What I did under my truck cab was apply Por-15, waited awhile until in tacked up, then applied a few coats of Wurth rubberized under coating.

I plan to do that with the rest of the underside of the truck.

However, I may try Zero-Rust instead.

If you don't seal up the Por-15 container tight, you will have a paper weight.

 

i don't know what it is but i got some stuff from my grandpa that we got from his work (military paint) and this stuff is tuff and stops the rust

 

raceman351W, what is the stuff?

Any name(s) on the container?

 

From the research I've done:

di-isocyanates are the dangerous ones, simple "isocyanates" are not.

Also, Rust Bullet started out as a military rust stopper/preventative...according to what I've found...it may be that raceman351W's stuff was Rust Bullet.

Finally, I learned a little trick to prevent you from ending up with a POR-15 (or any other canned chemical) papper weight. Don't take the lid off the can, simple as that. Instead, put a sheetmetal screw in the top center of the lid, and one at the bottom on the side of the can. When you remove the screws the POR 15 drains out the bottom hole, sucking in air via the top hole. Replace the screws and give the can a shake. The POR 15 seals around them, but doesn't allow the whole can to be exposed to air, and you never have to worry about making sure the can lid is on tight. As fair warning, I haven't tried this one myself, yet...just ran across it the other day, but the logic is sound.

 

I used Rustolem Damp Proof Red Primer and the black topcoat on the bottom of my 51F1 cab. Then went over it with herculiner bed liner coating to make it quiet. That was two years ago and it still looks great I have had no problem with it. I think I put some pictures in my gallery if anyone is intrested. I have also used POR15 under one front fender as a test to see how it will hold up, I put it over the Rustolem primer and so far I see no signs of failure. It's just expensive at 35 bucks a pint and messy.

Rod 51F1

 

I've used POR-15 and it works well. But as previously mentioned it's a pain to worr with. And the biggest issue (to me) is, it's damaged by UV so you have to paint over any part of it that is regularly exposed to strong sunlight.

 

i don't know what it was. we did it like 6 years ago it maybe rust bullet but thie stuff was military green and then i painted over it with black spray paint. but now i get to have the fun of taking all that off, my dads work just bought a powder coater so that is what i am going to do now

 

Is Zero-Rust a similar product to Os-pho? I have a container of Os-pho that I bought to use on my old Econoline in some hard to reach places. Directions say to brush it on and let dry, once dry you can paint right on top of it. Any experience with it?

 

No, Zero Rust isn't like Ospho. Zero Rust is a really tough paint.

Ospho is a metal treatment that chemically alters the top layer of any rust it runs into, as well as the surface of the metal. It is a paint preparation product...think of it as a mild cleaner and surface preparation tool. Ospho has phosphoric acid as one of the active ingredients, just like many "rust buster" type treatments.

Those products are good for what they are designed for, which is to zap any small micro rust that is left over after you've removed every possible bit of rust you can see by sanding, blasting, or brushing. They are not a short cut to save you the work of trying to strip the rust first. They do "turn the rust black", but underneath that black surface the cancer is still there. If air and water get to it, it will start eating away again.

Por-15, Zero Rust, and Rust Encapsulator are all really tough paint products that are designed to make it virtually impossible for air and water to reach the metal and any remaining rust. They really like a rough surface (such as rust) to cling too. However, if you don't strip as much of the rust as you can, it's kind of like putting seeds in the ground, then trying to cover it with plastic to keep weeds from growing. Yes it sometimes works, but the right way to do it is to get the darn seeds out!

Here is the not-so-secret checklist for rust removal and prevention:
Strip it to bare metal, Chemically treat, degrease/clean, prime, paint

 

Zero Rust is chemically designed to bond with rust at the microscopic level; this isolates the rust from the air so it can not spread. Their instructions state that painting over new or blasted clean metal is not what it is designed for. To do that properly you should use their Prep Step which is a mild phosphate and etches the metal. Read their web page and links to see the development of ZR for marine use. Their parent company, Amteco, is a large speciality coatings company that has been around for decades.

POR-15 in its original form was nothing but a renamed/repackaged industrial floor coating. It simply covered the rust and DID NOT chemically bond to it. Their later formula is even less effective without buying other products to prep but I understand it was a legal matter that forced the change.

Rust Bullet is another clone of POR-15. Easily damaged and very hard to repair. IMO a total waste of money. A principle was on HAMB a few years ago making claims about Navy testing. The ZR VP of Sales showed up and challenged his claims. RB folded up his tent and snuck away with his snake oil.
HAMB is probably the most watched automotive forum site in the world by industry, magazine, and professionals. Nothing escapes scrutiny and phonies die a horrible death! Ive been on HAMB since almost the beginning and the technical content and member expertise still amazes me.

 

They don't mince words, either!

 

That's exactly what how I used Zero Rust on the floorboards of my Mustang and it worked great! The mild phosphate/etching step is what I meant by "chemically treat", BTW.

A wire brushing will never get every bit of rust off the way blasting will, but I came pretty close in about 5 hours of hard work on the floorboards. Zero Rust sprayed from a can stuck very well to the bare metal on those floorboards, following the recommended phosphate/etching and cleaning. It's good stuff!!

286Merc, I respect your opinions and I'm curious: Do you believe Zero Rust painted over the surface rust on the floorboards would have been a better solution than painting Zero Rust onto properly treated (phosphate/etched)bare metal?

 

I'm curious, if you do sand blast, then acid etch, you can use Zero Rust? How about epoxy primer over that?

 

ONLY IF all the LOOSE rust was completely removed. This is often very hard on floorboards when you cant get a wire wheel or disc into every spot. Prep Step can also be used to loosen rust and then wire brush.
My first time using ZR was on my car trailer 6 years ago; I built it in 1970 so it sort of needed attention! I used a combination of dust blasting and wire brush and shot it with 3 coats of ZR Red Oxide, never finish coated it as it does serious work and its easy to touch up. Not a trace of rust has returned.
I now use it on all sorts of projects, customer or personal, home or shop. Even did some of my own tinting for a exterior finish coat.


52 Henry:
Yes you can to all. But if you do a complete blast to white then the Prep Step isnt necessary as the surface is plenty rough enough for adhesion.
But since Prep Step is so cheap and you can paint right over it, it certainly cant hurt and besides it prevents flash rust.
Since ZR is an alkyld based paint containing acetone and xylene ( in spray cans) I use a sealer before applying a regular top coat. When doing a regular HVLP spray job I thin ZR with a painters grade of lacquer thinner.

 

Rust-proofing paint is good but it is only as good as the conditions permit. In body areas where there may be rock chips, etc you may want to consider something more durable like the products they use to coat the inside of the truck beds. Herculiner is a good DIY product that will adhere well and resist the chips that espose bare metal to the elements.