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Post by john7000 on Feb 22, 2014 18:37:26 GMT -8
YankDownUnder posted this (above) in Oct. 14, 2010: "Some were lined with vinyl which needs to be removed, because it hides the rust when a VIP is done."
I have a steel 72 Nemrod that's never been hydro'd after purchase. It has the inside vinyl lining, and the tank has been sitting empty for decades. It looks good on the outside and so I was wondering, is there some way to remove that vinyl lining to return the tank to service?
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Post by john7000 on Feb 23, 2014 16:47:53 GMT -8
Found what reads like a pretty good technique on: www.divematrix.com/showthread.php?9258-Value-of-used-steel-72-sPosted by PeterJ on 02-22-2010, 4th paragraph down: "...If you want to get a resin coating out, you can tumble for ever with normal media or use 3 pounds of stainless steel deck screws and tumble for a few hours. The screws will cut the resin and get it out. Then follow up with a normal media tumble for clean up." However, after looking closely at my tank's lining again with a very bright LED flashlight, dangled inside by a string, that coating looks pristine. I can see no blistering, peeling, etc.
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Post by nikeajax on Feb 23, 2014 17:56:34 GMT -8
Ahhhh, the ol' LED dangled by a string routine Gosh, I'd sure try it, but that's just me: kinda neat having something so utterly-peculiar: I'd never even heard of such a thing, but that don't mean nuttin'... Good luck, Jaybird
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Post by nikeajax on Feb 24, 2014 14:45:40 GMT -8
I just got my Healthways tank back from being hydro'ed, I think it has that coating on the inside too!
Jaybird
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Post by john7000 on Feb 24, 2014 20:51:17 GMT -8
I just got my Healthways tank back from being hydro'ed, I think it has that coating on the inside too! Jaybird Well don't knock it until you see it for yourself. The flashlight I mentioned above is about 1/2 in. diameter and is very bright. I think it works better than that firber optic string my LDS uses. My internal coating looks to be very clean and intact. This LDS told me it had to be removed before I could get a VIP, which I think is bogus (unless there's been some change to a spec recently). This tank has never been hydro'd after purchase by original owner (c.1974) so I know it's got to be okay. And just an FYI re the internal coating: somebody said on another board that he smelled the vinyl in his air. I'd be curious if you could smell anything once you get your filled and start using it.
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Post by john7000 on Feb 24, 2014 22:29:36 GMT -8
Here's a pic of the inside vinyl lining illuminated by my LED flashlight. It looks as clean as it seems in this photo.
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jon
Regular Diver
Posts: 26
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Post by jon on Feb 27, 2014 6:13:19 GMT -8
Regarding the vinyl coating, I just had a visual done on a pair of 72's by a technician who uses vintage gear and was a Seal in the 1970's. Though my tanks were unlined,the subject came up and along with the hidden corrosion issue he said the lining is carcinogenic and should be removed for that reason as well.
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Post by john7000 on Feb 27, 2014 15:09:59 GMT -8
Jon,
You said, "...the lining is carcinogenic..." That doesn't surprise me; I kinda wondered about the potential for something like that.
Now since my last post on the subject, I found another dive shop that looked at the inside and said it was pristine and that the inside lining is a "baked on" finish rather than some kind of apparent vinyl coating. I don't know if that's correct or not, but in any case, he's going to do the hydro next week.
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Post by nikeajax on Feb 27, 2014 16:31:49 GMT -8
John7000, so I've been wondering what the black-stuff in that image is: is that a shadow? Confused in California (sorry, I was trying to make it sound like "Dear Abby")
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Post by nikeajax on Feb 27, 2014 18:12:39 GMT -8
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Post by john7000 on Feb 28, 2014 4:41:46 GMT -8
Nikeajax,
Thanks for that link. I gotta wonder if the early regulators had any PCBs in them; i.e., in the rubber (synthetic) products.
That black thing you see in the image is the flashlight suspended by the string that I mentioned earlier. I put the camera lens right up against the neck to take the picture with the light beaming.
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Post by SeaRat on Feb 28, 2014 13:46:05 GMT -8
Regarding the vinyl coating, I just had a visual done on a pair of 72's by a technician who uses vintage gear and was a Seal in the 1970's. Though my tanks were unlined,the subject came up and along with the hidden corrosion issue he said the lining is carcinogenic and should be removed for that reason as well. I am going to have to say something here. I am a retired industrial hygienist. As such, I have been trained in chemical hazards and exposure risk assessment and management (ERAM). Vinyl chloride is what is called an "A1" carcinogen, which means it is a " Confirmed Human Carcinogen." However, in order to have it be carcinogenic, in must enter the body of the person (diver in this case). Vinyl chloride is not a solid, but is a gas. It may be possible for the plastic liner to off-gas some vinyl chloride, but that would usually happen soon after it was produced. Now, some 30-40 years later, and especially since this apparently is a "baked-on" liner, the potential for off-gasing is very, very small. What about particulates? Well, our regulators have what is called a "sintered filter" which is designed to keep particles out of our breathing air. They are not needed for any other purpose. These filters keep the internals of the regulators from getting messed up with rust, aluminum oxide, etc. Saying that removing the liner is because the liner is "carcinogenic" ignores both the mechanism of exposure for vinyl chloride, and the other materials that the diver could be exposed to. One other metal that we all have in our equipment is chromium. As a metal, Cr III compounds have a time-weighted average (TLV tm*) exposure level for 8 hour per day of 0.5 mg/m 3. Because chromium is hazardous in certain phases (upper respiratory tract and skin irritation) doesn't mean we should strip it off our regulators and valves. Vinyl chloride's TLV is 1 ppm, and the basis for that is lung cancer and liver damage. But that is exposure to the gaseous form. Plastics are a solid form which will be removed from the breathing air by both the valve design (that's what the small tube is for) and the sintered filter in the regulator. John John C. Ratliff, CSP, CIH, MSPH *TLV is a trademark of the American Conference of Governmental Industrial Hygienists; it is a value which is published yearly by ACGIH, and the values I quoted are from the 2013 TLVs and BEIs Booklet by the ACGIH.
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Post by nikeajax on Feb 28, 2014 15:25:56 GMT -8
"Plastics are a solid form which will be removed from the breathing air by both the valve design (that's what the small tube is for) and the sintered filter in the regulator."
Are you saying that the filter on our regulators will filter out the biological-hazard-components before they gets in our lungs--I hope? Sorry, that was a lot for me to digest with my dyslexia!
Jaybird
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Post by SeaRat on Feb 28, 2014 17:29:06 GMT -8
"Plastics are a solid form which will be removed from the breathing air by both the valve design (that's what the small tube is for) and the sintered filter in the regulator."
Are you saying that the filter on our regulators will filter out the biological-hazard-components before they gets in our lungs--I hope? Sorry, that was a lot for me to digest with my dyslexia! Jaybird Jaybird, To me as an industrial hygienist, we divide hazards into several categories: physical hazards, chemical hazards, ergonomic hazards and biological hazards. Under our description, biological hazards would be things like bacterium, viruses, poisons from fish and jellyfish, etc. So when you say "biological-hazard-components" we think in these terms. But I don't think this is your meaning. I think you are talking about hazardous chemicals or particles that can have a biological effect. The sintered filter cannot remove gases, and probably won't remove liquids either. But so far is hazardous solids, yes the sintered filter will remove those kinds of particles, down to a certain size. I don't know how small a particle has to be to get through the sintered filter, but see on ScubaBoard that a regulator tech said it would protect down to about 5 microns. But it has to be fairly small, and there would not be a source for these small particles (other than rust). The Dacor Olympic first stage has a dual filter (two filters), the sintered filter than a much finer filter that will filter very small particles. Ten millionths of an inch is 0.254 microns. Industrial hygienists divide these particles into groups by size. These are: "Inhalable Particulate Matter," "Thoracic Particulate Matter," and "Respirable Particulate Matter." "Inhalable" means it can get into the mouth and trachea, "Thoractic" means that the particles are smaller, and can go down into the larger branches of the lungs, and "Respirable" means that particles are small enough to get into the gas exchange regions of the lungs. If a particle is smaller than 5 microns, it can get into the air sacs of the lungs. But those particles would be filtered out of a scuba system by the compressor's filters. It would be very difficult to get particles that small into the lungs. Gases are a different story, which is why many divers are now independently testing their air for carbon monoxide gas. This gas (actually all gases) cannot be filtered by a particulate filter such as the regulator's sintered filter. 'Sorry if I put too much information up, but I wanted to dispel what I consider a myth about hazardous components. Note that I put the definition of the TLV-TWA into the previous post. John
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Post by nikeajax on Feb 28, 2014 18:00:46 GMT -8
John, yeah, you're right, what I meant was chemical hazard. One of the things about being dyslexic is that you use the wrong words A LOT, and people often think you're stupid because of it. Most of the time I don't say anything to people and just do my thing, letting my work speak for me. As I've said before, it's a very harsh mistress to have...
Jaybird
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