I can't remember whom asked last night (Dan, GP??) at the gear night at SD&T, but the stuff you want to spray on your tanks where the paint has scratched off to the bare metal is cold galvanizing compound in a spray can, available at Ace Hardware (it's also known as rustoleum). Just remove most of the external rust, and put two to three coats on - it won't look pretty but it'll do the job.
Hope this helps,
David.
Great, thanks for the tip David!
Well, I ended up scraping off all of the bad paint/primer from the boot area of the tank as I could with a razor blade (talk about a PITA :
) I then wiped the scraped area (bare metal) down with a product called Exrust which dissolves any surface rust. Then I rinsed with fresh water, dried it good and then sprayed on the Rustoleum "cold galvanizing compound". I'm thinking this will be a good temporary fix for the year until I eventually get the whole tank sandblasted. Once I do that I'll probably just spray the cold galvanizing compound on the whole tank rather than paint it again.
BTW, does anyone have any recommendations on who to go to locally for an exterior sandblast? I know there are several sandblasting companies but which ones do scuba tanks?
Thanks
Try contacting this company:
This is a local company that does hydro tests, tank painting, internal and external bead blasting, etc. to all kinds of cylinders. I've found that their prices are pretty low too.
Let us know what they had to say.
John J
Thanks John. I did call them. I was told they don't like to blast and paint scuba cylinders anymore because they had too many complaints on how well the paint holds up. He said they would blast the tank for me though for like $7.50 which is a pretty fair price in my opinion. I think I may just get it blasted and then just go ahead and spray the whole thing with a few coats of the cold galvanizing compound myself. Touchup will be easier with the cold galvanizing than with paint.
I'm not sure whether I would blast the entire tank if you don't have any rust. As long as the paint is in good condition and you're not down to the bare metal I'd leave it untouched, and just fill in the scratches with the compound. AL cylinders is a whole different story...
Good point. I'll probably just hold off on the full sandblast until next year. I got all of the bad paint/primer off that I could so no point in removing the rest of the paint unless it goes bad as well. Besides it just had a hydro and visual so I'd have to get a new visual sticker as well as buy new nitrox stickers which are grossly overpriced. :
Wow! only $7.50 to blast the tank! I'll have to keep that in mind. In the past I have spent hours cleaning up old steel tanks with wire wheels, paint stripper and sandpaper. Big pain in the butt and it makes a big mess. I'd gladly pay $7.50 for someone else to do it and I'd bet they'll do a really great job too.
That's the trouble with tank boots on steel tanks. I bought some new OMS steel tanks several years ago and even though I knew better, I put tank boots on them. The boots are really handy because they allow the tank to stand upright of course, but in less than 2 diving seasons, the tanks were completely rusted under the boots, even though the paint looked excellent in other areas. When I took the boots off for annual visual inspection, the paint just fell away revealing rusted and pitted metal underneath.
If the rust is really deep, you should bring the tank in to a good visual inspector because there is a spec for maximum external pitting due to rust. If the rust gets too deep, it thins the tank walls significantly and can create an unsafe condition. How much pitting is allowed depends on the kind of tank and the manufacturer.
A suggestion...When you paint the tank, get a junk tank valve that you don't care about and install it with an old, used tank to valve o-ring. Then hang the tank from the valve using some wire or a hook and paint the tank. If you use a junk valve you can get overspray right on the valve and not even worry about it. You can even put a few PSI of air in the tank to keep paint fumes out, but I don't always do that.
gp,
why don't you wait until spring of next year and we can rent a sandblaster. i have 4 steels that i would like to blast. i know you can rent them fairly cheap. I'll bet there are others that would like to do the same. its an option. I know sandblasters are faily easy to use. i've used them to remove old paint on brick buildings. the only bad thing is the sand. We could do it up at my parents house in White Bear Lake, they have a bunch of land. later jason.
Thanks for all the tips guys. All good options to consider. I've done a little research on the blasting as well and I guess that using a nutshell media is best for sandblasting tanks as it runs less risk of taking off too much steel. I guess when sandblasting with sand you have to be careful not to leave the gun on one spot for too long.
John, my corrosion on the tank is exactly as you described. It's only in the area where that damn boot covered the tank. I'm throwing those boots in the trash. >
It is nice to be able to stand the tank up but since it causes corrosion I'm not using them anymore. The corrosion must not have been that serious as it did pass hydro and visual inspections a short while ago.