TheSamba.com :: View topic - SEM Rust-Mort and Rust-Seal.....any good?

Wed Jun 14, 2006 5:49 pm

This is the stuff the local supply store reccomends. One you have to prime afterwards and one you don't. Which works better for seam rust or should I go with something else. I hope to start this weekend and don't really want to wait for something else to ship......but I want it done right.

Thu Jun 15, 2006 9:10 am

I've used both Rust-Mort and Rust Seal with mixed results for both.

They seam to do a fair job of converting the rust, but they tend to leave and undesireable, goo like substance on the surface that is a real pain to clean off. This has happened to me more than one time, so I gave up using it.

Skyco makes a product called OSCO. You can purchase it at the hardware store like ACE. It's similar to the Evapo-Rust. You just apply it to the rusted areas and let it dry. OSCO leaves a slight powdery like substance on the surface. It can easily be removed by a light wire brushing and cleaning with wax and grease remover.

If Rust-Mort or Rust Seal is all that you can get, you should be able to make it work and get satisfactory results. I just feel that there are produsts out there that are easier to use and give better results.

If you have a choice, Rust Seal would be my first choice of the two options.

Thu Jun 15, 2006 9:27 am

I'll check for the OSCO. So after you use it just wire brush/sand and prime?

Thu Jun 15, 2006 9:49 am

Yep, exactly. Just be sure that the surface to be painted is clean with no wet areas or powdery substance on it.

If you use acid etching primer on it, be sure that you use really light coats. Acid etch primer is not meant to fill any imperfections, it's just meant to coat the surface and bite into the metal. If it is applied too thick, it can actually peel off, exactly the opposite of what it's supposed to do.

Also, don't use acid etch primer over any body fillers, it won't stick very well. If you have any body filler work to do in the rusty areas, the sequence should be treat all of the rust, treat the area with acid etch primer (optional but not necessary), grind the areas where body filler is needed with 36 grit down to clean metal, finish the body filler work and prime with epoxy primer.

Thu Jun 15, 2006 10:38 am

I don't have any body work near the seams. I just want to take care of the rust and replace the seems. Then it's off to MAACO (or equivilent $ shop) and have them take care of a few dents and shoot the paint. They just can't be trusted to handle rust.

Thu Jun 15, 2006 10:42 am

Have any of you heard of this stuff? I used it in the floor of my splitty and coated w/ Pitsburg paints epoxy and han no rest after 11 years.

use to be called MP-7....now its Must for Rust

http://www.tinmantech.com/html/faq__mp-7_must_for_rust.php

Thu Jun 15, 2006 11:41 am

I've personally never tried it, but if Kent Fuller endorses it, I would most certainly give it a try. Kent Fuller is one of the countries top metal men. I have the utmost respect for him and his work.

Thu Jun 15, 2006 1:23 pm

cool. It looks like I have two choices that I can look for in town.

Thu Jun 15, 2006 2:28 pm

What primer should I use? Any brands to stay away from? Also what should I use to clean the metal before priming? Will paint thinner work?

Thu Jun 15, 2006 4:45 pm

As far as spray can primers, I only have experience with U-Pol and RM brand primers. Working in a body shop, we don't use much in the way of spray can primers.

Both of those lines have both etch primers and filler primers. There is a new line of spray can primers out made by a company out of Germany called Spray Max. They have a two part urethane filler primer out right now that is supposed to be really good. Spray Max also makes all of RM's spray can items.

The only thing that I can say as far as what to stay away from is you get what you pay for. Stay away from hardware store brands, Rustoleum, Krylon, Dupli-Color, etc. These brands have their place and MIGHT work fine for you, but do you really want to go through all of the effort and money to find out that they won't? Besides, problems usually won't arise until AFTER the car is painted. Then you have no choice but to re-do everything. Not fun!

U-Pol nad RM brand spray can items are expensive but they are designed to be used in an automotive enviroment and are compatable with most mainstream topcoats.

Thu Jun 15, 2006 7:22 pm

I dont need much, just enough to cover the rust repair

Thu Apr 23, 2015 5:55 pm

Should I prime the bare metal first then use filler where needed then re prime?