Frame Rust?

That's what i think too. Maybe just a wire brush to the areas that are flaking when it warms up.

 

*Cries in Michigan*

 

Ended up getting a deal on some cans of black fluid film. My initial brushed on FF coating during the diff service has held up really well, some spots where rust has flaked off and left exposed metal. Plan on doing a full rinse of the underside, no soap, either just water or salt gone to rinse everything out and not strip off the existing layer of fluid film. Let it dry over night, and wire brush, then touch up with the black cans and reapply to the inner frame rails with my 360 wand.

 

Anyone every use a needle gun over existing fluid film?

 

Sounds like you have concerns that some rust still exists. I would do whatever is necessary to remove all you can find, regardless of what FF is on there now, then reapply once you're confident you've dealt with all the rust. Otherwise, you might be chasing rust spots constantly.

 

Fluid film will isolate the rusty areas. I would use a wide flat head screwdriver or hard metal scraper to knock off any areas of very scaly rust. Don’t go crazy…if it doesn’t come off easily with scraper, the fluidfilm will isolate the air from rusty areas and slow it down or stop it. Fluid film is thinner than woolwax which is a good base layer. After a couple of months you can add layer of woolwax over the top, which is thicker and will stay longer.

 

It's not terrible. If it bothers you I'd just use a die grinder with a wire brush to remove heavy rust.

Spray bare areas with Steel It.

Use your choice of under body protection from there on out. Fluid film, wool wax, etc...

 

Alright. Finally had some time to do a deep dive into this a bit further. A bit of a recap of events:

Shortly after purchase i wanted to get some type of coating on the vehicle before the warmer winter weather. (Where i live they use sand for majority of winter, only when it gets warmer they'll switch to salt/sand combo) I was able to brush on fluid film from the can and use about 4 cans with a 360 wand to coat the inside of the frame rails/rocker panels. This coating held up very well, but without the proper surface prep fluid film could only do so much. Small areas of flaking would become exposed into the spring. Specifically the weld area and some spots on the rear axel.

This initial coating provide me some peace of mind, but know i would do some more intensive prep this spring. After researching and taking @McSpazatron advice on not being too detailed or obsessive on it, i decided to use a combination of Salt Gone spray, metal gasket scraper, wire brush, wire wheel/angle grinder combo. wire wheel/drill combo. Really wanted to get a needle gun, but didn't have the desire to spend the money on getting one.

This total project took about 12 hours over 3 days. I really didn't take enough pictures.

Day 1: Starting to chip away at the rust (most time intensive 6-7 hrs) Very happy to find that all the rust was very early on it's development. With 1" gasket scraper and wire brush i went over most of the loose surface rust, lots of small scale came off and gave me a good chance to really poke around everything. Then started along with the wire wheel/angle grinder working along the welds, rear axle, control arms. This brought a lot of areas down to the bare steel. While good to see no big issues i want to be mindful and not remove too much of the factory coating unnecessarily. The wire wheel/drill was great for getting into the tighter spots that the angle grinder could not.

Day 2: Under side salt spray (1-2hrs). This was probably the least impactful step, however it provided peace of mind knowing i was clearing out all possible contaminates before applying fluid film. Purchased a bottle of "Salt Gone" from Amazon, it attaches directly to the hose and distributes the product while spraying. I specifically chose those product through reading forms mentioning that it would not remove existing coatings of fluid film or other biased coatings. Sprayed and rinsed off thoroughly, let dry with a highway drive and sitting over night.

Day 3: Fluid film application (3-4hrs). I used 10 cans total, 4 for inside the frame and holes, 6 for the exterior of the underside. I've always used fluid film clear, but deiced on using black this time. Beginning with the 360 wand i applied to every hole on the underside and inside the frame rails/rad support/ spare tire holder etc. With my previous inner frame rail coating a few months back i felt really good about the "inside" of things having a really good coating. One plus to using black fluid film is you can definitely tell where you have and haven't sprayed. I decided against painting the sanded surfaces as there was no way i was going to get all the rust off and i didn't want to trap any of it under paint. I've seen the build up layer that fluid film creates over the years and I'm confident it would protect the exposed areas. On ramps starting from the rear, i worked my up spraying all the metal surfaces. Very happy with how the coating turned out.

The pictures I'm uploading are of post surface prep and obviously post spray, prior to the drive down a gravel road.

 

Excellent work! Once you cleaned the rust up, you’re right, it really doesn’t look that bad at all. And with the woolwax on, it looks beautiful.

Now you’ll probably need to buy a quart or gallon pail of woolwax to have on hand for touch up. I also use it to reapply a heavier coating after the first layer has gotten set up a bit, which really starts to build “crust”. Just get a cheap painters brush and glop it on whenever you’re doing any maintanance.

 

Appreciate the kind words! Fluid film for now, no Woolwax yet. I still have the half 3.78L can of fluid film that's I'll continue to use for touch ups through the summer.

 

Good work!