Painting technique for a new diff cover?

dgeist · **Posted:** Sat Apr 24, 2010 12:17 am

So, my new rear diff cover should arrive any day now. It's the rockcrusher model, so it's single piece forged steel and unfinished. What's the best way to paint the cover to get the best longevity and rust protection?

I'm figuring some good quality rattle-can primer and either satin or flat finish paint. Do you need high-temp engine paint for a diff cover? I'm assuming there's no reason to paint the inside (and lots of reasons not to), so do I just lay it down on cardboard or paper and paint all the exposed surfaces (including the insides of the bolt holes)? and then let the bolts clean out the paint for me or is it worth doing blocking and taping of those surfaces along with the drain plug threads, etc do avoid chipping and peeling?

I know I'm over thinking it a little, but I want to get it right and have the finish last a long time.

Dan

JeepinJarhead03 · **Posted:** Sat Apr 24, 2010 12:26 am

take a Q-Tip and stick it in some vasoline and run it around the inside of the bolt holes if you want, otherwise, it's not going to hurt anything

i pretty much sprayed mine down with brake cleaner and let it dry then shot a coat of rustoleum rust performer black primer

since most paint can streak / discolor when it comes in contact with axle grease, after changing fluids and reinstalling the cover, i just spray it down with brake cleaner again and re spray it with a few puffs and call it a day

JL Rockies · **Posted:** Sat Apr 24, 2010 11:56 am

Powder Coat would be superior.

03CDKJ · **Posted:** Sat Apr 24, 2010 12:07 pm

I find it easier to paint after installation.
Between RTV and Gear Oil, it's hard to not mess up the paint when installing.
Give it a few coats of primer, Then install....If you get any RTV or Gear Oil on the primer you can just sand it down.... And not mess up your nice new paint.
:2cents:

Boiler · **Posted:** Sat Apr 24, 2010 12:57 pm

Might take a scotchbrite pad / steel wool / sandpaper and rough up the surface slightly if it is smooth. Then wash that and the hand oils and such off with isopropyl alchohol or even brake cleaner.

Set it so the outside is facing up sitting on a piece of cardboard on the top of a garbage can, out away from anything you don't want overspray on. In the sun is good, the warmer and drier the better. Breeze is good too.

Next I'd use rustoleum clean metal primer if it is not rusty, or rusty metal primer if it is. Actually I use rusty for most because I have it, but I think clean would be better. Once the primer dulls / looks dry, but a coat of your color on. Start with the edges and holes and hard to hit spots. Don't overdo them, if you do several thin coats in this manner, you'll get them all colored. Wait 45 mins to an hour between color coats.

I'm not a pro rattle can sprayer, this is just my method and it's worked ok for me.

DirtyKK · **Posted:** Sat Apr 24, 2010 1:42 pm

I would use duplicolor truck bed coating you can get at any auto store. It makes a terrible truck bed coating, more of a textured paint. Requires no primer, its tough and easily touched up. I painted my rockcrusher, sliders and soon to be more (secret for now). I was recommended it by a fabricator of aftermarket off road parts and its worked well for me.

valvestem · **Joined:** Thu Jul 07, 2005 7:01 pm **Posts:** 222

I suggest some self-etching primer, and a good quality compatible paint.

Diggerfreek · **Posted:** Mon Apr 26, 2010 11:33 am

On my cover, I used a rustoleum primer and then used some 2 stage paint that napa mixed up for me in a spray can. Then I used a clear coat. Still looks like new after a winter of mag chloride

haulin5 · **Joined:** Tue Sep 29, 2009 2:53 pm **Posts:** 116

Dan, just a word of caution if you're painting outside........

I obviously don't do much of anything to my Jeep, but I'm refinishing our kitchen in my spare time. This year has been particularly rotten regarding pollen. I know from watching the Masters that Georgia was absolutely horrible, and the yellow sticky mess was everywhere. I had just finished polyurethaning an entire cabinet & placed it outside to dry in the sun & breeze, like I normally do, and it was almost ruined by pollen sticking to the finish.

This year I've had better results by keeping everything in the garage to dry.

JeepinJarhead03 · **Posted:** Mon Apr 26, 2010 2:48 pm

yeah, that looks better than mine

but then again, i use flat black primer on everything

it's very good for protection vs salt and stuff, very easy to touch up, matches the double microtex powdercoat that's on my bumpers dang near EXACTLY, and is cheep, cheep, cheep

and i usually carry 2 or 3 cans of it everywhere i go lol

I keep things very subdued, only thing on my vehicle that reflects light other than the 'winders' is the paint and when it's clean, photos don't do it justice

tommudd · **Posted:** Mon Apr 26, 2010 3:30 pm

Digger
Whats the deal with all of the rust?? :shock:

Man I thought you cared about your ride more than to show or have rust.
Chris would never approve!!!!
:-)r

03CDKJ · **Posted:** Mon Apr 26, 2010 3:37 pm

PPPPFFFFFFFFTTTT!
Amature Hour!!! :goink:

Diggerfreek · **Posted:** Mon Apr 26, 2010 4:27 pm

That rust is the remains of the copper RTV I used when I did my diff the previous time

When I open a diff up, it isn't going to leak afterwords :twisted:

JeepinJarhead03 · **Posted:** Mon Apr 26, 2010 4:48 pm

me either, i use lubelocker gaskets

Diggerfreek · **Posted:** Mon Apr 26, 2010 4:53 pm

JeepinJarhead03 wrote:

me either, i use lubelocker gaskets

But that takes all of the fun of cleaning the diff up with brake cleaner in a confined space :dizzy:

JeepinJarhead03 · **Posted:** Mon Apr 26, 2010 5:01 pm

i still do that

after i reinstall the cover and before i respray it with primer

lol

dgeist · **Posted:** Tue Apr 27, 2010 10:46 pm

haulin5 wrote:

Dan, just a word of caution if you're painting outside........

I obviously don't do much of anything to my Jeep, but I'm refinishing our kitchen in my spare time. This year has been particularly rotten regarding pollen. I know from watching the Masters that Georgia was absolutely horrible, and the yellow sticky mess was everywhere. I had just finished polyurethaning an entire cabinet & placed it outside to dry in the sun & breeze, like I normally do, and it was almost ruined by pollen sticking to the finish.

This year I've had better results by keeping everything in the garage to dry.

Unless you've been here in April, you have NO idea...the TV coverage can't possibly do it justice, not even the 3D coverage this year

The tree-sperm falls for about two weeks, then the oak and other hardwood stamens (little fuzzy plant caterpillars all over the place) for a week after that. Thankfully we usually get a lot of rain in late April and June and everyone washes their cars.

Point taken. I'll remember to do the finish coats in the garage.

All: would the use of engine paint (temp and solvent resistant) minimize the discoloration from oil and cleaners? I'm probably just going to do black anyway, or maybe metallic silver to match the body color.

Dan

dieselenthusiast · **Posted:** Fri Apr 30, 2010 1:05 am

DirtyKK wrote:

I would use duplicolor truck bed coating you can get at any auto store. It makes a terrible truck bed coating, more of a textured paint. Requires no primer, its tough and easily touched up. I painted my rockcrusher, sliders and soon to be more (secret for now). I was recommended it by a fabricator of aftermarket off road parts and its worked well for me.

Do you have any pics?

DirtyKK · **Posted:** Sun May 02, 2010 12:25 am

Diggerfreek · **Posted:** Sun May 02, 2010 12:30 am

Does that diff cover clear the factory track bar Dirty?

Painting technique for a new diff cover?

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