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Post by scubadiverbob on Aug 12, 2014 22:37:15 GMT -8
Don,
Where they put the hydro stamp, it's also rusting. I'd clean it up and use the paint John mentioned. The bottom, without actually seeing it, looks like it rusted through the paint and might be starting on the steel.
Robert
They pull the boots off here when they hydro tanks, and also stickers, in case there is rust under either. Found that out when I had a tank with still a good hydro (three months left), needed it to go diving; so, it got a new vis. After I got it back from hydro, the vis sticker was gone. There sent some more money!
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Post by scubadiverbob on Aug 12, 2014 22:40:16 GMT -8
Got to get some sleep. If my back isn't making weird cracking sounds, I might take Andrew to the river tomorrow. If it is making cracking or popping sounds, we still might go.
Good night!
Robert
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Post by tomcatpc on Aug 13, 2014 16:58:45 GMT -8
Here are two of them so far. The 1960s tank is the rusty one and the 1970 vintage tank looks all right other than faded paint. Mark
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Post by nikeajax on Aug 14, 2014 8:20:57 GMT -8
Hmmmm! Perhaps using some kind of chemical stripper, to remove the paint, then use a wire brush to knock the rust down. Try to find a some good primer and paint, either epoxy or urethane.
As for painting: start with a "tack coat". This is a fine misting of paint, you're not trying to "pull a gloss" yet... let that sit for a few minutes, about five. The HUGE mistake people make while painting is too heavy of an application; they put it on like they're shooting a flame thrower, saturating the paint and it runs and does all sorts of icky things, with the end result being a poor job. The best way to paint is to get about six to eight inches away moving in a back-and-forth motion: the trick here is to let up, stop spraying, after each stroke, and keep the nozzle MOVING--NEVER hover over a spot! This takes a bit of practice, but once you have it, you can learn to load the paint, which is what I meant by pulling a gloss: give it a few coats, waiting about 1/2 hour between coats.
I wrote the above earlier, so it may sound familiar...
Jaybird
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Post by tomcatpc on Aug 14, 2014 11:48:26 GMT -8
I think that the worst part is covered by the tank boot, when it goes back on. I think it looks a lot better in real life than it does in a photo. I can deal with the way it looks. I would however, address the rust spots and at least put something on them to prevent them getting worst. The darker yellow spots are coming off easy, and they cover smaller rust spots that someone just "gooped" that stuff on to cover the spots. I think this tank could look "acceptable" with a bit of work.
If it does look like heck...then I can attempt a re-paint. But first it needs to pass Vis. and Hydro LOL! It is fun to stress out over tanks that I got for free...I can deal with these sort of "problems" LOL. I'm grateful for things like this. Mark
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Post by nikeajax on Aug 14, 2014 13:21:28 GMT -8
"It is fun to stress out over tanks that I got for free...I can deal with these sort of "problems" LOL. I'm grateful for things like this." That's the spirit lad! What if you brushed the rust out, and then used some paint to quickly cover the rust, stopping it, then see if it passes its hyro and viz... Jaybird
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Post by SeaRat on Aug 14, 2014 13:49:57 GMT -8
"It is fun to stress out over tanks that I got for free...I can deal with these sort of "problems" LOL. I'm grateful for things like this." That's the spirit lad! What if you brushed the rust out, and then used some paint to quickly cover the rust, stopping it, then see if it passes its hyro and viz... Jaybird That is what I would do, wire brush, very light sanding, and some primer + paint (spray cans) of a zinc paint (yellow ). Then see what happens. You can hold it a bit, and only have one tank in at a time for hydro. You have a cross-over manifold, so you can put that on a tank with pressure, hook it up to one of these tanks, and then put a few hundred psig into the tank to ensure no further rusting on the inside too. When you get one back, hopefully passing hydro, then you can go from there. But don't spend needed money on all the hydro's at once. Get one tank up and running, then take some time about the others. John
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Post by duckbill on Aug 14, 2014 16:16:31 GMT -8
The darker yellow spots are coming off easy, and they cover smaller rust spots that someone just "gooped" that stuff on to cover the spots. That's about what happens to paint when rust forms beneath it. The rust forms, bubbling and discoloring the paint. What you may have is orange caused by rust beneath the yellow paint, which looks thicker because of the bubbling underneath. Hard to tell from the photos, but that would be my guess. If you're uncertain whether these cylinders are good enough to pass or not, I would ask for a quick visual before committing to a hydro. If they say "these would fail visually", then you always have the option to get a second opinion elsewhere before risking the tanks being condemned. Our local LDS won't pass a cylinder if it has ANY orange in it at all. ANY Joe Blow can inspect and pass a spotless cylinder. Big deal. It is pitting that ruins a steel cylinder, not light flash rust. Needless to say I saved my cylinders by finding some place that had enough training and confidence to differentiate between normal flash rust and actual pitting. Even a certain amount of pitting is fine, and it takes some training to know when to say when. Visuals are pretty subjective, and the true dividing line between pass and fail is open to interpretation.
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Post by nikeajax on Aug 14, 2014 16:44:48 GMT -8
DB, you've been hiding and waiting to pounce eh? Both of you last two posts have been excellent: thanks for your input! Mark needs good advice like this, and I learned it a bit painfully This is why I suggest a fire extinguisher shop. There are a lot of really good dive shops out there, but some leave so much to be desired... the one bad apple, as it were! Jaybird
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Post by tomcatpc on Aug 14, 2014 18:13:25 GMT -8
Ok...I have seen paint with rust under it and has affected the paint. This is clearly a substance that has been applied to keep the surface rust in check. I'll have a go and try to take a photo. The other two tanks are rust free (externally), so I'll try and get those checked first.
And the one tank with the surface rust is just that, surface rust, no pitting. Just places where the coating/paint got scraped off and the outer surface of the steel oxidised. I think this can be sorted out fairly easy?
Can Fire Extinguisher Shops perform a Vis. Check on Tanks? There was one place in Toledo, Ohio here that does Hydro. testing for paintball...I sent an Email and all they do is the Hydro, no Vis. check. I totally agree with staying away from Scuba shops in this case. Yes, I totally understand that they need to make money...I get that, but if I can get around the sales pitches about "you just need a new tank" etc., then I will. Mark
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Post by nikeajax on Aug 14, 2014 18:32:18 GMT -8
Mark, only the dive shops do the viz and give you the sticker The hydro place does all the work for you tumble etc. and the dive shops puts their little flashlight down the bore and sez, yeah, or neh... at least all of the ones I've been to... Jaybird
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Post by tomcatpc on Aug 14, 2014 18:55:44 GMT -8
Ok...that is what I wanted to know, but was scared to just come out and ask LOL (well not really...but hey LOL). I have faith that these tanks will pass Hydro...the Vis. inspection is what I'm concerned about. Too bad there was not a person in the "Local Vintage Scuba Community" that could do Vis., it would be totally awesome to have someone sympothetic to our cause (LOL) and was not into selling brand new kit LOL. Mark
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Post by tomcatpc on Aug 14, 2014 19:02:52 GMT -8
More interesting extremely new diver questions... I am thinking positive and going on the notion these tanks pass. Two of them have J-Valves, which I plan on keeping and using. Now to keep this thing "stock and correct" I need to find a Pull-Rod for the valve right? Also, is there a band or bracket that secures the Rod along the side of the tank and not swinging all over? Mark
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Post by duckbill on Aug 14, 2014 19:11:33 GMT -8
DB, you've been hiding and waiting to pounce eh? Both of you last two posts have been excellent: thanks for your input! Thanks, JB. I have been pretty inactive here for a while. You guys always have the bases covered so nicely that I hardly ever have anything to add. Mark, a visual is actually very much a part of every valid hydrotest. Every hydrotester must visually pass a cylinder along with a passing hydrostatic test for the cylinder to be requalified. I. too, have never seen a hydro facility give out stickers, but technically the stamp on the cylinder IS also a visual stamp, good for five years. It's only the scuba industry that self-adopted the annual visual. So, really, since the stamp on the cylinder already has a visual covered at the hydrotest, you'd think a scuba shop would waive the sticker bull for the first year, but dive shops like to cover their rears because the cylinder comes from the hydro facility unpressurized, and anything can happen from that time until the valve is installed and the cylinder pressurized. In other words, the sticker is proof to other dive shops that the cylinder was re-visually checked immediately prior to being pressurized. To answer your immediate question, a hydrotesting facility is more than qualified to give your cylinders a quick visual before you authorize the full hydrostatic test. They can advise you whether they need whipping or tumbling before they are hydrotested. That's not to say, though, that your LDS will agree with their visual evaluation (like I mentioned in my previous post). That's the only reason why it might be better to have the LDS look at the cylinders first, but they might charge it as a visual, then charge for another visual after the hydrotest.
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Post by noneedforaname on Aug 28, 2014 15:33:57 GMT -8
I would not worry too much about the tanks, if they had air in them they will probably pass a hydro. I have bought around 12 72s and 3 80s every one of them has passed
For the j valve rod question a lot of the back packs have a slot to put the rod in. I however do not use the rod I just wear the pack loose and kinda flop the tank up and just turn the valve with my hand.
The rod definitely makes it much easier to double check to make sure you haven't accidentally bumped the j valve though .
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