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On Mon, 07 Aug 2000 15:57:17 -0400, you wrote: >>Date: Mon, 07 Aug 2000 15:56:47 -0400 >>To: vbtech@ci*.co* >>From: Charles Ayash <cagraphics@mi*.co*> >>Subject: Re:Tanks-Paint and Rust/ The Fix >> >> >> >>Rust >>3m Rust Avenger (3m#3180) list price 5.29 >>This is a pen type unit that also has an abrasion tip >>on the cap, that is used to scuff the loose rust particles. >>The pen is then used to apply a thin coat of liquid >>that stops the rust and also becomes a protective coating. >> >>Can be purchased at a auto paint and body supplier/jobber. >> >> >>Blasting a cylinder and new powder coating?? >>Al. cylinders or steel; IF blasted would be costly >>due to Glass Bead Blasting would be better than sand. >>By the time you powder coat the tank I think that >>a new Luxfer would be cheaper and Safer. >> >>A better method than powder coating would be to use >>an Epoxy Primer and Paint. So unless you are a Painter >>"ya gonna pay" someone to pull the trigger not to mention >>the cost of these paints. >>This is not cheap, as you have the cost of the Paint, Reducer,=20 >>and Hardner. This is not only cheap, it's dangerous. Back in the 70's, they got the same idea, only for the INSIDE of the tank.. they figured an epoxy liner would prevent corrosion inside steel cylinders. Problem was, the epoxy developed pinhole leaks, and the corrosion proceeded unabated beneath the liner, where you couldn't see it until it was too late. On tanks with an exterior coating of epoxy, you can at least see the corrosion when it gets bad enough to bubble the coating, but the end result it the same; the epoxy does not hold water integrity over any length of time, while it DOES tend to retain moisture, inducing further corrosion. A tank boot does the same thing, which is why you should not be using them in the first place.=20 >>After talking with a client who is in the powder coating business. >>Here are a couple of variables. Which Greatly depend upon the=20 >>Material, Casting Process, and Material Thickness. >> >>Aluminum baking temps will range from 320 deg-400 for 30-60 minutes >>Steel appx 400 deg from 2-3 hours and possibly a rebake for another = 2-3 hrs. >> >> >>Again I think you would save time and money by purchasing new. And don't put boots on the next set. >>Did I forget the Integrity of the Cylinder? Safty Safty Safty This needs to be said in much plainer language: HEATING HIGH PRESSURE CYLINDERS CREATES BOMBS!!!!! Heating can destroy the ability of a metal cylinder to safely contain the thousands of pounds PER SQUARE INCH of pressure the average scuba cylinder holds. The actual forces contained run to HUNDREDS of tons. Many retail stores refuse to fill ANY painted cylinder, because there's no way to verify whether the tank was painted with a simple spray can, or with a heat-baked method that puts everyone in the area at grave risk. >>I hope this helps a bit. >> >>Regards >>Charlie >> Hope this helps too.. at this point, if the rust has not compromised the integrity of the tanks, maybe steel wool & a lot of elbow grease to remove existing rust, then a clear lacquer reapplied at regular intervals, if you MUST use the boots. They're a poor substitute for a rack, a safety chain, or a strong hands-on, however. By the way, I didn't see the original thread..was this posted to cavers originally? >> >> >> >>At 08:18 AM 8/7/00 -0400, you wrote: >>>We had a group of individuals CA, FL, NY, & NJ joint us for the = weekend of >>>diving out of Virginia Beach (Trip reports to follow). One very = interesting >>>discovery upon removal of my tank boots was rust. >>> >>>Tanks: are SCUBAPRO steel 95s, white, and about three years old. >>> >>>Care: these tanks are VIP as required, washed off with fresh city = water >>>after every dive (even quarry/lake), and stand up in my garage when = not in >>>use. >>> >>>Result: The paint under the boots hass bubbled and formed pockets for = the >>>salt water to collect. I do not know if the paint and water react = under the >>>paint as it does in fiberglass boats or not to form an acid compoound.= I >>>hope someone out there, in the knows, has the answer to that. It has = cause >>>some extensive surface rust (already had two opinions from technicians= on >>>this). >>> >>>Several other sets of tanks have been checked and found to have = similar >>>conditions with different ages and manufacting date/group. OMS = versions, on >>>a limited check group, appear not to have this problem. >>> >>>If you have SCUBAPRO tanks with boots on, remove and check for rust = ASAP. >>> >>>Now what is the best preparation and painting to stop this and = preserve the >>>metal? >>> >>>David >>> >>> >>> >>><< Send subscribe/unsubscribe/help requests to >VBTech-request@ci*.co* >> >>> >>
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