So this winter I've got a bunch of plans while the car is in the garage. One of the bigger ones is to undercoat the box. im familiar with the basic idea but wanted some additional input. There are a few places on the under body that are begining to show signs of surface rust. I plan on sanding them down and painting over them w/ that stuff that turns rust to a primed surface. i then wanna hit those spots, the wheel wells, and the rest of the underbody w/ an undercoating. I've heard that undercoating can actually make rust worse if done wrong, any truth in this? I plan on cleaning off all the surfaces of dirt and stuff so nothing get pinned betweeen the undercoating and metal. any other tips would be greatly appreciated. and, does anyone know where i can find this stuff in a traditional(for brush) paint can. Since i dont have a lift using rattle cans would be a total pain.

I did find these guys

http://www.proformproducts.com/en/pr.../detail/?id=26



And maybe this stuff?
http://www.autozone.com/R,NONAPP1163...ductDetail.htm

 

Yes undercoat can cause rust if it is applied over a rusty untreated surface or if it seals necessary body drain holes. Treat any surface rust with POR-15 before undercoating and be sure not to plug up any drains (there are some in the rocker panel flanges) and you should be fine.

 

funny ted, i was actually praying u would be the one to answer

 

so if i use somthin like what i posted above, can i just brush it on?

 

you know these cars have underbody coatings right ?

 

yes and no, not really through. and like i said, im also working on some areas that are already giving me problems. plus, im puttin it on thick for some sound deadening benefits

 

well the masin thing is doing it in the correct temperature . the product will specify what temps to apply in. follow that

 

didnt even think about that, under 50 its probably not too fun

 

no probably not. gonna take way too long to set I would imagine

 

That stuff should be brushable altho it is designed to be srayed from a shutz gun. I would recommend some Wurth rubberized undercoating (red cans) in spray cans. These cans have a very nice nozzle and can (used to be anyway) used with a tube like you use on carb cleaner for even more controlled application. Very durable stuff. I would not apply any undercoating under about 60 degrees.

 

And just to repeat the original answer: if you do not *totally* neutralize (or grind down to bare metal) all of the pre-exising rust, it will just keep spreading (like cancer) under the undercoat.

 

the dealer offered to do undercoating when i got mine, i said "no" only because i know its more $ threw them.

i do plan on getting it done. who is a go compainy to take it to. you know like Zbart
this is a good thread.

 

Indeed!! You must also be sure the areas to be undercoating are totally clean and devoid of any corrosives (salt residue etc) to avoid trapping contaminants under the undercoat with the same cancerous results.

 

this is off topic, yet still on topic.

werent some of our cars already sprayed with undercoating? depending on where you lived, of course.

my box has a weird rubbery substance in the wheel wells and such, and im relatively sure its underbody sealent or something..

 

Yes there are some areas that have a sealent/sound deadner/undercoating on them. One thing I have found is that some undercoats seem to soften this layer and it stays sticky forever after so test a small spot before comitting to covering this "stuff" with your fav undercoat.

 

I still laugh thinking back at all the "Zeibart" rust proofed vehicles that were just as rusted out as the ones without the stickers.
Unless you did this when it first came out the factory I feel it's too late. This stuff will prolly do more harm over time than just keeping the underbody clean of salt. Just keep the rusted areas touched up and inspect the underbody regularly and let the moisture drain away instead of trapping it where it cause a breeding ground for more rust. Not to mention the awful smell of the RP stuff.
BTW, didn't you say you were storing your box in a bubble over the winter months? If so why worry about rust. Just wash the underbody good. Make sure it's fully dry then store it away.
Sound deadening goes on the inside for the best results.

 

1) Im touching up n coating areas that are already bad

2)The drains only get plugged if u dont pay attention

3)My car already has alot of interior deadening and I wanted to try somthin new

 

started the proj today, and its goin pretty well. i did decide to do spray cans which are a bit of a pain since there isnt too much room to get under the car. but, all in all it'll work. and just a tip-

RUBBERIZED UNDERCOATING TASTES HORRIBLE!

some dripped into my mouth during all the fun then i jumped and headbutted the cat converter...fun times

 

When you have bare metal the first step is to coat it with a self etching primer. This "eats" in the metal slowing the rust down. After that cures, then you can spray undercoat over that which will give you some protection, but its also deadens sounds. *Tip* if you can find a wire wheel or a tool called the "CRUD THUG" made by Snap On, it works wonders on taking off undercoating.

 

nice to know