Rear crossmember rust cleanup (1 Viewer)

[CharlieS]

I'm about to install a new bumper and of course, have the typical rear crossmember corrosion. I want to clean it up before the install, since I don't plan to have it apart again anytime soon.

I've definitely seen worse, but I want to get ahead of it.

What have people done that was effective?

Plan A is wire brush, flap wheel, rustoleum rust converter, rustoleum professional enamel black top coat.

I've considered one of those cheap harbor fright sand blasters, but I'm sure I'd make a mess and probably hurt myself with one...

Any success stories out there?

 

[CharlieS]

Would a needle scaler be worth picking up?

 

[doru]

The good news is that it is not bad. Great idea to address it at this stage.
The plan sounds good.
A sand blaster like the cheap tank based one from HFT can help a lot. It is cheap but good. You need to buy a few extra from HFT to make it proper but all is cheap. It does make a mess so you should do it outside. That presents challenges if it rains a lot where you are.
One thing to address is inside the frame. If you have access try using some of the rust conversion products designed for that and use some frame saver products - wax based, after. What's not great about those is the danger of fire if you need to weld the frame in the future. But they do work on protecting the frame.
On light rust areas you can use a chemical rust remover to save on prep work labor and not shave off metal unnecessarily. I like the Eastwood one sold in gallon jugs, that is fast, cheap, doesn't require washing off (removes the issue with flash rusting), and leaves a protective coating. It is corrosive (acid based) and it does require a lot of acetone to wipe it off - toxic. I still like it a lot.
Take good care with masking and get big plastic sheet from hardware store to cover the car. Overspray is easy to get, hard to clean, and if bad expensive to fix. Plastic is cheap. If you use sand blasting protect the areas around the frame with some heavy plastic sheet or cardboard, not just masking.
Good luck and make sure to post back with the results and what you learned.

 

[Tex68w]

It's incredible how easily and quickly these things rust, but of course it's all relative to where you live and how well you maintain them. Yours isn't that bad, I'd clean it up and paint and move on.

 

[4gotalot]

The rules to prevent surface rust: Starve the surface of oxygen or water or both to prevent oxidation. (Just trying to keep it simple)

Use a small wire brush to remove the loose stuff, spray on a thick coat of LPS 3. Move the LPS 3 around with a 1" paint brush (save paint brush) for other places under the frame and cast parts like KDSS parts. I only have to re spray the stuff on again if an area gets blasted by lots of slush after a couple of years. It will look like that again if you do not prep the surface well, use a quality primer and a quality paint. It will look better with paint, but the LPS 3 will stop the rust and is a lot less work.

If you sand blast the rust you will be exposing more metal than you started with.

 

[Heckraiser]

I would avoid rustoleum products at least as a base layer/rust converter, I have had pretty poor experience with them in general. I can't say exactly what's best, but I've used POR-15 and topped with general purpose primer and black spray paint (may have actually been rustoleum paint) and it worked well as long as I owned that particular cruiser.

 

[kcjaz]

I just wire brushed mine and hit it with POR15. I should have washed it with degreaser but didn’t think about it at the time. Mine wasn’t too rusted. Mostly just dirty.

 

[Heckraiser]

I should also mention POR-15 is not UV stable, which doesn't matter so much under a bumper (except maybe where the hitch is exposed), but best practice is to cover it up with a layer of paint.

 

[CharlieS]

Thanks for all the info everyone.

Based on the way kcjaz's crossmember came out (looks like new!!), I think I'll go the POR-15 route, with a topcoat, just to be safe.

 

[kcjaz]

Thanks for all the info everyone.

Based on the way kcjaz's crossmember came out (looks like new!!), I think I'll go the POR-15 route, with a topcoat, just to be safe.

To be clear, I used the POR15 top coat product which is UV stable. It’s what I had on hand. In my case, I figure it is enough corrosion protection. Bullet proof is POR15 rust preventive plus top coat. Overkill IMO here.

 

[CharlieS]

Oops, I just bought the POR-15 rust preventative. Shouldn't hurt to do it this way. This area is so prone to rust that every little bit should help.

 

[yonah]

If you want a clean, OEM-like black frame, Plan A method and then apply a coat of either Surface Shield or Fluid Film both inside and on the outside of the frame.

If you want to forgo the paint altogether, you could descale the heavy rust and apply SS/FF product sans paint. Either way, further oxidation would be prevented by the oil barrier that denies hydrogen and oxygen access to the metal (as mentioned above).

I like the lanolin products as they creep into the cracks/crevices of the metal and will self heal after contact from road debris. Surface Shield seems to adhere better than FF and in this application, would be a one time job. That rear crossmember doesn’t receive a lot of road spray from your tires.

Both products can be found at Home Depot last I checked.

 

[CharlieS]

I'm not a fan of the spray on rust preventative products like that. I have no doubt they are incredibly effective, but I work on my own vehicle and they make a mess every time you touch the underside. Even if I didn't do my own work, I can't imagine subjecting mechanics at shops to that hassle and mess. We bought a camper whose frame had been treated with fluid film and I curse every time we use it because the stuff gets all over.

 

[bronc076]

Charlie I've done a lot of sandblasting and it is the best way to remove rust. It's messy and you need a good compressor to keep up even with a little HF unit. I blasted a majority of my bronco years ago. And the inner fenders recently. Long sleeves, face protection, good gloves, you can't really see what you are doing. It sucks, but what a nice finish it leaves.

factory frame paint sucks.

Kcjaz, that looks nice!

I'd do what KC did if I didn't already have the sandblasting gear!

 

[Fisher23]

wire brush or wheel works good.
or if you feel lazy spray it with oven cleaner.. let it sit and it will wash off.

 

[bigredmachine]

Would a needle scaler be worth picking up?

for that no, it looks like its mainly surface rust. the scaler will be better with heavy rust getting that top layer off and you would still need to use a wire wheel or something like that if you wanted to bring it down to bare metal to prime and paint

 

[KLF]

If it were me, I would do exactly as you describe in Plan A, but then after the paint was fully dry I would apply several coats of Amsoil Metal Protector. I have done this to mine since I got the truck and it still looks new, not a speck of rust anywhere. Yeah, I keep some nitrile gloves handy in the drawers for when I have to install or remove the trailer insert.

I have one of those Harbor Freight sand blasters and it works better than I expected. I keep black beauty in it.

You and your neighbors will hate a needle scaler. Very noisy.

 

[CharlieS]

Thanks, everyone for the great advice. I have a plan of attack and will try to post a picture or two once I get things cleaned up and painted.

 

[yonah]

I'm not a fan of the spray on rust preventative products like that. I have no doubt they are incredibly effective, but I work on my own vehicle and they make a mess every time you touch the underside. Even if I didn't do my own work, I can't imagine subjecting mechanics at shops to that hassle and mess. We bought a camper whose frame had been treated with fluid film and I curse every time we use it because the stuff gets all over.

Yeah, that’s the con to the pros of lanolin rust preventative products. If you haven’t selected a method, maybe coat the inside of the frame with FF and the outside with something dry, like Cosmoline (CRC Rust Inhibitor). When it dries, it looks like dark brown candle wax.

Either way, you frame looks pretty good and this should be an easy job.

 

[CharlieS]

Had a 24 hr bug, so didn't get to this project yet, but picked up some supplies before I got sick.

The disk is designed for a grinder for heavy rust and paint removal. I have other wire brush tools and flap disks that I can also use.

I got the six pack, since in my experience the stuff hardens and makes it tough to reopen containers. I figure I have lots of other rusty welds that I can clean up and treat over time.

I got the rust stop kit so I had the proper prep chemicals to get through the crossmember project. Figured if I was going to bother, I might as well follow their full instructions.

I'm sure I'll need more degreaser and metal prep, but I can order it online more easily than I can find it locally. The auto parts stores around me either don't seem to carry it on their shelves, or they only have these kits.