Rust! Anybody do DIY undercoating?
 

Any tips besides moving to a state that doesn't use salt during long winters?

Here's the deal. I live in Michigan and we have long winters. They use a LOT of salt on the roads. My 2004 Mazda has some small patches of rust that I noticed when I was trying to take off my hitch. It's right there on the frame. I should have taken pictures. In fact, I'll probably take pictures of the other places once I get the stupid hitch off.

I got a grinder attachment for my drill and worked it off, then sprayed it with primer. That's the only thing I had.

Does anybody have any experience with undercoating?

m

undercoatign may or may not work. it will block water from touching the metal but in turn will keep water behind it if it does get back there somehow.

they have undercoating in a can. just follow its direactions and might be fine.

I think if there is already rust on the frame, after trying to get most of it of with that grinder attachment, I'd first try and stabalize whatever rust may be left with some of that industrial paint you can use over rust, before putting the underbody coating from the can on it. That way you will not close up a space with still some small pecks of rust underneath taht might still try and spread out again.

Way back when I helped a friend "restore" a couple Chevelle's and Camaro's -we used a product called POR-15 on the frames/underbodies . Seemed to hold up to Minnesota salt pretty well . Still available I believe ( ? Eastwood ? seems to ring a bell )

Its good stuff and I have used it on the rusty spots on my Civic. Their website is www.por15.com.

Rust proofing seals the car, no good.

Gotta keep the rust out. Oily metal cannot rust. Fill door bottoms, rockers, frames, etc and spray underneath with a mix of chain bar oil and motor oil, or even use grease in some cases.

A friend has done this for years with Peugeot 504s in North Ohio/Cleveland, and they never rust!

I've talked to people who sware by linseed oil sprayed to the bottem of new-ish cars, as it stays soft and flexable, I've used an undercoating that only skims over, insted of hardening right away, the idea being that it is self repairing if it gets scrached, but most of the problems I've seen with undercoatings comes when they age, and harden.
I have some rust of my civic that I first sprayed with rust reformer, that stuff that turns rust black, the clame being that it is then paintable, the problem is however that it is water saluable, so you need a solid paint over it, the stuff I have over rust is then covered with clear boat building epoxy, and is visable, it has not yet started to rust again, so it seems to have worked stoped the rust.
so to repair rust my opinion is that a rust nutralizer, or reformer, fallowed by a paint, or if it needs to be filled, an epoxy filler, then paint, and a solid quality clear coat, and if it's in a fender or underbody area a solid rubber spray on undercoating.

Come on, let's go all the way.... cosmoline!

Also, I found that moving my cars from MN to CA did wonders for my rust problems :-)

It seems like I'm always fighting a losing battle with rust too:mad: . Even my 2000 gmc is getting rusty rocker panels :( . Does it work well on it's own or did you use the marine-clean and metal-ready along with it?

I was looking at something similar to the POR-15, but being a broke-*** college student, settled for something like this:
https://autozone.com/selectedZip,4680.../selectZip.htm
I know folks who have used it....they told me that you just wire-brush off the big flakes of rust, then paint this stuff on. Use 2-3 coats, then use real paint over the top. I've seen the cars that it's been done to.....One is a beauty of a Fiat, and the frame/body that was painted with this has held up very well to several Indiana/Michigan winters.

Personally, I'm going to use this on the bottom of the doors/rockers/quarter panels on Julie, then paint over it with Herculiner. (spray/roll on bed liner) That stuff works like a charm......


On the other hand, I've got an uncle who swears by the used motor oil routine. I've done it, it works. Just drill a small hole in the inside of your door/quarter/whatever, and using a old-school oil can, fill that door panel up until the oil starts to run out the bottom seal. Then run up and down a dusty gravel road a few times, to cover all the oil with dust. This worked well on his 84 Bronco....When he sold it 5 years ago, it was still in showroom condition, after surviving 250K+ miles and 15 years worth of Northern OH winters