Undercoating

[87Warrior]

What are your opinions on the different undercoating options out there?

 

Soon my trucks undercarriage (frame rails, floor pan, inner fender-wells) will be blasted and covered with POR15. Initially I had planned on top-coating using the POR15 Chassis Coat. As I get more meticulous and picky with what happens to my truck, I have started to wonder if a rubberized type of undercoating would be a better option. Obviously if I go this route, the initial coat of POR15 would be treated with their Tie coat primer then undercoated.

 

Either way the undercarriage will have two layers of protection. What I am after is understanding the different types of under coating out there and what their purpose is. There is a reason vehicles are not just painted with a durable paint on the chassis, but why? Does the rubberized coating prevent corrosion? Chips? Sound deadening? What is its purpose?

 

Lets say the consensus is that undercoating is not only beneficial, but necessary, what would you use to coat the undercarriage of your truck?

[jimoshel]

When they first started undercoating it's primary purpose was rust prevention. Than they began the sound deadening spiel. Properly applied it does the job it was intended for. If not properly applied moisture gets trapped under it and hastens the rusting process. Personally I don't undercoat and use the car wash whenever I think it needs it. Mostly after driving on salt treated roads. If I was to undercoat, I would use the rubberized method.

[87Warrior]

Thanks for the reply Jim. What you said is very logical.

 

Does anybody have a recommendation for a quality rubberized under coating? I would like to research some of the recommended brands.

 

This project is at least a month out.

[Automan2164]

I have used this stuff at work, it's called "Atcoat" or "Atcote" rubberized undercoating. Don't know if they are still around, but I used it to coat a hanger for a calcium chloride tank on the back of one of our plows and it turned out nice. I liked the even dimpled coat too. Don't know how strong it is, as we never put the rack in service, but it looks good... If you want, I can take a pic of the can, and the rack tomorrow if I have time.

 

Rob L.

[brdhntr]

i used to run a shop and we did undercoating. i have personal experience and training in applying it.it's a great way to go and does help with rust. the catch is that they don't tell you it comes off under certain situations. if you drive alot of gravel, the kicked up rocks and sand from your tires sandblasts it right off in the wheel weel. since that's a prime rust area, that blows the benefits right there.on frames and underbody areas, you have to make sure you apply it to the holes in the frame. the catch there is that the inside of the frame still gets moisture and rust from the inside. it is impossible to cover the inside of the frame or the total frame in any area. the other thing with it is that if you ever want to mount something or use the holes, you will have a mess to clean up and will have to undercoat the new bolts. every time the bolt goes in and out or moves, that wears the undercoat off.

 

i could go on withthe good and bad things about undercoating. so what would i do? on a brand new vehicle, i'd have them do it and get a warranty for wear so they have to reapply it in the fenderwells. the dealer stuff in really the way to go as it is far better than anything available in a spray can. i would also make sure it is put on thinck. at least a double coat.

 

in you situation, i'd por15 it, then treat it witrh the prep primer and use bedliner. you can roll it on and get it whereever you want for a reasonable price. it will look nice and cleans up easy with an underside wash at the car wash. i think it's the way to go.

 

 

but that's just me. :smart:

[87Warrior]

in you situation, i'd por15 it, then treat it witrh the prep primer and use bedliner. you can roll it on and get it whereever you want for a reasonable price. it will look nice and cleans up easy with an underside wash at the car wash. i think it's the way to go.

You know, this is an option I am considering. I have understood that bed liner is not a replacement for undercoating like a lot of folks think. It usually does not 'stick' as well on the under carriage because folks spend less time preparing and whined up with problem area. However, I can see the same thing happening with undercoating as well. I will be starting basically new, with a solid POR15 coat. My speculation is with a good POR15 coat, anything applied over it will just be additional protection.

 

My truck has/had the original factory rubberized undercoating. Having grown up in rural KS, gravel roads are the normal, I did notice my MJ transmitted much less noise when gravel hits the under carriage than my TJ does (which only has a painted under carriage). I also plan on taking the truck through Colorado's back country trails/roads, which often times are several miles of fine gravel. Now my mind wonders if a tough/hard bed liner would provide the same 'rock-to-metal' cushion as a rubberized undercoating. Yes, I do realize the rubberized undercoatings do turn pretty solid them selves.

 

Maybe I should do small-scale product testings on some of the junk body panels I have laying around. Could make for an educational weekend :hmm:

[brdhntr]

playing around is always fun, so you can try some stuff out on the extra metal you have around. you may have a little less noise with the undercoat, but i don't think it's enough to cancel out the extra protection and better resistance to gravel and such you should get with the bedliner. the bedliner will be easier to clean up and keep it looking nice if that's a big deal. alot of people just don't realize that driving 50 mph down a gravel road kicks so much garvel into the wheel wells that it's like a a sandblaster. check out a 1 year old truck that's been driven on even a little gravel and you'll see how much paint is missing. in my detailing, i use a good coat of black paint in the wheel wells to keep them clean looking and for a special look i have found really comes out when you do it.

 

i have used bedliner on several underbodies of vehicles i have restored and it always come out right. it really keeps the crud off the truck. for the most part, mud and debris will just fall off or hose right off. an undercoat will hold some of the dirt and dust and requires a pretty good amount of cleaning to keep it clean. i feel that all the dust, dirt and debris is a big rust hazard even if there is undercoat on the metal. i'd rather know that a drive in the rain takes care of any crud that might be on there.

 

i will tell you that my entire truck is covered in bedliner. not just the bottom, the whole truck. it holds up great to anything that i throw at. ;)

[bmyohn]

I just got my Comanche undercoated at Ziebarts with their sound deadining application. For $180 and lifetime warranty against the product chipping off its not a bad deal. It's plenty thick and should last a long time. I am contemplating doing it to my DD as well (2001 Dodge Rams 2500 CTD), just to see if any noise is actually reduced, the MJ isnt running so i can't really tell the benefits from that. But for a rust preventer, when applied correcetly can work wonders.