SeniorXJ

-Few quick questions as i get prepared to start installing ruff stuff stiffeners & plating the unibody from front to rear & topping it off with aftermarket bumpers.

-My 1st question is, whats best to clean the unibody with?? This jeep has NO rust on it anywhere, (ull see in the build thread), & so i have wire wheels & 80grit wheels on the grinder, but i think the 80 grit takes too much material off, especially when theres no undercoating on this XJ. Is there a lighter flap wheel or some other type to use??

-Second, i keep thinkin that once the material is cleaned & the stiffeners are installed, what happens to that unprotected material within the plating?? I was thinkin of using weld thru primer to protect all of the metal. Any one wanna chime in??

Thanks!!

03ghosthemi

That's about the same way I did mine. Torch and steel putty knife for any spots of under coat, 36 and 80the grit for paint and any little rust spots. Used weld through primer on frame and stiffeners. Then welded it up. The only rust I had on mine was a couple of light surface spots. Just remember when sanding go real easy. Like you mentioned real easy to remove to much material.

PingPong

If you have no rust I would wire wheel it.. and only wire wheel it enough to remove the paint. Also remember the metal on the jeep is galvanized.. at least on the older ones and wear a respirator. It is an easy way to get lead poisoning

SeniorXJ

Mines a 98 so should i still be concerned with lead?

PingPong

Its not lead.. it is the galvinized metal creates a chemical reaction when welded/cut with heat or cut off wheel. We use to call it lead posoining when I worked as a pipefitter. Drink milk before cutting/welding and waer a respirator.


If you weld on it and it makes a white feathery smoke that gets on everything, or the slag has a greenish tint it is galvanized.

Thekid320

Right on with the milk not to many people know that of not it will make you sick or flu like symptoms

Gionet

primer is not a sealer it is pourus, so water will go thru it and rust will happen.

There is really no way to perfectly seal everything and still weld to it. The only option would be paint everything with a good chassis paint, then only grind the paint off where you are gonna weld, this minimizes the amount of bare metal, but is also a pain, and isnt flawless.

SeniorXJ

Already bought a gallon of Chassis Saver & i have 2 cans of spray on bedliner, & i plan to coat everything after the install & plating is done.

Question, are there any of u guys that have wire wheeled/cleaned up those rails & just welded the stiffeners on??

Trev1006

I made my own mj braces and just welded them on. I work in the professional fab and machining industry and in our experience weld thru primer can contaminate welds making them weak. It also takes penetration power away from your welder as it uses that heat to blow away the primer instead of heat the metal. I bet most things welded with burn thru primer wouldn't pass the BFH test. If you have light body work to do that is where your burn thru primer is nice. Another trick is smear your underbody welds with liquid nails, they will NEVER rust. Just remember the cleaner the metal the better/stronger the final product.