly tested and defined process before you make the statement that a particular cylinder is "oxygen clean". I have heard many people on various boards say they need to "inspect" the cylinder to determine if it is oxygen clean. I would love to know what they are looking for and with what device they are looking.

Yes, I did misread the information in the material, which is often the problem of garnering information from text, especially government and legal text!

My mis-interpreted application of the process was, however, to be used in effect of removing remaining water from the cylinder, as opposed to a step in measuring remaining hydrocarbons. I do agree that to follow a prescribed process known to reduce hydrocarbons to a negligible level is that more important because of the lack of such readily available methods to measure the effectiveness of the removal procedure.

I have two 80's and a 40 to clean this weekend. I'll take a photo and post it to show how I do it in the kitchen.

That would be really helpful and I appreciate, in advance, the pictures.

Additionally, I was reading some material that Catalina has posted on their site explaining that any aluminum cylinder exposed to 350 F or greater temps should be condemned. I'm probably just being argumentative, but it seems possible that even a short stent slightly above 100 F might do the trick to evaporate bits of water. Of course, if there are safer ways like using compressed air and blow drying, it's without much merit, but I guess I just like that the possibility that another solution exists.

Thanks everyone for the info.

 

[texdiveguy]

NEVER 'bake' a scuba cylinder regardless of Al. or St.!!!!! :no

 

[hydro12]

NEVER 'bake' a scuba cylinder regardless of Al. or St.!!!!! :no

But they brown my tortillas so evenly...