Fighting with rust

Joined
Oct 4, 2009
Messages
770
Location
Litchfield, Ohio
I'm currently working on replacing the floor in my 98 Ranger because of rust. Ive sand blasted both the inside and underside of the cab multiple times to try and clean up what good metal is still there. The problem I'm having is the metal is super porous because of the rust and the blasting is not getting deep into the porosity of the metal. So even if I paint it or prime it the rust ends up coming back through. Ive tried multiple rust converters and primers and nothing seems to put a stop to it. Its getting old fast.

Anyone have any solutions? I figure anyone that has blasted super rusty metal has probably experienced the same thing.
 
What rust converters and primers have you tried? I've had great success with Chassis Saver and POR-15 on Jeeps when it is prepped correctly. It's not cheap, but it works.
 
Have you thought of an oil undercoating. I make this homemade grease undercoating and it works fantastic at slowing down or stopping rust. Btw I have a 98 Ford ranger and the entire underside of the vehicle has been coated for 3 years and it's working fantastically.
 
I fear that you at best only can slow it down. If it is that porous the only way is to replace the metal.
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Originally Posted by joegreen
Have you thought of an oil undercoating. I make this homemade grease undercoating and it works fantastic at slowing down or stopping rust. Btw I have a 98 Ford ranger and the entire underside of the vehicle has been coated for 3 years and it's working fantastically.


Can you give us the recipe for your homemade undercoating?

I made a homemade undercoating out of wax from a toilet bowl wax ring*...bar and chain oil (motor oil works too) and mineral spirits. It's a variation of a recipe that I read about on this site. It doesn't spray well because of the wax so I brush it liberally on the underside of the vehicle....seems to work pretty well.

* The toilet ring wax was the type recommended by the original thread (as opposed to candle wax)....I think he called it parafinic wax

PS: If you use POR-15....only buy the amount you can use soon....it does work well but I've never
been able to store leftover amounts without it hardening.
 
I've had great luck with POR-15 in many applications. Just get the surface prep done well. I've been able to save extra by putting Saran Wrap between the can and lid, and then pushing it closed.
 
I agree with joegreen and Donald. Unless you can get a primer/paint system to be 100% coverage, air and moisture will wick in from any crevice, etc. and creep underneath the paint to reactivate the micro rust that you failed to remove.

I , too, have mixed results with rust reformers. I either use one of the "wetter" phosphoric acid based ones or the creamy tannic acid based ones that form a polymer coating. One surprising result I am testing more is the old Rustoleum fish oil based red metal primer ( I don't think the aerosol version is the same???). I've had some remarkable results with the brush on Rustoleum rusty metal primer. Go figure. But again, if moisture and oxygen can creep in under the paint from an unprotected seam, crevice, etc. the rust will return.

A creeping, non (hard) film forming oil that penetrates the "spongy rusted steel" and all crevices seems like the best solution. Apply it several times annually. Trav recommends a commercial product.....can't remember the name.

Put well-type liners inside the cab to eliminate moisture (Weathertech, etc.)
 
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If you can't get enough off (and still have enough metal left) with an angle grinder and flap wheel, it's time to cut it out and weld in new panels. I hate rust.
 
Originally Posted by MarkM66
What sand blaster and sand are you using?

Sandblasting is ideal for rust pores.

+1
 
It is labor intensive and takes ages to dry. Boiled Linseed oil. It forms an airtight seal. No air, no rust growth. I used a 3" brush and gave everything 5 coats when I fish plated the left frame rail on the Rat. I was told by an old jeep guy about using it inside doors and other voids that trap water. I had some so I used it. I prepped with a knotted wire wheel, by no means bright, just descaling. The Rat sits for months at a time and where I've coated hasn't rusted further
 
I used to fight rust on cars. I've given up. It's a lot of work for no reward. The original metal likely had a zinc coating with an underlayment of phosphate coating beneath the paint. All that is gone when metal rusts. Yes, you should remove all rust by sandblasting as I used to do with my cars. Once repainted, the coating will protect for a year, maybe two, unless you retire the car from salt duty.

Undercoating is a tremendous help. If you value your cars, you would have the rustproofing done before the car is put in service. At that point it is a little work for a lot of reward.
 
Originally Posted by jeepman3071
What rust converters and primers have you tried? I've had great success with Chassis Saver and POR-15 on Jeeps when it is prepped correctly. It's not cheap, but it works.


Self etching primer. Was told by local body shop that would do it. Nope

Permatex rust treatment

Ospho

Rustoleum rusty metal primer

Krylon Rust tough primer

Krylon Zinc rich primer
 
Originally Posted by MarkM66
What sand blaster and sand are you using?

Sandblasting is ideal for rust pores.


Using a pressure pot blaster from harbor freight. I'm using fine coal slag blast media from tractor supply.
 
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