Unibody rust, the never ending battle - Page 2 - JeepForum.com
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post #16 of 161 Old 06-26-2016, 08:04 PM
Candymancan
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Quote:
Originally Posted by Timo_90xj View Post
Nope.. none of those stops rust. They just slow it down. Rust needs to be completely removed to stop it. It is as simple as that.

You can try any of those you mentioned, use you vehicle through one or two winters worth of road salt, cold & moisture - and the rust will start to reappear.


well sometimes removing ALLL the rust is impossible. This the frame in the rear on my wagoneer.. I spent like 6 hours cleaning it as best as i could with a grinder, wire wheel.. and a good old hammer to get the scaling chunks off.. Also i cut off the 2 bolts holding that metal bracket in the middle of the C, aparently its a bracket for the once non existing trailer hitch.. and it just rusted the F out of the fram behind it.. And i put 4 coats of rust reformer on it. I also had to cut off like 12 inchs of the lower section of the c channle and the lower part the leaf spring mount and weld in new 1.8th GA steel because you can see how it rusted so badly the c channle was basically gone there. I did it after i painted.. as you can see the bad metal is still there after i painted. I just cut it off later

This wagoneer was in west virginia and virginia all its life.. The other Frame in the rear was almost as bad. I guess I'll find out if the cleaning and rust reformer helped or not. Because short of removing the body off the frame and replacing the frame which i dont have the funds or equipment to lift a 2,000 lbs body off.. This the best i can do. So are you telling me this will come back with a vengengeance ? Or will i have to just clean up some spots thast come back through and repaint ? I dont plan to drive this thing in the rain or snow or salt either.. Its just my sunny day daily driver.. The 5.9 is still rust free not 1 spec.. and its my winter and bad weather driver

I actually got like a shovel full of rust off this section after i sweeped in it a pile lol

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post #17 of 161 Old 06-26-2016, 11:56 PM
Timo_90xj
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If kept in a warm place and driven only in good weather, then you may be saved. If that was driven in wet/ winter/ road salt, all the rust would of course not come back immediately, but in over just one winter you'd be looking at small rust spots forming here and there.

I've had vehicles with way less rust damage, wire-wheeling everything seemingly clean, using rust-reformer and then a few coats of quality paint + lackuer, and even then the rust have come back.



Rust really is like cancer: unless you get even the smallest specks of rust off, it will come back. Wire-wheeling with an angle grinder won't usually remove all the rust, you need sandbalasting or replacing rust with clean steel.

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post #18 of 161 Old 06-27-2016, 01:01 AM
Candymancan
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I guess Ill find out in 3-6 months if it still looks like this or not. I wonder if i coat it with some oil and dirt back there too if itll help.. seems all my vehicles that are coated with oil and dirt are spotless when wiped away LOL. Problem with the wagoneer is the frame is fine otherwise still has factor paint and undercoat on but back here. And i didnt see this due to the spare tire hiding it all when i purchased it.. Then after i removed the tire i saw and i was like hmm.. well damn

I guess the good thing with these trucks is the frame can be swapped if it ever came to it


Ive also heard that coating the frame with a wax and lint seed oil or bar and chain oil for chainsaws keeps air/water and everything away.
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post #19 of 161 Old 06-29-2016, 06:12 PM
ECL
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There are at least 2 mechanisms for the rust to return.
The first is any rust left behind. Painting on top of rust with anything that doesn't chemically react with the rust just means you've just trapped the oxygen molecules at the surface...and it doesn't take a lot of oxygen molecules for the "rusting" oxidation to continue. I think we all know this.
The second is more interesting, at least to me. Paint likes to self level (most liquids do). On a smooth surface, this works great and leaves a uniform film thickness. When the surface is pockmarked from rust, however, lots of little sharp edges are formed. The paint thickness is very thin crossing over these (or is nonexistent) and is usually where the coating "fails" and the rust begins again.
The solution? Grind as smooth as you can, put down a base coat of a reactive paint, then multiple top coats of something thicker to build up over the high points. Brushed paints go on thicker than spray; consider something really thick like tar - just keep an eye on it over time so it doesn't dry out and crack, allowing moisture to get back down to the metal.
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post #20 of 161 Old 06-29-2016, 06:21 PM Thread Starter
Rob K
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One of the main problems with a lot of paints is moisture/oxygen getting through the paint and causing the metal to rust. Obviously paints have gotten much better over the years. Products like POR15 and Chassis Saver are supposed to keep this from happening. Like you say the main problems would be poor adhesion where the paint gets compromised in some way. High spots and corners where the paint is thin. Unpainted surfaces like the inside of panels are a problem. Things rust from the inside out no matter how good your coat of paint is on the outside.
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post #21 of 161 Old 06-29-2016, 06:23 PM Thread Starter
Rob K
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This thread still needs to get moved to the KK forum. I guess it's realavent for XJ's also, but that's a different major project that I'll take on at a later date. I need to get a welder and replace a lot of metal on the XJ.
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post #22 of 161 Old 06-29-2016, 07:13 PM Thread Starter
Rob K
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Removed plastic rocker covers and found plenty of salt and dirt under them even though I wash thoroughly. Are they trying to fix the rusting out rockers by having a plastic cover? I think the problem is made worse since you can't actually see and clean the metal rockers under them. I would love to leave off the plastic rockers and do something different with the fender flares, but there are big voids where these parts are installed. They are not just protective covers, but actual parts of the body that need to be there. Pretty lame. I guess I'll be breaking more plastic mounting clips every time I have to remove the rocker covers to clean. Broke 5 of them. There's no way to pull out the plastic clips without breaking them, because of their design. No way to get a pliers inside the rocker panel and squeeze the clip. Will see if I can get a different style clip. After owning an XJ I find the KK quite annoying the more I learn about it.
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post #23 of 161 Old 06-29-2016, 07:23 PM Thread Starter
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For starters I'm repainting from the stamped frame rails out to the rockers panels on both sides. Next will probably be everything I can get at by removing the the fender flares and plastic wheel wells. After that front and rear end. Lastly the middle of the Jeep where everything is in they way. Motor, transmission, fuel tank, etc. Not sure when or how I will get to all those areas or if I will. Also have to pull the door panels and do the inside bottom. Oh, and all the suspension. This will never end.lol. I should just buy a Wrangler kit and paint it right before assembly.lol Here's a photo from before any prep was done.
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post #24 of 161 Old 06-29-2016, 07:32 PM Thread Starter
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Photo after sanding with 180 grit. Felt wrong to sand perfectly good paint on a low mileage vehicle. I know what will happen if don't take care of the inadequate paint job though.

Started out using an orbital sander, but that just blew through the paint as soon as I touched it. Ended up sanding it all by hand so get in all the crevasses. Even then I had to be careful not to sand through the paint. The undercarriage paint is thin, another bad idea. Also removed a bead of expanding foam on the back of the rocker. Apparently it's supposed to keep crud out of the seam. I found that it trapped moisture and the seam was starting to rust under the foam. It will get a nice coat of protective paint now and seal the seam properly.
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post #25 of 161 Old 06-29-2016, 07:48 PM Thread Starter
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So I was going to put on a few coats of silver Chassis Saver today, but I chickened out based on what I just read on the internet(love it hate it).

Paints like POR15 and Chassis Saver do not bond well to smooth surfaces. Chassis Saver instructions say it's best to sand blast or go over tight rust for best adhesion. A secondary option is to sand bare metal with 60-80 grit. To apply over old paint they say to sand away all traces of gloss with 120-180 grit. This is what I did, but sanded through in some spots and couldn't get the gloss off in all the crevasses. Not sure that I'm going to get good enough adhesion. I need to be able to pressure wash the road salt off pretty regularly.

I sent Magnet Paints and email to see if I would be better off applying a rough coat of primer first. I want to make sure I get it right the first time. I don't want to sand until my fingers bleed again.lol They also say a wire wheel is a bad idea since it leaves the metal too smooth for proper adhesion.

I need to get this painted by the weekend so hopefully I hear back soon and can get primer locally if I need to go that route. Hopefully primers come in different textures.
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post #26 of 161 Old 06-30-2016, 10:01 AM
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I would clean the salt and other grime off, then drench the entire thing in Fluid Film, I would also make sure to get -inside- the rocker panels (even adding a few holes if necessary) and then put the plastic covers back on.

Then repeat every year or so. Although because that area is so protected from direct contact with road particles, the fluid film will stay in place for a very long time.

If it is covered with Fluid Film, it is not going to rust easily at all, -and- if it should start to rust anywhere you will -see- it right away. That is the problem with paints and undercoatings - is that when rust happens under them (and it will) you won't know about it until it is truly awful and coming up through the paint or undercoating).

Por15, Chassis Saver, and Fluid Film all work on the same concept. Keep moisture and oxygen away from the metal. And they can all be successful if the application is correct.

But paints and undercoatings can't creep deep into pinch seams, around corners, and heal themselves in places where they were scratched or rubbed (or missed entirely). They also make the metal invisible to inspection. So especially on anything "internal" or hidden by an external plastic panel, my preference would be Fluid Film.

I'm not saying its magic (though I have been using it in high-salt high-moisture environment on my XJ and it has been as effective as the manufacturer claims). I'm just saying that it matches your application well, is reasonable in terms of cost, and will give you the most amount of flexibility and ability to inspect over time.

Things I keep around that help fix Jeeps:
AeroKroil and Fluid Film
BAFX Products 34t5 Bluetooth OBDII Scan Tool and Torque Pro OBD2 App for Android
Etekcity MSR-P600 Digital Multimeter
Bernzomatic TS4000 Trigger Start Torch + MAP Gas
1/2 inch sockets, Breaker, Cheater Pipe, and BFH
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post #27 of 161 Old 06-30-2016, 03:35 PM Thread Starter
Rob K
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That's likely what I will do. Paint everything I can get to and use Fluid Film or some type of oil that will wick into the seams. Sounds like a solid plan.
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post #28 of 161 Old 07-01-2016, 01:10 AM
Candymancan
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Yeas adding more holes helps alot for ventilation and drainage.. I did the same to my 5.9 and 4.0 rockers. The 4.0 sadly has rocker rust on the passenger side but the drivers is ok, and my 5.9 has a tiny bit of rust but not enough to really worry me atm.. So i drilled a bunch more holes.

I gatta tell you the rockers on your Jeep are very small lol.. With the plastic removed and pics of the underside these Jeeps dont even have real solid frames anymore i guess. They are like sections of plates and stuff.. I wonder if thats for like "crush" zones
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post #29 of 161 Old 07-04-2016, 08:50 PM Thread Starter
Rob K
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Never got a response from Magnet Paints. I followed their instructions exactly for going over existing paint. Hopefully it holds up. Will be a horrible experience if it doesn't. Can't tell you how many hours I spent on the little bit that I did. Quite a few. It was a pretty messy job painting upside down. Figured out the best way to do it is to roll on the paint and then brush it. I thinned it out pretty good, but it still left brush stokes since it was starting to set up almost instantly as I applied it. Which means there's not a uniform coating thickness. Painted everything twice and the welds/seams/corners got three coats. Used probably 2/3rds to 3/4ths of a quart. Need to get a couple more cans before I can continue. Would be nice if I could find it local.
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post #30 of 161 Old 07-11-2016, 04:43 PM Thread Starter
Rob K
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Here's how I took care of the broken clips for the rocker covers.
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