Stripped a cylinder this weekend

[cyklon_300]

Decided to strip an older Al80 that had a ratty-ass yellow paint job this weekend. Removed all the expired VIP and O2-clean stickers, taped over the current ones and hit it with Aircraft Remover brand paint remover and then washed with high- pressure water and dish soap.

The few residual spots of paint got the razor blade and steel wool treatment. A couple of hours later, a nice looking gun metal gray cylinder.

Took it in for a fill today and the inquisition starts...

"I notice your tank has been stripped." Yeah, I did it this weekend, looks good, huh?

"How'd you get the paint off? You didn't use any power tools on it did you?" Nope.

"Sure you didn't use a grinder? I see a lot of swirl marks." Those marks were under the original paint, so they're artifacts of the manufacturing process.

The cylinder is taken to the compressor and is brought back a few minutes later...

"The valve o-ring leaks, the paint solvent must have eroded it." I taped it off, but it's possible...it sat all weekend with 900 psi and didn't bleed down.

"We'll have to send it out for a VIP, eddy test, and have the walls thickness checked...sure you didn't use any power tools?" Well, the VIP expires at the end of the month anyway, so ok...and unless steel wool and elbow grease are considered a tool, no.

I've always been treated fairly at this shop, but this left me wondering if I was being worked...

 

[wrongkey]

I'd wonder the same thing. Just for peace of mind, I might get the VIP done elsewhere, if I were you. It sounds like the shop guy is already all but calling you a liar for denying use of power tools.

 

[MikeFerrara]

If the shop has always treated you fairly before why should you distrust them now? There isn't enough money in a VIP to bother cheating some one over.

I don't think he's calling you a liar. I think he's afraid of blowing up when he fills the tank. There's no telling what folks do in their garage and the huy filling tanks might feel better if they weren't doing it to the tanks he fills.

Shoot the guy that I bought my house from did everything himself. He did it all wrong too. The plumbing was held together with tape. The electric was messed up in the house and the garage. He also messed up the walls and floors. I'm glad I never had to fill a tank he remodeled.

If the valve o-ring was leaking it needs fixed anyway. Most people would go ahead and visual the tank then anyway.

I've got a bunch of tanks. The paint job is messed up on most of them. I only wish I had time to care.

 

[cyklon_300]

I was a liar, but the encounter left me with the impression that he thought I was perhaps not quite bright...asking the same question three times within 3 minutes left me feeling that one of us was having difficulty communicating in English.

I provided a detailed, step-by-step description of the process I used. Granted, there are valid concerns with DIY tank prep...noting the swirl marks gave him legitimate cause to ask about my procedures a second time. I again responded that no power tools were used and no animals harmed in the stripping of the cylinder.

It was the third inquiry that seemed uncalled for and caused me concern that perhaps the stage was being set to unnecessarily condemn the cylinder. The VIP was never an issue, the possibility that I might be being herded into buying a new Al80 was. I get (overly) suspicious when someone treats me like I have the same IQ as a bag of hammers...

FWIW, the cylinder looks vastly better than the previous yellow/gray zebra pattern. I've got the time and the inclination to care about what my gear looks like, and I enjoyed this little project.

The shop has 110 cylinders they want cleaned...maybe I'll become a 'stripper'......ummm, naw....

Mike, your house sounds like a disaster...how did it pass inspection before you bought it? No VIP?

 

[Charlie99]

Did you offer to sit beside the tank while it got filled?

I've heard some real horror stories of what sort of tanks people bring in asking for fills.

Some divers DO have the same IQ as a bag of hammers.

 

[cyklon_300]

treating me like I'm one of the unwashed heathen wasn't engendering any warm fuzzies with a long-time customer.

Is there really a good reason to question if I used a grinder when I've previously stated TWICE that I haven't?...if the shop needs to do CYA, they might want to try and do it with just a little tact.

Maybe, if they'd have put me by the cylinder while it was fillilng and shined a bright light in my face I'd have cracked and admitted I also used some wet/dry sandpaper on one particularly tough spot...

 

[DA Aquamaster]

cyklon_300 once bubbled...
"We'll have to send it out for a VIP, eddy test, and have the walls thickness checked...

Send it out for a VIP? They don't have someone in the shop certified to do them? I'd be at least a little suspicious.

Have the wall thickness checked? I'd like to see how they do that and it really would not tell them anything. If they have any doubts they would have to hydro test the tank to see if the wall strenght were affected. The amount of metal taken off by a power tool in the stripping process would not be the problem, it would be the heat generated by the tool and the potential effect it could have on the heat treatment.

Scratches, marks or dings on the sidewall are not an issue on an AL tank as long as they are less than 1/32" deep. Deeper than that and the tank should fail a VIP due to the potential for the scratch or ding to act as a stress riser in the wall. In general if you have a ding in your tank deeper than the numbers and letters stamped on the shoulder, your tank is scrap metal, otherwise it is probably ok.

I'd seriously doubt what they have to say if they tell you the tank is bad. Given how you stripped it, it should be fine. If they tell you it is bad, I'd ask for proof in the form of a written test report and I'd ask for the tank back. A tank that fails a VIP or hydro must have the DOT number X'd out and/or the tank must be rendered unable to hold pressure (ie. they drill a hole in it) If they condemn your tank and can't provide proof as to why....they owe you for the cost of your tank.

On the other hand, they are probably just being careful, even if perhaps a little ignorant in what they are telling you. There are a lot of stupid people who try to get an unserviceable tank filled and who seem to be unable to grasp the concept of how much damage a tank can do when it ruptures at 3000 psi. You can't really blame a shop for being careful.

 

[Mverick]

Your best bet would have been to strip the tank right before it needed a hydro. So they could send it out to re hydro it after they saw that you had stripped it. Makes them and you happy. You got a stripped tank. They got to hydro it to make sure you didn't ruin the tank.

It is your tank. And you can do whatever you want to it. But that doesn't mean they have to fill it. Cause if it blows up. They are dead, not you. VIS's don't have to be yearly. VIS duration is only a recomendation. Hydro's do have to be done ever 5 years. That's DOT regs.

I don't blame you for being pissed. But I don't blame them either. I don't have any stickers on my tanks. But I VIS my own and fill my own. I have a compressor. I check my tanks around every 6 months...

 

[H2OHead]

cyklon_300 once bubbled...
The few residual spots of paint got the razor blade and steel wool treatment.

It sounds like you had the best intentions, but I hate to be the one to break the bad news to you. You turned a $50 tank into a planter. I say cut it in half and use it for house plants. It’ll surely make an interesting piece. By attacking your stubborn paint spots with a steel wool pad you mechanically embedded fine particles of steel into the aluminum. Sounds like no big deal, huh? Well if it were a highway road sign, it wouldn’t be. Unfortunately, you had to choose a compressed gas cylinder. Everywhere that steel was embedded into the aluminum is going to start to corrode. Don’t cry, mumble, cuss, or stomp. Just understand that since you introduced to dissimilar metals to one another, an interesting little process has begun. The two have very different electrical properties and are having a field day trying to return to their original states. Your tank’s galvanic (or dissimilar metal) corrosion areas are going to quickly suffer from intragranular corrosion now that there is a portal of entry. I know you’re thinking, “okay…so I got some steel on the aluminum..i’ll wash, buff, polish, grind, sand, drill, blast, and pick the steel off”. That might work if you sprinkled steel dust on a slick polished aluminum surface, but you took it a step further. You took a steel wool pad and rubbed and rubbed. Funny how those last stubborn little patches of paint were actually trying like heck to protect the tank from you. All of that good old fashioned elbow grease made sure that you got those steel particles deeper and deeper. Maybe you could buff it up and tell everyone it’s a missile from Iraq or something (people love war memorabilia). Look at the bright side, now you have a spare valve for your save a dive kit.

 

[cyklon_300]

and spoke with a tech rep. I explained precisely how I stripped/polished the Al80 cylinder and what materials were used.

He did not support the supposition that steel wool, used as indicated to lightly polish the exterior surface, would irreparably harm the cylinder or would it be necessary to condemn it as a result of using steel wool.

His concerns were whether the cylinder had been sandblasted, glass beaded, mechanically grinded, or subjected to temperatures >350F.

His recommendation was to wash the cylinder with household detergent, dry, and spray coat with clear acrylic or enamel paint to prevent oxidation.

I'll monitor the cylinder's condition closely for indications of excessive corrosion and should any appear, will have it re-hydroed.