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Suggestions for undercoating?

BALTANAKT

NAXJA Forum User
Location
Berthoud, CO
Hey guys,

Re-coated the inside of my rear fenders using the professional grade Rusto stuff.

It went on super thin, so now I am thinking about doing another coat of something over top.

What is the best undercoating these days?

Is there anything that goes on thick and stays black?
 
If you have already applied one coat your pretty much stuck with whatever based the first coat is. What exactly did you apply?
 
Yeah I might end up striping it. Used this stuff.

715nM0%2BUWuL._SL1500_.jpg
 
For over 40yrs I've had great luck with 3M Body Schutz but I don't believe it comes in a spray can. For better protection paint it with bed liner first.
 
I'm kinda skeptical about the description though:

  • Prevents valve seat damage in engines designed for leaded gasoline
  • Prolongs the useful life of older engines without updated valve seats
  • Also cleans carburetor deposits and injectors, safe for catalytic converters.

Lol thats an Amazon vendor quirk I guess.


https://www.3m.com/3M/en_US/company.../3M-Undercoating/?N=5002385+3293242023&rt=rud

Ignore the different color can 3M 08881 is what im suggesting. The Amazon photo is accurate, but I wouldn't put it on anything other than undercarriages haha.
 
If you want heavy duty authentic no s#!t old school then Bituminous coating is what what your looking for. It can be brushed, rolled, dipped or sprayed. Also it can be thinned for use in touch up guns.
 
If you want heavy duty authentic no s#!t old school then Bituminous coating is what what your looking for. It can be brushed, rolled, dipped or sprayed. Also it can be thinned for use in touch up guns.

Man, the only roll on stuff I see is $250.

Anybody ever use Flex Seal before?
 
Are you being serious? Ha? Cause that made me chuckle

When you ask for undercoating, what are you trying to accomplish?

Trying maintain the underside of the XJ so it will never start rotting. So basically prevent damage from stones, rust formation, etc. Would be nice to have a product that was UV light resistant so it didn't turn gray within a year.

Overall the XJ is in such great shape, I hope to keep this thing forever, so trying to maintain it with that in mind.
 
I just sprayed on my first coating of the Rustoleum rubberized undercoating yesterday, I am confident in one thick layer of the stuff but I will add a second coat when I get home. Why not just spray on multiple coats and keep it cheap? I prepped, painted and then sprayed the undercoating. Seems sufficient enough to battle Salt Lake winters in
 
I just sprayed on my first coating of the Rustoleum rubberized undercoating yesterday, I am confident in one thick layer of the stuff but I will add a second coat when I get home. Why not just spray on multiple coats and keep it cheap? I prepped, painted and then sprayed the undercoating. Seems sufficient enough to battle Salt Lake winters in

Hey MG2000XJ, what exactly did you do prep wise? Like the OP, I have a 96 in great shape and want to add a layer of protection so I can keep this for a loooong time.
 
Trying maintain the underside of the XJ so it will never start rotting. So basically prevent damage from stones, rust formation, etc. Would be nice to have a product that was UV light resistant so it didn't turn gray within a year.

Overall the XJ is in such great shape, I hope to keep this thing forever, so trying to maintain it with that in mind.

3M has worked quite well for me, it's been on for many years.

Success of anything used to coat your vehicle will come down to prep work. If you really want durable this isn't undercoating but: https://www.amazon.com/Raptor-Tinta...ocphy=9028912&hvtargid=pla-494060002021&psc=1

Also a note on the 3M, it's not so much a rubbery can of crap, but an asphalt type mix, it's not similar to rustoleum or box store name coatings. I can't speak to the previously mentioned 250$ stuff. Flex seal will last a week if your lucky, better for plugging a leak interior or such.

We're you think more wheel wells or are you coating the entire underside?

If your doing the whole undercarriage the 250$ stuff might be better value for covering more surface area.:cheers:
 
Hey MG2000XJ, what exactly did you do prep wise? Like the OP, I have a 96 in great shape and want to add a layer of protection so I can keep this for a loooong time.

Depends on where I was spraying it. Just behind the rear wheel wells, where the shackle box is. I was dealing with a little bit of rust so I used a wire wheel on the rust, then a scotch pad to scuff the remaining paint/primer as well as some JB weld to fill the gaps between the pinch welds, once dry, I scuffed again, wiped with mineral spirits and spray painted. Once the paint was dry ( a couple days later), I scuffed the paint and sprayed thick coats of the undercoating.

On the wheel wells, which I not yet undercoated, I will probably take a dish scrub brush with stiff bristles with me to the DIY carwash, pressure wash the existing undercoating and scrub, wash again to clean off any dirt, dry it over a couple warm days and scuff any exposed paint and then spray the undercoating.

Someone might have advice or insight into a better way but this is how I've approached it. When I say thick coating, I'm spraying this stuff up close and it's almost to the point where it's running. I'm spraying places where I don't care if it has runs in the coating but so far it's been thick enough that it doesn't run while leaving a heavy coat I can dig a fingernail into.

If you're experiencing extremely thin coats, I'd spray closer and be liberal with the stuff. Wheel wells don't need to be perfect.

Hope that helps.
 
Depends on where I was spraying it. Just behind the rear wheel wells, where the shackle box is. I was dealing with a little bit of rust so I used a wire wheel on the rust, then a scotch pad to scuff the remaining paint/primer as well as some JB weld to fill the gaps between the pinch welds, once dry, I scuffed again, wiped with mineral spirits and spray painted. Once the paint was dry ( a couple days later), I scuffed the paint and sprayed thick coats of the undercoating.

On the wheel wells, which I not yet undercoated, I will probably take a dish scrub brush with stiff bristles with me to the DIY carwash, pressure wash the existing undercoating and scrub, wash again to clean off any dirt, dry it over a couple warm days and scuff any exposed paint and then spray the undercoating.

Someone might have advice or insight into a better way but this is how I've approached it. When I say thick coating, I'm spraying this stuff up close and it's almost to the point where it's running. I'm spraying places where I don't care if it has runs in the coating but so far it's been thick enough that it doesn't run while leaving a heavy coat I can dig a fingernail into.

If you're experiencing extremely thin coats, I'd spray closer and be liberal with the stuff. Wheel wells don't need to be perfect.

Hope that helps.

Yep, that helps. Going to start under the floor boards so will power wash and use a brush. Just a tiny bit of surface rust so will put some naval jelly on that and then prime and coat with the undercoating.
 
Fluid Film every year. It isn't permanent, but it doesn't require a lot of tedious prep work. I have a 98 with zero rust b/c of the product.
 
Honestly. Strip it down and buy that $100 roll on bedliner. You won't regret it. I gaurentee it !!! Roll it on thiccc with 3 C's is the best tip
 
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