scratched bottoms of double steel tanks

[jenkkij]

Acquired doubles from a cave diver. See the attached image. the bottoms are bootless and scratched.
What can be done? Steel brush, wet sand, clean, clean, dry, dry and paint with clear epoxy paint to monitor the metal? Any suggestions/comments on the method to proceed. Should I even try to touch them up? Just want to stop the rust/protect and keep diving. I don't need pretty tanks just safe equipment.
I have see some threads about painting but thought I would show the picture and ask the question again. Thanks

 

[spectrum]

In the picture it looks like the galvanized finish is hanging in there with no real rust showing. Do not sand or grind since this will remove any remaining zinc finish.

I'd wirebrush, then use a cold galvanizing primer and some sort of finish paint on the bottom. I wouldn't paint anymore than needed, tape it off and go 2 tone.

If they are truly galvanized then doing nothing is a very real option. If they will continue to be used sans boots paint won't last for you either.

Pete

 

[dbg40]

Are they galved? If so, strip the paint off of them, as they should'nt be painted anyway, and dont worry about them. If you keep the boots off, they'll be fine. Sooner or later, most steel tanks get a tiny bit of pin rust on the outside, if you don't let them sit in a wet environment, and let them dry properly, you won't have any trouble with them.

 

[skinerd]

What he said. eace2:

 

[Mark Vlahos]

I had a pair of Faber 95's that were doubled for a while and the bottoms looked pretty much like those in your photo. If you will continue to dive them in fresh water, I would not worry at all and just keep diving them. If however you will be diving them in salt water and the scratches go all the way to the bare metal I would recommend the following action.

1 rub the cylinder bottoms with a "ScotchBrite" pad until all rust is removed, and you have a good looking transition from the clean bare metal to the painted areas. You want the transition to be smooth, no layers of paint to chip off later.

2 paint with a good paint. I got some grey primer from a car parts store, you know the kind with a little brush in the cap. Follow the directions on the paint bottle. I would not use spray paint, stick with the brush on stuff.

Please note, only do steps 1 and 2 if the bare metal is showing. If you actually have any rust discoloration this is a good indication that the coatings have been damaged all the way to bare metal. Like I said at the beginning, if you will dive them in fresh water, just keep diving them.

Mark Vlahos

 

[jenkkij]

Thanks for the comments. I think I'll leave the scatches alone for now. Making sure the bottles are rinsed and dry after each dive. Just monitor the situation.

 

[jenkkij]

So I dived them this summer without doing anything. Had boots on and off at various times. Putting them away for the winter I noticed some rust. Guess now I have to touch them up. Any ideas about how to make a clear coat repair so I can still see the metal?

 

[dbg40]

how much rust? if it's just a bit of surface rust, don't be too concerned. just keep them in a dry place, no moisture, no rust. If you feel you have a need to coat them, we nave a product here called chip guard, that is available at most auto part stores. It's basically a very heavy tough clearcoat in a spray can. If it were me, id leave them alone.

 

[captain]

I have a bunch of galvanized 72's from the 1960's and 70's that have never had boots and are still just fine. Boots do more corrosion damage than they prevent.

 

[jenkkij]

the rust is minimal but noticable. I would not use boots if it weren't for the fact that all my dives are boat dives and they transport better for the 40-50 min. boat trip to the dive sites. I will leave them alone for now. if things progress I'll head to the auto paint store and browse what they have up here in finland. thanks.