External rust, stripping & painting steel tanks

[fgray1]

I just had the same problem and this is how I solved the problem
I removed the rust with a wire brush. and sanded it by hand with 400 grit wet sand paper. went to the local auto parts store bought plasti coat auto paint. Not enamal paint (oil base)
This is the paint they use to match the factory paint on the cars.
choose a color that comes as close to the tank color as possible.
I did about 7 coats of primer wet sanding betwwen each coat letting each coat dry completely before the next coat is added. Most IMPORTANT is all the rust must be gone. If not you will have a problem later. After the primer has dried completely I did about 7 coats of the main color also wet sanding between each coat so as to get good adheartion to the previous coat. When your all done painting let it set in a warm place for at least a week to dry completely. After that you can put the boot back on and if you did it right have no more problems. If you get nervous you can have the tanks Hydroed again. Thats what I did. But the bottom of the tanks are the thickest part of the tank. As long as you only wet sand and wire brush the tank and there are no deep pits you should be fine. DO NOT USE ANY POWER TOOLS ON THE TANK. NO GRINDERS OR POWER SANDERS.
Remeber always remove the boot after diving and rinse and dry the tank before storing it. Leave the boot off if possible till the next time you go diving. The rust was caused because the boot was not removed.

 

[mrducks]

are u diving in fresh or salt water with your home paint job?

 

[totterfield]

I just had the same problem and this is how I solved the problem


How long ago did you make this repair job??? and it`s worked fine you say.
After you`ve used the wire bruch and wet sanded it, would you use like a rust killer to make sure or is this not nessesary?? cheers again
Tom

 

[fgray1]

I did the repair June 03 I dove salt and fresh water with them.
I've had no problems but I remove the boots and dry the tanks now. The paint from the Auto parts store is poly coat mixture if I'm not mistaken. Make sure all the rust is gone before you start painting. It took me about 2 weeks to do the job right waiting for the coats of paint to dry completely before the next coat was added. Total cost of the job was about $20 for paint and sand paper . Then just for peice of mind I had the tanks hydroed again and they passed with flying colors. These were my first tanks I did so I did alot of research before attempting it. I first tryed enamel paint but it never got hard or dried competely. In the sun it would soften up from the heat so I figured that would be a problem. I redid them this way after more research. I did read were someone used epoxy based paint (appliance paint) and had no problem with that. I decided for the poly based paint because it's what used on cars and I had more color choices. The best thing I can tell you is do alot of research and make up your own mind as to what makes sense to you. You can tell hows full of it when you read the post.

 

[fgray1]

I did'nt answer about the rust killer.
I did the firt try with enamal paint but I thought about it and changed my mind after I remove the enamal paint and redid them with poly. I decicded that if I used the rust killer again I maybe might get lazy and not remove all the rust and I was worried about the paint sticking to the rust killer so I just made sure I removed all the rust and started with a nice clean surface. I figured if It chips or I scratch it it's an easy repair as well this way.

 

[FredT]

Instructions are here:

http://www.scubaboard.com/t34414/s.html

FT

 

[northcoastdiver]

I'm in the process of removing the paint from my old steel 72. The paint is coming off good, however a grey coating is also starting to come off. Is this the galvanized coating, or could it just be a grey primer or something like that? I'm not using any abrasives, just an aircraft grade paint remover.

 

[Rick Murchison]

I don't know about every zinc application process, but hot dipping isn't susceptable to removal with paint stripper. It's probably a primer.
Still, I'd keep a mighty close eye on it for rust.
Rick

 

[northcoastdiver]

You were right, it was primer. I thought I was going to get off easy with this one, because the paint came right off. But now the primer is coming off VERY slowly with the stripper. I haven't tried using a wire brush or anything else, I guess I'm too worried about taking too much off. There's a pretty good galvanized coating underneath, and I don't want to mess it up. I wish whoever painted it in the first place would have left it alone.

 

[gto1]

PUWDER COATING steel tanks any thoughts?