TheSamba.com :: View topic - epoxy primer over rustoleum rust reformer

Sun Jan 30, 2022 5:42 am

I thought this rustoleum rust reformer was gonna be just what i needed as my first coat over bare metal and filler areas. I guess I figured that it would act as a first layer of primer as well as treating any small missed pockets of rust (the kind that can only be got by blasting). probably should have done some reading before I prayed half the bus with it.

now i read that when I spray an epoxy primer, the solvents in the rust reformer will come out, and lift it under the epoxy. Please say it isnt so! Ive got 3 cases of this shit on the shelf that i dare not use now.

there seems to be some mixed use reports of some guys having no problem shooting over this stuff, but more of the reports are just the opposite. i am a novice at bodywork, and this isnt designed to be a show car or anything, but do want to have a respectable finish on it in the end.

i was planning on putting a high build primer over that next to help fill any tiny spots i missed with the filler and help with any rough paper scratches before topcoat. is there any way to seal this stuff before epoxy? can i change course on the next layer of primer and use something other than epoxy? my topcoat is single stage Omni.

i just finished the slider and was thinking of experimenting with it now vs. shooting the entire bus. if i do shoot the epoxy over the reformer, how long before i would expect to see lifting? days, weeks, etc. ive got plenty of time, so if it could take weeks, I could experiment now.

Sun Jan 30, 2022 8:19 am

I haven’t used the Rustoleum rust reformer I used the Eastwood version of this. Top coating wasn’t a problem. What does it say on the can? After it is cured I would scuff it with a scotch brite pad and spray the epoxy on it. Maybe start with a small area and see how it goes.

Sun Jan 30, 2022 9:25 am

Epoxy will usually stick to anything.

Sun Jan 30, 2022 9:29 am

if you have a problem, I think it's going to be within a day or so.
Better than the rust "reformer" would be OSPHO and then epoxy. Ospho is Phosphoric acid, which neutralizes the rust chemical reaction, and it's also an ingredient in. the rustoleum reformer paint.
There are a few videos on YT showing epoxy over ospho, it works well when prep is done correctly. Epoxy really wants bare metal with some tooth to grab, so bear that in mind. Maybe just use the reformer where there are blind pockets that are difficult to treat and get it to bare metal everywhere also?
FWIW, I recommend the SPI epoxy. I just sprayed my 52 zwitter project and am very happy with it's adhesion and how sandable it is.

Sun Jan 30, 2022 2:54 pm

the can doesn't say shit except to topcoat with “rustoleum…”. i have a gallon of phosphoric acid and have used that several times before. nothing on the rustoleum can mentions that is in it. the only thing listed is butane (propellent), benzonite, and some other stuff.

since I dont plan on a finish coat for months, just gonna test on this one panel and see what happens. i have already sanded but am gonna scuff up when ready.

Sun Jan 30, 2022 7:02 pm

What's the exact name of the Rustoleum product. I just checked a couple of MSDS and they appear to have different formulae.

Neither of the ones I found had any phosphoric acid in them.

The one I did find that was an aerosol had a lot of different and aggressive solvents in them.

Frankly I'd just stick to cleaning and using Ospho/phosphoric acid.

Mon Jan 31, 2022 4:32 am

viiking wrote: What's the exact name of the Rustoleum product. I just checked a couple of MSDS and they appear to have different formulae.

Neither of the ones I found had any phosphoric acid in them.

The one I did find that was an aerosol had a lot of different and aggressive solvents in them.

Frankly I'd just stick to cleaning and using Ospho/phosphoric acid.

its rustoleum rust reformer #215215. its a general purpose aerosol here in the states. not formulated for cars specifically, so thats my first mistake.

heres part of that msds. Im not stuck on using this stuff, just trying to determine if i need to strip back the 1/2 that already has this on it. Ive been doing sections at a time, working my way around it.

its just rattle can to keep surfaces protected while i continue to work. still think im gonna pick up some epoxy primer and test on the slider. for now, as i go around to the other areas that need work, i will just hit it lightly to cover the bare metal. its indoors, so very little flash rust concerns.

wow! half of whats in here is of “unknown toxicity”? WTF!! sounds like a clever way to avoid being sued for causing cancer in its users.

Mon Jan 31, 2022 4:37 am

esde wrote: if you have a problem, I think it's going to be within a day or so.
Better than the rust "reformer" would be OSPHO and then epoxy. Ospho is Phosphoric acid, which neutralizes the rust chemical reaction, and it's also an ingredient in. the rustoleum reformer paint.
There are a few videos on YT showing epoxy over ospho, it works well when prep is done correctly. Epoxy really wants bare metal with some tooth to grab, so bear that in mind. Maybe just use the reformer where there are blind pockets that are difficult to treat and get it to bare metal everywhere also?
FWIW, I recommend the SPI epoxy. I just sprayed my 52 zwitter project and am very happy with it's adhesion and how sandable it is.

will look at the SPI, thanks. will have to see if its compatible with PPG, as I already have a couple gallons of omni for the topcaot. Omni makes their own epoxy, MP170.

Mon Jan 31, 2022 8:14 am

Top coating rust or “neutralizing it” is a band aid solution at best. The only way to deal with rust is to remove it. The reason why so many paint jobs fail is because people take a shortcut on dealing with surface rust.

Mon Jan 31, 2022 2:06 pm

The MSDS you show is not what I found on the Rustoleum website for #215215 aersol! The one you show is 357402. Which one do you have?

Here's what I found..

https://www.rustoleum.com/MSDS/ENGLISH/215215.pdf

HAZARDOUS SUBSTANCES Chemical Name
Acetone
Propane
n-Butyl Acetate
n-Butane
Hydrous Magnesium Silicate Xylenes (o-, m-, p- Isomers) Dimethyl Carbonate Hydrotreated Light Distillate
Ethylbenzene
Carbon Black
Naphtha (Petroleum), Heavy Aromatic
Zinc Phosphate
Sulfonic Acids, petroleum, calcium salts, overbased Zinc Oxide
Methyl Ethyl Ketoxime

Mostly solvents and some minor zinc products. Generally reasonably safe.

Mon Jan 31, 2022 5:01 pm

you are correct. i linked in the wrong page. it is indeed 215215 per the bottom of the can. alot more shit in that one then the one i listed. thanks

Mon Jan 31, 2022 5:34 pm

Jetfxr69 wrote:
will look at the SPI, thanks. will have to see if its compatible with PPG, as I already have a couple gallons of omni for the topcaot. Omni makes their own epoxy, MP170.

My personal experience is that Omni 2k primer and single stage over the SPI was no problem. Check the forums at SPI or call them. I like it as it sprays with a 1.3-1.4 tip like paint. The cheap epoxies need a 1.8 tip and spray like mayonnaise, and then they never sand well. I'll never go back

I may have been wrong about the neutralizing phosphoric acid in the rust reformer paint, but I definitely;y read it about one of the common "converter" paints.

And like Braukuche states, it's no shortcut. I remove everything I can, and use Ospho afterwards, to hopefully kill any rust that I missed.

Tue Feb 01, 2022 3:07 pm

my 0.02?

pick a system and stick with it. this is why i like to sand blast first and then epoxy.

my experience has been that anything incompatible will lift at some point. could be right away, could be a year.

very few rust elixir's play well with "real" topcoats. they may be ok with a rattle can but the solvents in "real" topcoats destroy many encapsulation products.

you have to remember, a lot of body work relies on chemical reaction to bond one coat to the next.

Sat Feb 05, 2022 3:16 pm

The problem here is that both of these Rustoleum products are PAINTS...not just pure "rust converters" or "rust killers".

#215215...this one is a straight up classic paint.

# 357402.....this one...is an acrylic top coating.

The problem people are getting into with what ACTUALLY in these products and others....are the fact that there are no longer "MSDS" being made anywhere for any product. :wink:

The name has officially been "SDS" since June 1, 2015.

Along with the change from "Material Safety Data sheet" to "Safety Data Sheet"...as part of the world wide change over to the "GHS" system in 2012.............the requirements of WHAT manufacturers were required to list in the "SDS"....changed.

They are no longer required to list ANY ingredients at all.........unless they are HAZARDOUS or CONTROLLED or REACTIVE!

So.....that means that you do not actually SEE some of the most important ingredients listed. It has been a real problem in manufacturing.

Just because something is not a physical hazard to people....or just because its not reactive PH wise or cause KNOWN hazardous polymerization....does not mean that it may not create or cause a change in other ingredients in a process.

And...even if an ingredient is hazardous it may be listed only as 'trade secret" if its volume in the mixture ...and normal usage...is below TLV limits.

It sucks!

I would have used phosphoric acid, then wipe down with acetone and then primer immediately. Thats all you need.

Personally I like the "Master series silver- permanentrust killer". AWESOME chemistry.
Ray

Sat Feb 05, 2022 9:19 pm

I didn’t want to get pedantic with my answer re SDS as the file names were actually MSDS suffixes.

I managed the GHS SDS system for a large manufacturing company with 4000 separate raw materials and understand the requirements.

Suffice to say, the layperson can actually glean a lot of information just from the Hazardous component listing of most products.

And of course if you looked up the SDS for ethanol you’d never have another drink again!

Fri Feb 11, 2022 12:16 pm

Up to this point I have only used Masterseries Silver along with Duplicolor "rust fix". I used up my last can of rust fix and went and bought another, along with a can of Rust reformer, and Rust Barrier. I usually do not use this stuff on outer panels, I usually use this rust stuff underneath where people don't look. I did Masterseries the entire car, and then high build over that.
I figured I could experiment on my Jetta with these other products and see what happens. Replacing all the brake hard lines from the master cylinder all the way to the rear axle, the salt and chemicals are eating everything up. Its definitely a good test bed for rust products.

Thu Feb 24, 2022 8:58 am

esde wrote: if you have a problem, I think it's going to be within a day or so.
Better than the rust "reformer" would be OSPHO and then epoxy. Ospho is Phosphoric acid, which neutralizes the rust chemical reaction, and it's also an ingredient in. the rustoleum reformer paint.
There are a few videos on YT showing epoxy over ospho, it works well when prep is done correctly. Epoxy really wants bare metal with some tooth to grab, so bear that in mind. Maybe just use the reformer where there are blind pockets that are difficult to treat and get it to bare metal everywhere also?
FWIW, I recommend the SPI epoxy. I just sprayed my 52 zwitter project and am very happy with it's adhesion and how sandable it is.

Actually I found after buy a few cans that the "rustoleum rust reformer" is a total joke. It has NO phosphoric acid in it despite what you might assume or are led to believe. I don't think it has any sort of rust "converting" chemicals in it... it's simply flat black paint from everything I can tell. Writing/warnings on can, smell, etc... it's just cheap flat black spray paint. Such a rip off and misadvertising. I'm surprised it even has decent reviews... Just goes to show you most people don't know there own hole from a hole in the ground. :roll:

I reccomend SPI epoxy as well.

Many times acids and epoxy don't play together, won't cure right, etc. You need to read up on that.

Thu Feb 24, 2022 11:48 am

Wikipedia;
Tannic acid chemically converts the reddish iron oxides into bluish-black ferric tannate, a more stable material.
I think that the use of acid is best for last stage after physical rust removal that a tool can't get. In my opinion, Rust Reformer is good for trying to slow down rust spots on a car that is not going to get attention soon. :)

Wed Sep 10, 2025 10:10 am

Hi OP - I jumped in to the same boat, and I'm curious how your project turned out? I used the liquid/brush on rustoleum converter as opposed to the aerosol- but I'm having the same doubts as to whether or not I screwed up. I like your approach of doing a test panel. In my situation too, I feel like at least the stuff I put on there is buying me some time, but I sure wish I'd have done a little more reading before I applied it. I think I'm gonna work on sanding mine off though, I don't think it will be too hard since I used it on body panels --> easy access. Anyway...I hope you have had success in your project!

Wed Sep 10, 2025 7:17 pm

Just an observation here.

22 years ago I bought a 1973 Mustang. The inside floor of the trunk was rusty.

I sanded off all the loose rust and applied some POR-15 over the still attached, fairly smooth rust surface. I never finished up with a repaint.

When I sold the car 3 years ago, 19 years later, the trunk was in the same condition as when I applied the POR-15 19 years prior. When I pulled the gas tank a couple of years before I sold it, there was no evidence of any upcoming rust-through on the bottom of the trunk floor.

I am convinced that if a POR-15ed surface is sanded smooth with a proper grit (280-320) for epoxy, or self etching, primer adhesion, the then painted surface would last just about forever, iow, no rust-through.

Unless someone has a definitive reason why this wouldn't work, I am going to try this on a rust bubble on my Civic's front fender.