Scratched painted tanks

[TSandM]

Did a search, and couldn't come up with much . . .

My beautiful white 85s are beginning to look a little battered. Is there any reasonable way to repair scratches in the paint before they become rust pits? I was thinking of automobile touch-up paint, but I'd assume I should do something to clean the metal before I paint it, lest rust progress beneath the new paint. Advice? (And don't tell me to buy galvanized tanks -- I've already GOT these!)

 

[DA Aquamaster]

Theoretically removing the rust is preferred, then coating with a cold galvanizing type primer, then applying touch up paint to the scratch. Removing the rust can be problematic without also removing more paint so proceed carefully.

 

[TSandM]

What do you recommend for rust removal? Will steel wool be enough, or do I need to use something chemical?

 

[Jim Lapenta]

Unless you have proper protection stay away from chemical removal products. We do touch up all the time on powder coated parts using automotive touch up grade paint over steel and aluminum. Your best bet is to use some 80 grit sand paper to remove the heavy stuff then a little 150. You can follow up with some scotch brite pads depending on how big the spot is. What you need to do unless you don't mind them looking a little weird is make sure you get the right color white. Otherwise the repairs may stand out more than the nicks. Until I started this gig I did not realize that there are literally dozens of whites, blacks, reds, and all the other colors. Choose the wrong white and it will look like some kind of skin condition. I would also advise against using steel wool as the fibers may actually come apart and get lodged wher they don't need to be. If this happens they in turn will rust and make the repair area even bigger down the road. So after sanding and scotch briting be sure to clean the area with something like a lint free cloth and alcohol or laquer thinner and then blow if off good with compressed air. then do the touch up.

 

[Stu S.]

The Faber 85 is easy to dive with. Hardly feels like you have it on.

I had a white 85 get knocked over and roll down a driveway. It held up better than expected. The few breaks in the coating that turned to rust showed up as a stain on the paint around the bare spots, so it looked worse than it was.

I used the point from one of those mini Swiss Army knives to scrape down to clean metal. Scotch Brite cleaned off the little stain. Using a small brush, I applied rustproof primer that I first shot from a can into the can's cap. I let it sit a couple of days. A few shots of Krylon interior - exterior paint at close range (practice this a bit first) covered the primer and looks like a fairly good match.

This was quick, fairly easy, and there's no sign of returning rust. It was about eight little spots, and the whole job took about half an hour.

By the way, my Faber 95 has taken a real beating, and remains unblemished. The 85 is easier for me to dive with.

 

[spectrum]

Until I started this gig I did not realize that there are literally dozens of whites, blacks, reds, and all the other colors.

Very true and a pure white is almost useless as a finish. A little blue and it's brilliant. Add a little black and it hides imperfections. But that's not why I'm posting.

If you do this and do a color check be sure to check it after the paint is dry as the color will shift to some extent. That's why you often see a blow dryer at a paint matching counter at the hardware store.

Pete

 

[DA Aquamaster]

If you are really concerned about matching the color, you can scuff sand the whole tank after you have cleaned/painted/filled the scratches and then just spray the whole tank.

The down side is that I have yet to find even a commercial epoxy paint system that is as durable as the triple sprayed finish Faber uses, so over time, you will have white scratches showing through your potentially different white coat of new paint.

If the goal is rust protection, touching up with a hobby brush or small airbrush is fine.

 

[TSandM]

I'm really not concerned as much with how they look as with protecting the steel from rust. If the paint doesn't match perfectly, that's okay. With my blue and white dry suit and red-orange wing and bright orange gloves, I'm a walking Rule 6 violation, anyway.

 

[crlavoie]

I'm really not concerned as much with how they look as with protecting the steel from rust. If the paint doesn't match perfectly, that's okay. With my blue and white dry suit and red-orange wing and bright orange gloves, I'm a walking Rule 6 violation, anyway.

If that's the case, it may be your best bet to just leave it. Without killing you with details, the majority of "average" industrial coating systems are designed to conform to an ASTM standard of 1/8" rust creepage for scratches or surface voids penetrating to the bare substrate. More advanced coating systems conform to an even higher standard of 1/32" or less with some systems being 1/64" or less. So, assuming your tanks are from a reputable manufacturer and were properly pre-trated and painted, you probably don't have to worry.

Aside from that, there is no way of addressing these scratches with any longevity without a lot of hassle and specialized gear. Trust me on this.

Oh, if you do decide to give it a periodic touch up for asthetics, do not use steel wool. Stick to scotch brite pads or aluminum oxide sand paper. Give it a good cleaning with Simple Green and a shot of the best zinc based primer you can find.

 

[TSandM]

Thanks. Then, if there's no significant worry about the tanks corroding because of the scratches, I won't do anything about them.

The tanks I saw in Cozumel scared the dickens out of me with regards to corrosion and pitting of the outside, and I don't want to lose my tanks!