Tumbling and O2 cleaning

[scubadiver888]

I'm new, Have my OWC dives March 29th and 30th. I have all my gear including 2 Al80s. I was hoping to convert one of them to be used for nitrox. I had both hydro tested in January. I called my LDS to see what it would take and she said it would need to be tumbled and 02 cleaned. Where on earth do I need to do this?

This seems odd to me. I worked for two shops. One did partial pressure blending but did not do tumbling or cleaning. They did however know where to send your tanks to get them tumbled and cleaned. The other shop was a tech shop and did everything. So if your tank needed a tumble they had the equipment to do that. In both cases they either did it or could direct you to a place which did it.

So any shop which requires your tank to be tumbled and O2 cleaned but cannot tell you how to do this is REALLY weird. Do they rent nitrox tanks? If they do, who tumbles and O2 cleans their tanks when they need it? The only think which I can think is that they send their tanks to a competing shop for much less than they charge for things and they don't want to direct you to that shop for fear you'll not come back to them. Maybe there is another reason but that is what first pops to mind for me.

Additionally, everyone in my area does partial pressure blending and everyone does visual inspections. If the tank needs more than their shop can handle, they have companies they can send the tank to for more. If they are filling from a bank of nitrox (32% and 36% only) then you don't need the equipment O2 clean. Basically, if the oxygen is under 40% then there is no need for 02 clean equipment. If you are doing partial pressure blending then you fill the tank with 100% oxygen and top it off with regular air until the total O2 level is what you want, e.g. 32%. Because you are putting 100% oxygen in the tank, the tank and valve much be O2 clean. Once the air is added, the gas coming out will be less than 40% oxygen so your regulator does not need to be O2 clean.

Also, did you have this shop hydrostatically test these tanks for you? Every time I go to get tanks hydrostatically tested all shops ask me if I want them O2 clean for nitrox. They understand that it will only cost a few more dollars to do it while it is being tested but it will cost a lot more if I want to get them O2 cleaned after they come back from hydrostatic testing. Why didn't this shop (or whoever did the hydrostatic test) not suggest you get them O2 cleaned for nitrox.

Bottom line, find other places which advertise visual inspection and hydrostatic testing. You should be able to find someone who can do everything for you. In might even find they cost less than your current shop.

 

[Sonnylynnvick75]

I called today and talked with Steve the owner, There was a slight miscommunication, Steve said that the tank would need to be 02 cleaned and slightly tumbled for the 02 cleaning process. He said that they would ship off the tank for me to the place where they have theirs done. I checked with him on some stuff and he said they have a current deal going on of an Aluminum80 nitrox tank brand new ready to go for $230 with an $80 refill credit meaning basically a brand new tank for $150. I think that is the route I'm going to take.

---------- Post added March 12th, 2014 at 02:27 PM ----------

This seems odd to me. I worked for two shops. One did partial pressure blending but did not do tumbling or cleaning. They did however know where to send your tanks to get them tumbled and cleaned. The other shop was a tech shop and did everything. So if your tank needed a tumble they had the equipment to do that. In both cases they either did it or could direct you to a place which did it.

So any shop which requires your tank to be tumbled and O2 cleaned but cannot tell you how to do this is REALLY weird. Do they rent nitrox tanks? If they do, who tumbles and O2 cleans their tanks when they need it? The only think which I can think is that they send their tanks to a competing shop for much less than they charge for things and they don't want to direct you to that shop for fear you'll not come back to them. Maybe there is another reason but that is what first pops to mind for me.

Additionally, everyone in my area does partial pressure blending and everyone does visual inspections. If the tank needs more than their shop can handle, they have companies they can send the tank to for more. If they are filling from a bank of nitrox (32% and 36% only) then you don't need the equipment O2 clean. Basically, if the oxygen is under 40% then there is no need for 02 clean equipment. If you are doing partial pressure blending then you fill the tank with 100% oxygen and top it off with regular air until the total O2 level is what you want, e.g. 32%. Because you are putting 100% oxygen in the tank, the tank and valve much be O2 clean. Once the air is added, the gas coming out will be less than 40% oxygen so your regulator does not need to be O2 clean.

Also, did you have this shop hydrostatically test these tanks for you? Every time I go to get tanks hydrostatically tested all shops ask me if I want them O2 clean for nitrox. They understand that it will only cost a few more dollars to do it while it is being tested but it will cost a lot more if I want to get them O2 cleaned after they come back from hydrostatic testing. Why didn't this shop (or whoever did the hydrostatic test) not suggest you get them O2 cleaned for nitrox.

Bottom line, find other places which advertise visual inspection and hydrostatic testing. You should be able to find someone who can do everything for you. In might even find they cost less than your current shop.

The shop does Visual inspection but doesn't do Hydrostatic testing. I had to take my tanks to the local Fire protection place and have them hydrostatic tested. I called and asked if they did O2 cleaning but they had no idea what I was talking about.

 

[Colliam7]

The shop does Visual inspection but doesn't do Hydrostatic testing. I had to take my tanks to the local Fire protection place and have them hydrostatic tested. I called and asked if they did O2 cleaning but they had no idea what I was talking about.

This is, in general, standard practice. Most scuba shops do NOT perform their own hydrostatic testing, but many will perform oxygen cleaning. Most facilities that do hydrostatic testing DO NOT perform oxygen cleaning.

Most scuba shops send cylinders out for hydrostatic testing, then VIP and, if requested, clean them for oxygen service after the hydrostatic inspection is completed.

 

[Sonnylynnvick75]

Right, I talked over conversion pricing versus every other option, I ended up biting the bullet and bought a brand new Nitrox tank AL80. It came ready to use with boot, nitrox label, and 12 free fills.