I have an old claw-foot tub that’s totally rusted on the underside … can I use a product like POR-15 to paint over the rust without removing it? I don’t want to spend big money on this but I want the paint to last …
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The rust-reducing paints and primers (not familiar with POR-15, so don't know if it's in that category) work quite well. They interact chemically with rust to form a strong bond. They don't generally produce a very smooth finish, though, if that's a consideration.
I will be painting a color over the treated surface -- but if it's really rough it won't look good on a bathtub! I suppose the smoother you can get the rusty surface the better the finish? Or does the rust-killing process make it rough looking anyway?
First off, the rust-reducing paints/primers need some rust on the surface to adhere -- they don't adhere well to rust-free metal.I can't say for sure that they make the surface any rougher than it was to start with, but they don't make it any smoother, and the paint is very tough and hard to sand.
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That's not a problem -- it's solid rust! Thanks for the advice ...
Yea I've used POR-15 and it works as advertised. Just follow the directions-scrap off the loose rust and make sure its clean (as in not greasy-dirty). The stuff turns milky in sunlight but thats probably not going to be a problem on the bottom of a tub
Daniel Neumansky
Restoring our second Victorian home this time in Alamdea CA. Check out the blog http://www.chezneumansky.blogspot.com/
Oakland CA
Crazy Homeowner-Victorian Restorer
Try 'Hammerite' paint, designed specifically for what you are talking about. Probably about $65 a gallon, but you could probably do with a quart. Comes in a smooth glossy finish or a 'hammered' finish. Fumes are not so nice, unless of course you are like Raymond's father and like the smell.
Let's not confuse the issue with facts!
I almost used hammerite on a painting project until I learned that no other paint will ever stick to it. Apparently it has a very high silicone content and that prevents other finishes from adhering to it. Other than that it sounds like it does a great job.I think rustoleum red rusty metal primer does a great job. I use it for all kinds of projects mostly because I like the color of it for the final finish. I wish they made a paint and not just a primer in that color.karl
re Hammerite - Krylon and/or Rustoleum makes that stuff in a spray can, & it is DYNAMITE on the underside of tubs, cast iron sinks, & radiators.A bathtub takes one can - $7.95, tops.
That would work pretty well if you are putting it out in the horse paddock for a drinking well for the critters, but for something you want painted nice for in the house, roll it over and spend an hour with a wire cup brush on a drill motor.
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I would first try to remove / smooth the rust. I've had real good results using a Scotch-brite pad on an orbital sander.
The next step, IMO , is to use one of those 'rust reformer' products, rather than a primer. These products take a few days to properly act, and leave the surface looking a dull black.
After that, it should paint real well. I would suggest that you try a new technique; thin the paint, and daub it on with a paper towel. Prior to painting, you might even MILDLY heat the tub, so it feels warm to the touch. This will help the paint soak in, as well as help prevent runs.
What I have done, with good results (tub looks great after five years) is wire brush and sand exterior of tub, bondo, prime and paint with oil base.
Please excuse my ignorance -- if the bottom of the tub is solid rust, is it necessary to use one of those rust converting products to stop it from further deteriorating or would sanding, bondo and paint work just as well in the long run?
The rust-converting products avoid the need to get down to bare metal, and they bond well. If you don't use one then you need to get down to bare metal somehow, then use a good metal primer to assure a good bond.
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Just a general FYI, POR15 has as part of their portfolio a rust converter called Metal Ready, and it works great. I will never ever use navel jelly again.Rebuilding my home in Cypress, CA
Also a CRX fanatic!
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