Under tub spray

I'm looking for something easy and cheap to spray the underside of my tub. All in all it's in pretty good shape what isn't I'm fixing. I've heard of some types of paint that chemically change the rust to stop it from spreading thought that sounded interesting and or expensive. I would like to spray it on if possible love to hear some of your ideas.

 

how about bed liner for trucks, like the rhino liner?

 

I use Interstate Rust Killer. It "can" be sprayed on. You want to wire brush the metal first though and get any loose stuff off. I remove all the paint as well. That way the Interstate product can treat all the metal. Once that dries I paint over it or coat it with automotive undercarriage spray. The exception is the frame. I just leave the frame treated with the Interstate product. This is just the way I have found that suits me best. There are any number of products and methods of treating this issue. I like this because it is relatively inexpensive, works very well, is easy to maintain and is easy to touch up if you have to grind some off for welding or some such thing.

 

It's not cheap but I have herd good things about this product.


http://www.lizardskin.com/lizard_skin/recreational_vehicle_insulation.php

 

If you have surface rust, I expect you cannot use bed liner directly over it. Check the container - I think it will tell you to apply over sound, painted surfaces ... ie not rusty or bare metal.

For a rusty surface, there are chemical converters and there are encapsulators. The converters, like Naval Jelly or Permatex's stuff, change the oxidation state of the rust from red rust to black oxide. The black oxide is structurally better than red rust, but it's not very weatherproof. Black oxide should be covered with a top coat (paint) of your choice. Epoxy primer might be a good choice.

There are lots of different encapsulating paints, including POR-15, Eastwood, Rust Bullet, etc. These coat surface rust to seal out water and air, but do not convert the rust. They also draw water out of the surface when they cure, halting the rusting process. You must at least wire brush to a solid (but rusty) surface before applying these products.

 

Benjamin moore has a phosphoric acid "industrial rust pretreatment" M8400 that you can get at their home paint stores. If you clean off the dirt and wire wheel the rust, use the acid, prime with an good primer and topcoat - it will hold the rust back for a long time (unless you drive on salt roads). Treated the outside welding table that way and its still rust free after 4 years.
The bedliner stuff will hold in any water that gets behind it. That could be a problem.

 

All great advice my local autobody paint store is recommending a product called "Zero Rust" anyone heard anything good or bad? I really don't have that much rust and I will be able to remove almost all of it I am just really wanting to seal it up tight and stop what I can't or don't get out.

 

Heard of it - should be fine.