Underbody rust/undercoating/rust prevention

[Kyle_T]

So I'd like to take car of the rust on my underbody before the car is on the road. As it looks now, the car will be driven in the winter. Id like to "rustproof" it as much as possible.

The car came from the south and was driven in 1 wisconsin winter by previous owner. The under body seems fairly clean, but there is still quite a but of rust that id like to be gone. And Id like to prevent anymore rust from forming. I read that to do a proper undecoating job all rust and moisture has to be completely gone otherwise the rubberized undercoating will trap the moisture and it will rust the underbody even faster.

Heres some picture I took of the underbody today.

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Worst 2 spots:

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My plan was to:
1. Grind off all major rust spots, and get rid of all "loose" rust
2. Brush on rust converter on all the rust that is left.
3. Clean/Prep rest of underbody
4. Spray rubberized undercoating.

So let me know what you guys think. Any input is great.

 

[Kyle_T]

Then whats the point of the por-15 if you have to put something over it? Most of my underbody is rust free, but has the oem undercoating on it.

And i tried removing some of it and its a pita. Haha

 

[Guzman08]

so how much are u going to spend in all

 

[Kyle_T]

I decided to go in a little different way. Im still grinding down all the rust i can, and using the rust converter. But instead of a rubberized undercoating over that or por15 Im painting pretty much everything in rustoleum. Im doing a couple thick coats and it seems to be going on nicely. I started to remove some of the factory undercoating and realized that the metal is perfectly fine underneath it, so why remove it?

So basically in going to paint everything possible with the rustoleum because its alot cheaper. And im still debating, but i might spray some undecoating over it. Ill post some pics when I make some more progress.

 

[extremeatheist]

por-15 ftw!

 

[Kyle_T]

I was really considering por-15. I probably wouldve used it if the rust was absolutely horrible or it was a really clean car. But I figured the rustoleum will be fine. I think the car got so rusty because it sat in someones garage for over 6 years. I will wash the car alot during the winter so it hopefully wont be a problem.

Ive been using Rustoleum "stops rust" in semi-gloss black most alot of stuff. Im having trouble finding a rust preventing paint that is close to the factory a52 silver color. I know it will be under the car so it doesnt have to be exact, but id like something close. I tried rustoleum stops rust in aluminum color and it was pretty dark compared to the facotry color. And one got any other rust paints I could try?

Also does anyone know if its safe to use a rust converter on a headshield? The headshield by the cat was super rust and i grinded the crap out of it, but there still a good amount of rust. Im going to paint it with heat paint, but can I use the rust converter on it first? Or does the headshield get too hot?

 

[pj91gsx]

I was really considering por-15. I probably wouldve used it if the rust was absolutely horrible or it was a really clean car. But I figured the rustoleum will be fine. I think the car got so rusty because it sat in someones garage for over 6 years. I will wash the car alot during the winter so it hopefully wont be a problem.

Ive been using Rustoleum "stops rust" in semi-gloss black most alot of stuff. Im having trouble finding a rust preventing paint that is close to the factory a52 silver color. I know it will be under the car so it doesnt have to be exact, but id like something close. I tried rustoleum stops rust in aluminum color and it was pretty dark compared to the facotry color. And one got any other rust paints I could try?

Also does anyone know if its safe to use a rust converter on a headshield? The headshield by the cat was super rust and i grinded the crap out of it, but there still a good amount of rust. Im going to paint it with heat paint, but can I use the rust converter on it first? Or does the headshield get too hot?

rust conveter does not work well on hot surfaces. your best bet is to paint it with the heat proof primer then heat proof paint. i tried rust converter on my oil pan its peeling and bubbling.

 

[Kyle_T]

Yea, I had a feeling the rust converter wouldnt work on stuff that gets hot.

 

[Kyle_T]

What about using the rust converter on the rear diff? I mean does it get that hot or no? Heres what it says on the website about the rust converter "Can be used when temperature is between 50°F and 90°F (10°C and 32°C) and on surfaces which do not exceed 200°F (93°C)."

 

[Kyle_T]

Little update:

Almost all done with wire wheeling and applying the rust converter. Im going to try and finish up tomorrow and hopefully finish painting this weekend. Ill get some pics tomorrow.

 

[dented_coffee]

Rust reformer dont work at all. it still has rust and eats from the back side of the metal still. I have proof from first hand experiance.

1. wire wheel it all off.
2. clean it up to remove the wax and grease.
3. spray it with self etching primer.
4. get some hurculiner roll on bed liner and put that on it.

My moms old baretta gt had the hurculiner rolled on the underside and it never peeled or cracked. never did rust out or rust at all. and very easy to clean off.

 

[Lofty]

I use a Mig welder to fix my rust, but that's just me!

 

[Kyle_T]

Rust reformer dont work at all. it still has rust and eats from the back side of the metal still. I have proof from first hand experiance.

1. wire wheel it all off.
2. clean it up to remove the wax and grease.
3. spray it with self etching primer.
4. get some hurculiner roll on bed liner and put that on it.

I am pretty much wire wheeling it completly off. its mostly just alot of surface rust that im getting rid of. Im using permatex rust treatment, its a brush on not the spray crap. Ive read reviews and everyone seems very satisfied on the internet.

And lofty, If my rust was a lot worse Id probably get some spots welded, but like i said its mostly just a lot of surface rust.

 

[Coreyred95]

After all that work, I strongly recommend getting a winter beater my friend, I am from the north too and I know what winters are like up here, its hell on a car. I'd recommend getting a cheap 4x4 pickup like an s10 or something. I got a 92 Nissan to save my baby form that salty hell.

 

[Kyle_T]

True, but there is a part of me that wants to drive it in the winter. I mean thats one of the reasons why I wanted awd. I think it would be a blast in the snow. And hopefully by doing this it will somewhat prevent more rust from forming, and granted im going to try and wash the car and underneath at least once a week in the winter.

 

[dented_coffee]

get a cheap awd dsm. dont mod it unless you want to as your winter car. still awd and still able to perform. use it as a test car in a way for products. get a company to help out on product testing like rust prevention. i found some zink plates that are like 6"x3" im gonna mount one by each common rust spont on my next car. it works for boats and stel barriers in the ocean so y wont it work for a small bit of water and salt on the road.

 

[Kyle_T]

A little sneak peak. This is with 2 coats of rust converter. I still have to put a couple of coats of paint over it. Im going back out to finish applying all the rust converter and then I will hopefully have it painted this week.

Before:

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Now (2 coats of rust converter, still needs coats of paint over it)

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Ill get some more pics up later tonight.

 

[Kyle_T]

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Still not totally finished painting, and then going to give everything one last good coat.

 

[JCabral]

about how long did it take you do the hole under body ? and with how many hours a day + days a week?

 

[Kyle_T]

I probably spent a good week just wire-wheeling and grinding off rust. Working on it atleast an hour or two almost everyday. I would advise you do that part outside though, because the dust from the rust gets on EVERYTHING. And then I probably spend about 2 weeks applying rust converter and painting. I didnt work on it everyday though. If you wanted, you could probably get the painting done in about a day if you spend a couple hours on it, but I found that lying under a car brushing on paint was not very fun for multiple hours. So i would just do a small section, and come back a different day. I did about 2 coats of rust converter and 2-3 coats of paint. All brush on, no spray(except for the rear diff cover).

 

[pj91gsx]

that looks really good kyle.. Props

 

[pboglio]

Looks really good. I'm having a tough time stripping rust with the wire wheel, just seems to polish the rust. I like flapper sanding wheels for something like rust removal, wire wheel just for paint removal.

 

[Kyle_T]

that looks really good kyle.. Props

thanks man!

Looks really good. I'm having a tough time stripping rust with the wire wheel, just seems to polish the rust. I like flapper sanding wheels for something like rust removal, wire wheel just for paint removal.

thanks. yea the wire wheel usually will just get rid of the loose rust and the sanding wheel will get down to the bare metal.

 

[Blurred Talon]

Looks awesome man!

I hope to do this with my car soon.

 

[pj91gsx]

Looks really good. I'm having a tough time stripping rust with the wire wheel, just seems to polish the rust. I like flapper sanding wheels for something like rust removal, wire wheel just for paint removal.

if you get all the loose rust off, it gets to the point where you can apply rust converter, which does an awesome job of neutralizing the rust. I used it before, about 5 years ago and it never came back. i used the rust remover, brush on stuff then the rust converter, i didnt even wire brush, this was to a steel bumper support on a 1g eclipse.

 

[CountryDSM]

Hey Kyle, I am bringing this back because I wanted to clarify what products you used and how they are holding up. After everything was wire brushed, what type of brush on rust converter did you use? Also was it just a brush on black paint or was this another type of rust paint? I am about to be going through this whole process.