coating/re-doing underbody??
 

Well i was searching through the forums and found that 1st gens are known for rusting through the support bracket and through the bins. I checked out my car and sadly to say i have it too. Is there anything to worry about? is it ok to drive? im going to rip up the bins tommaorw and make sure its just rusting though the bins and no where else. The rest of the underbody is decent on my car. What can i do or spray on the underbody to keep rust away after i fix the bins. I wanna spray the whole underbody

im not sure exactly what it was but my dad and i used some stuff on his old jeep. it was this black spray shit for like a windex bottle, and it prevents rust and also soundproofs. i will find out what it was later and let you know. it was pretty cheap too. never had anymore problems with rust on that one.

any1 else?

Check out the 2nd gen forum. One of the moderator's Aaron Cake has a thred on his rx7 on how he applied this shit POR-15. With pics the process is not for the faint haerted.

If you do your prep work properly, the Duplicolor truck bed liner works pretty well. Otherwise there is a rubberized undercoating in a spray can. There is no point in adding any coating unless the rust is removed and converted, then sealed with something like Por-15, a self-ecthing primer or an epoxy coat.

Sealing over a poorly prepped surface will simply trap moisture and allow the rust to work faster.

well i mean the car is getting old, so i wanted something to prevent this stuff

can POR-15 be used under primer?

POR-15 is great and it falls under the same lines that each and every other person here has suggested and they are completely incorrect for this application.

Each of the items suggested are cover ups and preventions NOT neutralizers. These Items should ONLY be applied on a prepped surface with no current rust or the rust will be trapped in forever destroying the rest of your car.

I am a pessimist about this I feel the only way is to grind the metal all down and cutout the bad spots and reweld new metal in. You have to get to good metal or the rust will just set back in. Other body men I know swear by rust neutralizers found at any parts stores. I do not feel this does a good enough job to ensure rust not coming back. If you miss any spot between metals it can come back. This is why I do not prefer rust treatments for metal that has been rusted through or is plied.

Maybe you should read more carefully, not all of the posts are wrong. I stated a properly prepared surface, that would include, sandblasting, grinding, or replacement, which ever is most appropriate. The rust converters do work well, but they do not prevent rust. If left exposed, many of them will allow the rust to return quickly. They should only be used when the last tiny bits of rust cannot be removed by mechanical means, and the part in question is structurally whole and intact.

If the metal is rusted through, replacement is the only option to maintain the structural integrity. Mazda's better idea of using 3 plys on the rear wheel wells was an absolute failure in terms of longevity, but concidering economics and planned obsolesence, they held up long enough.

That is absolutely wrong regarding POR-15. POR-15 (Paint On Rust) is designed to be painted DIRECTLY over rusted surfaces after excess flaky rust has been removed. In fact if you apply POR-15 to virgin metal there are several additional prep steps required. A prep called MetalReady (basically phosphoric acid with a zinc ion) is used to first temporarily stop existing rust and leave a light zinc coating. Then POR-15 is applied after the surface has COMPLETELY DRIED.

The way POR-15 works is very, very simple. It just forms an impenetrable coating that denies metal the chance to contact moisture. It's a simple as that. It cures very tough, very slick and without pores so there is no way for moisture to enter. Regular paint dries as the solvent evaporates which leave tiny pores. POR-15 dries by absorbing moisture (even "sucking" it out of existing rust) as part of it's curing process and thus is non-porous.

I read there site but I got you had to remove the exsisting rust first. "You said that was only stating the flaking matter of rust and big gaps" Well that makes it alot easier to use.


Moister is two parted if you get moister on the other side of the metal it would still rust it. So if you dont remove the rust whats to prevent it from rusting from another entrance?

No POR should be under any primer, if primer is used at all. www.por15.com

I have used it several cars, they even have a solution to fill holes which works well and lasts well also. I had pin holes in a pick up bed, filled, painted and used for years without any problems.

I've used POR-15 on eeverything from cars to machinery thats outside all the time. It works very well and paints over (scuff it up 1st - it flows out very smooth) Only bad thing is that it does not stand up to UV fir very long at all. Have a steel toolbox top thats was painted aboput 7 years ago (clear POR) in my cellar and it has lasted well with no UV exposure (kind of an experiment).
I'd recommend it.

You need to remove any multi-layer or flaking rust. Surface rust and such can stay as that is what the paint is designed to bite onto.

If it has rusted through then you will of course need to treat both sides. For the most part this is not a huge deal as you can get creative in application (brush on a stick, piece of cloth on a wire, sprayer, etc.) Ideally of course you want to treat both sides but if it's in a spot of limited access then just treating the external surface makes a huge difference anyway.

They use to sell some stuff called naval jelly it was good for treating the rust turned it into some hard ass material . But i would go with the sandblasting or using a wire grinding wheel to remove all the rust then treat it with the POR 15 i think thats what the speedshops recomend too. then just get someone to paint it i had cleaned my wheel wells really good and had my boy shoot it with some DBU paint & clearcoat to add extra strenght so it doesnt pit so easily from the rocks and stuff your tires toss in there. Cause if you live in NYC that dam rocksalt kills your car quickly once it finds the rust to thrive on i lost my 2nd fb which i had painted so pretty finally had it lookin how i wanted it & 3 yrs later i noticed the rust ate through the bins you could touch the tire from inside and the underbody had some bad parts too. so i have another and now i have to start from scratch again. So invest on what you must but paint rubberize treat sandblast or whatever you can afford b4 you end up like i did. :wallbash: :pat: :offtopic: