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Best rust converters for surface rust

272K views 86 replies 23 participants last post by  toolboxchev 
#1 ·
So I've been looking up rust converters and have read mixed reviews on here and elsewhere on most of them. Some people swear by POR15, others say to stay well away from it. My dad used the Rustolem Rust Reformer on his Bus and it appears to work quite well but seems a little too hard - like it might crack. Then there's the Eastwood ones I've heard mostly positive reviews on. Which ones work? What about the spray chemicals that are supposed to remove rust?

I want to do the floorpans and some hard to reach areas of my car then undercoat it. The whole floor is light surface rust. I want to stop it and keep it from turning into rot. Are there any better options? Media blasting?
 
#2 · (Edited)
This is what I've used for years. http://www.hotrodders.com/forum/ospho-solution-rust-removal-175465.html?highlight=the+Ospho+solution
Heres another good one...
http://www.hotrodders.com/forum/sec...ealed-55679.html?highlight=the+Ospho+solution
both are inexpensive (under 20.00) and remove rust but need to be scrubbed in not painted on There many phosphric acid products out there but Ospho is what works best for me. It aint as easy as painting something on but it works a whole lot better.
use an epoxy primer over it...
 
#5 ·
I forgot about the Naval Jelly, that really seems like the best option - at least for areas I can reach. The only thing is I've only seen people posting about using it on fenders, hoods, roofs, etc. Anyone have experience using it on a floorpan standing under the car? Does it drip, run off, etc?
 
#7 ·
John68040 said:
So I've been looking up rust converters and have read mixed reviews....

....The whole floor is light surface rust. I want to stop it and keep it from turning into rot. Are there any better options? Media blasting?

They do convert the rust to "something".

You CAN paint this "something".

But there is a good chance that someday sooner or later that acid will creep through your paint and do nasty things. Why risk it? If you can abrade the metal until it's shinny clean, and cut out the cancer spots/weld in patches,...

An Epoxy will last many more years than any "Rust Converter" could ever dream of.
 
#9 ·
Ospho and Navel jelly have a few advantages over paint on converters,they actually REMOVE rust and convert any small traces left behind to iron oxide.
A few advantages Ospho has over navel jelly is its much stronger ,faster and does not need to be neautralized with water...I've personally never had a paint problem with it in 35 yrs and hundreds of cars.But then again I've seen people screw up using W&G remover so its not fool proof...
My personal opinion is ,if there's rust I wont prime if its not scrubbed down with Ospho first (its the law) even if a car is sandblasted it gets Ospho right away to protect the bare metal from surface rust
You can put it in a pump bottle and spray it on it can also be used as a converter and simply spray it on and paint when its dry...I dont use it this way but The guys that paint rusted metal roofing swear by it.
so if your looking for an ez spray on half measure fix you might as well save a bunch of money too Ospho only costs 15,00 a qt but for the bottom of a floor pan you should use a rubberized undercoating on top.
 
#10 ·
How many people have actually sanded the converted rust spots that now appear black? Can't speak for Ospho, never used it, but other rust converters I've tried, whether it be other naval jelly or even zinc phosphate turn what rust spots that aren't dissolved black. If you go sand those black spots after they've been 'converted,' you hit more orange rust underneath. That just doesn't sit right with me so I mechanically remove all the rust first if it's just surface rust. Then I'll put epoxy over it.

Also, I'm just a hobbyist, not a pro.
 
#12 ·
Rust under the black

Don't get shook up about it, rust can keep rusting with out water and oxegen thats what the black converted acid does it converts it and seals it. if you sand it off you have opened the wound again let it be and drive and be happy. Do not try to cross bridges until you have to cross it. I have never had a problem with the stuff i use shelf life is only good for 7 or 8 months I buy a pint at a time. It says on the directions do not sand or grind after you apply the stuff. Its only a Car fellas.
 
#13 ·
Lizer said:
How many people have actually sanded the converted rust spots that now appear black? Can't speak for Ospho, never used it, but other rust converters I've tried, whether it be other naval jelly or even zinc phosphate turn what rust spots that aren't dissolved black. If you go sand those black spots after they've been 'converted,' you hit more orange rust underneath. That just doesn't sit right with me so I mechanically remove all the rust first if it's just surface rust. Then I'll put epoxy over it.

Also, I'm just a hobbyist, not a pro.
EXACTLY!!!!!!! give that man a cigar.....
strip off the paint ,sand with 80,get out the wire wheels and ospho and get that rust out of there...do it again if you need too...then start prepping for epoxy....it IS a lot of work and it dirty... but sometimes media blasting just isnt a feasible way to go
 
#14 · (Edited)
John68040 said:
That's what I want to do. Remove rust, primer+epoxy, then undercoating over that. Can either Ospho or naval jelly be used easily enough while the car is on a lift and I'm standing under it?
Sure, its like the other member said its only a car and how much time and money you want to spend on a repair is totally up to you. To start with you have to remove all the undercoating and find ALL the rust or you can,OR you can just hit the spots you see with a wire wheel and convert them.It all depends on how nice you want it ,how long you want it to last and how much time your willing to put into it...
Hey,theres even a guy in town that painted the bottom of his floor to look like diamond plate,it was impressive but not very practical or cheap...
 
#15 ·
there is no such thing as "converting " rust. you can use various chemicals to turn it black or purple even pink but it is still rust living in the metal . you can cover it up with any of the wonder snake oils but it is just covered. sooner or later all that will be left is the snake oil because the metal will still rust. one pin hole all the way through and you have a snug warm rust hotel .
if it was that wonderful you would see high end restoration shops swearing about it instead of swearing at it . your car, your choice .
 
#16 ·
deadbodyman said:
Sure, its like the other member said its only a car and how much time and money you want to spend on a repair is totally up to you. To start with you have to remove all the undercoating and find ALL the rust or you can,OR you can just hit the spots you see with a wire wheel and convert them.It all depends on how nice you want it ,how long you want it to last and how much time your willing to put into it...
Hey,theres even a guy in town that painted the bottom of his floor to look like diamond plate,it was impressive but not very practical or cheap...
I really want to just remove it all. I figured rust converters were too good to be true.

It may be just a Pinto, but I want to keep the car on the road for a long time. What should I do in the areas where I can't get Ospho/naval jelly or a wire wheel? Like in seams, the 'frame' rails, etc?
 
#17 ·
Ospho is a liquid if you put it in a pump bottle and turn the nozel to a stream you shold be able to get it just about anywhere...if you cant reach it theres not much you can do except douse it good and let it dry ,mabee use an air blower to blow it even further.at the factory they dip the body in a big tank...You got a swimming pool???? ......I'm kidding..
 
#19 ·
50bowTie said:
They do convert the rust to "something".

You CAN paint this "something".

But there is a good chance that someday sooner or later that acid will creep through your paint and do nasty things. Why risk it? If you can abrade the metal until it's shinny clean, and cut out the cancer spots/weld in patches,...

An Epoxy will last many more years than any "Rust Converter" could ever dream of.
The "something" is iron phosphate. Rust is "iron oxide"... an ongoing process. I imagine all of these products (like Phospho) contain phosphoric acid... which converts the iron oxide to iron phosphate. It is dead, and just lays there forever. The acid is not a problem if you can follow the directions on the can. Another trick is to wipe it with degreaser to help neutralize any residual acid.

I will add that right now I am completely redoing an AMX, which was stripped to bare metal and then epoxied. It had been a number of years, and when I sanded through the top coats, and into the primer, I found little buds of rust growing every where. Further investigation show that it was rust under all of the bodywork too!

We took it all off, and started over. A simple treatment with the antique "metalprep" (which contains phosphoric acid) would have saved the guy at least $5000. I have used it for about 40 years (hundreds of paint jobs) without a single failure. You will hear lots of new ideas and technology... but I like simple, inexpensive solutions that work.

I would recommend any phosphoric acid product that performs this simple conversion process. It has been proven for longer than most of the painters on here have been painting.

Just remember... rust starts on a microscopic level, which you can't see. Play it safe, and add some cheap insurance.
 
#20 ·
TucsonJay said:
The "something" is iron phosphate. Rust is "iron oxide"... an ongoing process. I imagine all of these products (like Phospho) contain phosphoric acid... which converts the iron oxide to iron phosphate. It is dead, and just lays there forever. The acid is not a problem if you can follow the directions on the can. Another trick is to wipe it with degreaser to help neutralize any residual acid.

I will add that right now I am completely redoing an AMX, which was stripped to bare metal and then epoxied. It had been a number of years, and when I sanded through the top coats, and into the primer, I found little buds of rust growing every where. Further investigation show that it was rust under all of the bodywork too!

We took it all off, and started over. A simple treatment with the antique "metalprep" (which contains phosphoric acid) would have saved the guy at least $5000. I have used it for about 40 years now without a single failure. You will hear lots of new ideas and technology... but I like simple, inexpensive solutions that work.

I would recommend any phosphoric acid product that performs this simple conversion process. It has been proven for longer than most of the painters on here have been painting.

Just remember... rust starts on a microscopic level, which you can't see. Play it safe, and add some cheap insurance.
So would you recommend stripping to bare metal, treating with phosphoric acid, then using epoxy?
 
#23 ·
wax and grease remover will not neutralize acid. only water will do it. pull any tech manual and check if you like. ppg, dupont doesn't matter . they all stress to neutralize their metal prep with water.
 
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