Rust Converters?

kcav8or

kcav8or

Member
I have my dad's old 1931 Model A. The body is in generally good shape, but the undercarriage has a lot of rust. I don't have time to pull off the body and completely strip it down to the metal, so I wondered about peoples' experience with rust converters. I know it wouldn't be as good as pulling off the body, but I thought it might be a good stopgap.
 

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First off they are not really rust converters like you would hope.

I think stuff that covers over and bonds to rust might be a better name. You will slow down the rust, but the rust still holds oxygen close to the metal surface and will still allow rust to continue. Worse is paint holds moisture in or out. So if you get an edge that lets water between the coating and the metal you will have the rust get much worse. Nothing like the metal going away and you do not even know it. I have experimented with the POR paint and found it looks great and adheres to rust. Rust does not adhere well to the metal so you can get the POR coating to peel off. You will find the rust well bonded to the back side of the POR paint. Personally I like POR paint for coating the inside of metal seams of clean metal. It is thin and flows in the tight areas. You are not likely to get something that will cause the POR coating to peel off either.

The acids will NOT get rid of enough rust buy just putting it on the surface. In fact it will not get rid of the rust at the bottoms of the pits. I did an experiment with a rusty part. I blasted away the rust but allowed the brown spots at the bottom of the pits to remain. I then treated the metal with PickelX which is salt spray rated metal treatment. I have parts that are years old with no rust. Within months there were webs of rust coming out from the rust pits.

So what am I telling you. Be careful as coating the metal may make it look nice and make the rust worse. You are better off leaving the rust to the open air then to put a coating like POR on it.

Other paints like rustolum may be a better choice. Go direct to brushed off metal, not acids. They are not a shell like the POR paints and are way easier to get off it you plan on restoring the car. They go on easy and are much easier to get off your skin if you are painting upside down. You can also tell if your rust is getting worse. It will slow down the rust a lot. In a dry garage you will preserve the car for decades no problem.
 
I would leave the frame as is, or spray it with a light oil, such as ATF, and then never drive it on salty roads and try to keep out of the rain as much as possible. This works for me until I have the time and space to do a correct body off the frame restoration.
 
coat it with used motor oil. it is black and when it dries it looks good, it is what I use on the tractors
 
When I discussed protecting the bottom and top side of my T and A with one of the engineers at work told he me about a study done by the military that determined WD 40 was best at protecting metal surfaces. It was even better than cosmoline (sp?).

I have been using Marvel Mystery oil because it will soak into the rust but am considering WD 40

When I have time I will see if I can find the study
 
I've tried rust converters like ospho and others, after a few years or quicker ,blisters appear and the area must be took back to base metal and redone. POR 15 is a pain to use correctly but has worked good for me, fifteen years with NO signs of failure on my 31 tudor. POR 15 works on clean solid rust if all loose rust is removed. Rusty surfaces should never be cleaned with solvents before appling POR 15 or failure is eminent. Marine clean is the product of choice before appling POR 15. Rust from the base metal will often come right through the original paint and will appear to just be solid rust, POR 15 will fail if this is the case. POR 15 needs to be applied to the base metal, solid rust is no problem, not rust that is on top of paint. One drop of sweat will contaminate POR 15 and can cause failure. I've had good luck with Rustoleum products and it is more forgiving.
 
Here in Maine the liquid salt solution that they are using on the road will rust out new metal in 3 years. The problem solver of choice is Fluid Film. Most people give their under carriage a spray coat every year and it pretty much stops the rust. It comes in a liquid and a gel at $47 a gal. You can spray it on with a gun that looks like the old undercoater gun. The marine supply stores were the first to carry it, now the auto stores are also. A pressure washer will take it off, but other than that it stays on in a semi-soft state.
 
I have tried many different products over the years with mixed results. What I use now is Rustolem rust restorer its a spray that seems to work fairly on most rust surfaces; the heavy scaly rust needs to be cleaned off then spray on the rust restorer and top coat if desired
 
In the electronic assembly industry we use a nitrogen atmosphere to stop oxidation during the solder reflow step

You could put the vehicle in a nitrogen filled garage :D

One of the silicon wafer bump processes uses hydrogen atmosphere and high temperature to remove oxidation from surfaces. You could try that approach but the wood may not like it. :mad:

( one time I mistakenly put a 12 inch wooden ruler thru a belt furnace containing nitrogen at 900 C and it became charcoal. I could still read the numbers but it shrunk about 20%) :eek:
 
JTW said:
Here in Maine the liquid salt solution that they are using on the road will rust out new metal in 3 years. The problem solver of choice is Fluid Film. Most people give their under carriage a spray coat every year and it pretty much stops the rust. It comes in a liquid and a gel at $47 a gal. You can spray it on with a gun that looks like the old undercoater gun. The marine supply stores were the first to carry it, now the auto stores are also. A pressure washer will take it off, but other than that it stays on in a semi-soft state.
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Just to reinforce this, I follow a mini-van (wife's ride) site and it seems half of the members are in Canada, they all swear by this stuff and ATF.
 
"Rust Check" a commercially sprayed product, you can now buy in spray cans for the DIY'er. Its a liquid like ATF in color and consistency, safe on rubber parts and won't harm your driveway. I've had cars in the past sprayed annually, worked great! www.rustcheck.com
 
buddridge said:
No WD40 other than short term use. WD uses water as the vehicle that the propellant moves....not good.
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Are you sure?:confused:

WD-40 is a water displacer and I've used it on wet coils and distributor caps with great success. I also spray it on my underhood bare metal parts to cut down on corrosion.:)
 
nhusa said:
In the electronic assembly industry we use a nitrogen atmosphere to stop oxidation during the solder reflow step

You could put the vehicle in a nitrogen filled garage :D

One of the silicon wafer bump processes uses hydrogen atmosphere and high temperature to remove oxidation from surfaces. You could try that approach but the wood may not like it. :mad:

( one time I mistakenly put a 12 inch wooden ruler thru a belt furnace containing nitrogen at 900 C and it became charcoal. I could still read the numbers but it shrunk about 20%) :eek:
Click to expand...

I tried that once, but somebody mislabeled the O2 bottle for N2, and I blew up the garage! ;-)
 
Aok,
I trired to search for Rustoleum rust remover and couldn't find anything. I did find Rustoleum Rust Converter. Is this what you were referring to?
Rusty Nelson
 
Tom Wesenberg said:
Are you sure?:confused:

WD-40 is a water displacer and I've used it on wet coils and distributor caps with great success. I also spray it on my underhood bare metal parts to cut down on corrosion.:)
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Times 2 ! In fact the distributor guru over on the early V8 side has stated that it is good practice for displacing water as you state ! I'm trying to understand that statement also:confused:
 
Tom Wesenberg said:
Are you sure?:confused:

WD-40 is a water displacer and I've used it on wet coils and distributor caps with great success. I also spray it on my underhood bare metal parts to cut down on corrosion.:)
Click to expand...

I used to believe in WD40, till I moved to the coast. In that salt air environment WD40 seemed to encourage rust. Things sprayed with it rusted much more quickly than things not sprayed at all. This may only be because of the salt air, but even since moving back inland I still am reluctant to use WD40 as a rust preventative.
 
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