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-   -   What are the best chemicals to use for removing rust? (https://www.rx7club.com/1st-generation-specific-1979-1985-18/what-best-chemicals-use-removing-rust-408922/)

boog 03-27-05 11:45 PM

What are the best chemicals to use for removing rust?
 
1 Attachment(s)
What have you guys used that you love, can chemical really eat away the rust and leave the metal alone? I put in a pic so there is an idea of how much there is, the very front and back is the most major spots and then its sporadicly everywhere else.bummer........God bless

Rx-7Doctor 03-27-05 11:59 PM

Rust
 

Originally Posted by boog
What have you guys used that you love, can chemical really eat away the rust and leave the metal alone? I put in a pic so there is an idea of how much there is, the very front and back is the most major spots and then its sporadicly everywhere else.bummer........God bless

Looks like basically surface rust. Recommend naval jelly. You can also use a siphon feed sand blaster if you have a compressor. Anothe option is to use permatex's
rust treatment. It turns the rust into a black primer that can be painted over. rx7doctor

mortenf 03-28-05 02:40 AM

I dont think there are any shortcuts to a rust free RX. Products like "rustaway" and so on only covers the rust for a period of time. The only way you can really get rid of rust is to sand the affected parts down to bare metal, and then apply some sort of rustmilk.

You see, sanding and blasting rust away leaves a rough surface that may be looks clean and rustfree, but its not. There are still tiny bits of rust in the metal, and if not treated right, it will come again.. This is where products like rust milk are intended to use. Once down to what appears to be metal you apply the milk (its called milk at least over here in Europe) and it will chemically mix with the particles that are left. They were never intended to do whole sheets of infected metal, and tough they will turn it black, thats only a temporary.

So in short, there is no shortcuts, the right way is to get yourself a sander, angle grinder or sanding paper of some sort and start sanding/grinding that rust of!
Then, apply the rust milk, let it work, and primer it with a good quality primer. For underbody rust prevention, it could also be a good idea with some more protection. We use Tectyl, but you can also go the Redneck route and use engine oil, mixed with sand (actually works!)

The absolute best rustmilk out there, is in my opinion Wurth`s. Its costly, but you get what you pay for.

trochoid 03-28-05 05:04 AM

The only way to remove rust is by abrasion. Grinding, sanding, or sandblasting. Once that is done, the remaining rust needs to be converted. I use Rust Converter from WalMart.

Your .doc didn't show up on my comp., so I have no idea what you are working on.

The proceedure is to remove as much rust as possible, convert it, then use a top quality sealer. Primer and paint follows that. Do not use a standard primer over the converter, it will absorb moisture from the air, when you paint, you will the seal the moisture in and it will rust through.

RexRyder 03-28-05 05:30 AM

there this little electric box that of you hook it up to the car it will send current thru it, and prevent rust

Bob Holton 03-28-05 05:48 AM

they tell me that the POR stuf is good.

2wankel 03-28-05 06:40 AM

Por-15 :D

Wankelguy 03-28-05 10:26 AM

Treat rust with phosphoric acid. A couple of brand names are Os-Pho and Rust-Mort.
You can get it at the automotive paint store. The Permatex stuff isn't that great.

mpetersrx7 03-28-05 10:32 AM

I like POR Metal Ready which eats away the rust. Then I treat with POR 15.

Tom 03-28-05 10:39 AM


Originally Posted by 2wankel

I like their blurb on the website

When you buy from us, we consider that a sacred trust and we'll always be there for you. Call at any time with questions or comments. Everything you buy from POR-15 is guaranteed to satisfy, or your money back. We're even interested in knowing what project you're working on.
Anybody call them at 3a.m. with a question?

Dan_s_young 03-28-05 10:53 AM


Originally Posted by RexRyder
there this little electric box that of you hook it up to the car it will send current thru it, and prevent rust

I was thinking of an idea like this before... I know that bridges use a similar system to prevent rust... But I was thinking what would the electrical current do to all the grounds the car has? My guess is it would only cause trouble.

Felgar 03-28-05 10:53 AM

Another vote for POR-15. It's different than anything else out there.

This is the procedure that I employ, and it's worked pretty well. First physically grind down the rust so that you're left with smooth, shiny metal. Even if you end up going right through, just keep in mind that the damage is already done regardless of how much you grind now. There will be the odd small pit of rust left, but that's ok. Then treat with Marine Clean and Metal Ready (both part of the POR-15 "Super Starter" kit)... The Metal Ready kills the rest of the rust and leaves a layer of Zinc which should help for rust prevention. Then apply POR-15 in a few coats.

It's a strange consistency that allows for fairly thick application, and when it dries, it's extremely hard but also flexible. And there's no way that any water is getting through a layer of POR-15 any time soon.

Judging from my other fairly extensive experience with the black-turning Rust Coverters, the POR-15 treatement will last much better. It's also much more durable for keeping repairs free of further damage like rock chips, which negates the other rust treatements pretty quickly. Despite the POR-15 instructions that say you can apply to completely rusty surfaces, I'd say that's pretty much folly, and advise grinding. A rotary tool like a dremmel is a good investment, and really some power tool is the only way that you'll be abe to grind down the rust properly.

Oh, you can also use POR-15 instead of Epoxy for filling any small holes with fiber-glass matt too. It's amazing stuff, really. :)

Edit: After looking at your pic, what I'd do is take an angle grinder with a wire wheel to clean everything, then prep and apply POR-15. It's not like you have layers of rust build-up to worry about. Although I've mainly used it for heavily rusted panel areas like the wheel wells, I think it would work really well for something like your rear end as well.

64mgb 03-28-05 10:56 AM

Sandblasting and a self-etching primer has always worked great for me.

Good luck
Rich

Lee Lyons 03-28-05 11:05 AM

Permatex makes a rust treatment that turns the rust into a paintable alloy...what I did was on the big rusted areas I used a sand blaster then painted the rust treatment on then on the smaller things I just used a wire wheel on an angle grinder then rust treated it again...the stuff that permatex makes works excellent I highly recommend it!

RexRyder 03-29-05 01:41 AM


Originally Posted by Dan_s_young
I was thinking of an idea like this before... I know that bridges use a similar system to prevent rust... But I was thinking what would the electrical current do to all the grounds the car has? My guess is it would only cause trouble.

its nothing new, i seen it in a jc whitney catalog. so i dont think there would be problems

RXTbone 03-29-05 04:31 PM

I'll throw my vote behind Eastwood's Rust Encapsulator. Blast if you can, or at the very least sand well, then coat it with Encapsulator. I've used it on several cars with excellent results...

Here's a link to Eastwood's site - they've posted a comparison test between POR15 and Rust Encapsulator that was published by Auto Restorer magazine.

http://www.eastwoodco.com/jump.jsp?i...88&iSubCat=852

Felgar 03-29-05 05:28 PM

Sounds like a different brand of a very similar product. It is nice that it coexists with solvent cleaners, whereas POR-15 does not. Solvents would have helped in prep for sure.

You probably couldn't go wrong with either, but having used POR-15 I can personally attest that it's top notch.

busterz 03-29-05 06:25 PM

Plasma cutter

DAVID GRIMES 03-29-05 09:01 PM

Elbow grease !

lovintha7 03-29-05 09:08 PM

Get your parts made from K Monel....that shit will NEVER rust.....trust me....if a sub can be in saltwater for 25 years, and nothing's happened to the metal, it's never going to corrode....only problem is that it's expensive as hell, and it sure ain't light.

PT Ray 03-29-05 11:38 PM

It is not that the chemicals remove the rust it is that it turns it into a stable compound known as "black rust". As "WankelGuy" brought up the main chemical is phosphoric acid. Black rust will not continue to eat away at the steel and can be covered with paint, filler or sanded away.

Wankelguy 03-31-05 11:05 AM

Phosphoric acid changes rust from iron oxide to iron phosphate, which is inert.
Phosphating is similar to "parkerizing", the finish used on many military weapons.
Go to a PROFESSIONAL restorer and ask what he (or she!) uses, that's how I learned about phosphoric acid. BTW, a bottle of Os-Pho runs about $7-8 and goes a helluva long ways.
You can even cut it with water. I've never used POR-15, but I've heard people get good results with it. But it costs a lot more, and I suspect that it is just a glorified phosphoric acid preparation.
I HAVE used the so-called "rust-eater" products made by turtle wax and permatex and have found them to be inferior to plain old phosphoric acid.

Hoodsy 03-31-05 12:40 PM

hey folks, I have worked in the marine industry for years and the best way to get rid off rust on steel is with muriatic acid which you can pick up dirt cheap at most hardware stores. if it is a part that you can remove and soak than take some acid and cut about 20:1 with water and leave the part soak over night, it will remove all rust perfectly and leave just good metal, which once you rinse it off will be ready for paint, no sanding or grinding. if it is a part that you cannot soak than pour some of the acid into a container and with a paint brush , brush the acid over the rust, just keep rubbing the area with the brush and acid and watch all the rust disappear. make sure you wear googles and gloves and a face mask, the fumes can get pretty bad. be sure to rinse the area with lots of water after each application of the acid , and when done cleaning you will want to cover it with paint or primer soon because the metal will be etched and will be open to rust very quickly. phosphoric acid works also but not quite as well, phosphoric acid is the best for cleaning aluminum, when cleaning aluminum just follow the same procedure as with muriatic and steel. and those rust converters that turn rust into primer, most do not garantee against future rust on steel, so it is better to just rid yourself of the rust altogether.at least b y using this method with acid it is cheap and virtually effortless. hope this is some help to you guys.
;)

Kentetsu 03-31-05 04:23 PM

Good info just when I needed it. Just have a couple of small areas of surface rust I need to nip in the bud. Thanks guys. :)

cannonjocky 04-03-05 09:10 AM

I have never seen anything work better than muratic acid. (not sure about the spelling)
and you can get it at any hardware store. just paint it on and stand there and let it go to work just be sure and rinse good and treat it quick when your done. takes only minutes.


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