Sandblasting Frame

Wrangler frames are galvanized. You could take the zinc right off. Why?

Earle

You could skip the sandblasting and paint it with POR-15. That way you'd only need to degrease it and chip off any flaking material. POR sticks to rusty metal better than it sticks to shiny metal. You should topcoat it with another paint.

If you use POR /follow the directions exactly/ or you'll waste your money. They aren't kidding about it curing in the can while open, about it gluing the lid shut between sessions, or about sticking to your skin.

Lovs2fly wrote:

I'll second that.

Dave Milne, Scotland '91 Grand Wagoneer, '99 TJ

I would think to clean up all the rust then start new. If you have a clean frame and then do the proper job of coating or painting you will have a great look frame rust free.

If you have rusted areas, then I fully agree, but just don't take any zinc off.

Earle

I would sandblast the frame and then use POR-15. That seems to be the best. Check out the instructions at

All for one and one for all

Agreed. I did my frame on my truck about 5 years ago now. Although it isn't an off-road vehicle, the POR-15 still looks the same as the day it was applied. A very good product. If you do sandblast, don't worry about getting every little speck of rust off of the frame. It is not critical with POR-15. The main thing is to get all of the grease and oils off, plus any loose scaly material, such as rust. It you treat the cleaning like you would any other automotive paint job, your work will last a long time.

Chris

There's really no such thing as blasting and NOT taking zinc off unless the blaster is a real expert at doing so. The exception to this is using a weenie little blast unit that doesn't strip the zinc, but als doesn't really burn everything off the steel clean as new. It might look good with a little blast, but if you're using anything less than a 1" ID blast hose, you're not really stripping. I've worked in an industrial oxide blast room and I've probably done 100+ auto frames. I've also blasted more miles of galvanized iron railings than I can ever remember so I'm very familiar with blasting zinc.

Have it blasted with aluminum oxide. It's very abrasive and will strip everything but steel off your frame. If there's any rot, it'll also burn all the rust off it and leave it in satin-grey - that's what color steel is when stripped. Weld up any damage/rot holes left from the blast, then have it blasted again to strip 100% of welding slag away. You'll be very happy wth the results no matter how picky you are about details this way. Plastic blasting wil only take paint, most lead and bondo off. It does next to nothing for rust removal, so don't waste yout time/money on it with a frame.

Start with a good epoxy primer once the frame is blasted clean. "Green death" acid based self-etching is the best, but kinda hard to find, toxic as all get out (until dry, then it's safe) and expensive. The tradeoff to the bad is that it protects as well or better than anything you can use for any price. The blast facility I worked at did a ton of stuff this way for the military - we did it better than even they could.

Choice of paint is up to you, but stick with an epoxy if you prime with epoxy. Most auto paint is epoxy anyway. You can also powder-coat or bedliner over primer and it'll last practically forever. I'm going to do this (blast/weld/blast/prime/bedliner) to my 50 Willys Wagon frame. It's not a showcar, but I only want to do this once. ;)

Cheers, - Jeff G

Sticks better to rusty metal? Not really.

If it's aluminum oxide blasted professionally, the surface of the metal is very coarse and will hold POR or any other coating better than you can imagine - far better than rusty metal and you're assured of ALL scale being removed with blasting. Don't let your frame sit at the blast shop for more than 24 hours after it's blasted. It'll start rusting from the water in the air. Not too bad in the winter, but I've blasted things in the shop at 5pm and had to reblast them in the morning because it was humid overnight. Get it painted immediately even if it means hauling the frame straight from the blast booth to the paint shop. Most blast facilities will at least prime stuff for you. Don't go the hillbilly route and prime something and delay getting it painted. You'll have rust starting under the primer that you can't even see (it's porous and can actually pull water from the air, holding it on the metal surface). Primed metal only prevents rust about 2x to 4x as long as bare metal in many cases.

POR works on the theory (and application) that it seals the surface so well that oxygen can't reach the metal and rust underneath it so rust (oxidation) can't continue. If you have a boxed frame, it'll rust through from the other side. POR doesn't change rust into anything else, only God & wizards can do that. :D

Just don't try AO blasting on sheetmetal unless you're dealing with a true pro in the field handling the blast. It's real easy to punch holes in anything you don't warp into unrecognizable shapes from excessive heat from the blast. ;)

Cheers, - Jeff G

[quote] WHAT IS THE BEST SURFACE ON WHICH TO PAINT POR-15? POR-15 likes rusted surfaces best. Seasoned metal and sandblasted metal are also good. POR-15 does not adhere well to smooth, shiny surfaces, but will adhere well to those surfaces with the proper preparation. [unquote]