Vehicle body rust--high tech remedies?

[ThosL]

I have some significant body rust in the wheel wells of my Subaru, the metal is still intact, but I was wondering if there is any treatment to staunch the rust process to prevent the rust from eating through or the metal decay to develop holes?  Is there a paint or primer product you can spray on that will solidify the weakened body and prevent it from breaking down?

[mikaleda]

POR-15 it seals and encapsulates rust, I found out about it when I was working at the service center and we were restoring old Pontiacs.

 

Its expensive about $45 a quart or $180 a gallon, but it works good.

[mikaleda]

http://www.por15.com

 

Here is a link to their site check it out

[subarubrat]

POR is great stuff but you need to get the entire system and follow through all the steps. Just painting it with POR 15 paint will only mask it.

 

The full steps are:

 

Remove as much rust as possible

Marine clean and rinse

Metal Ready

Apply POR 15

Top coat

[AdventureSubaru]

X2 on the POR15. it's good stuff..

 

I've had success with the Rustoleum rust converter. Home Depot and others carry it. my process was to grind or sand the rusted area and get the lifted/bubbled paint off, more is better. Then apply a coat of rust converter, and several coats of paint on top.

[mikaleda]

Interesting it looks like they don't make rust converter anymore, but they make rust refomer

http://www.amazon.com/Rust-Oleum-215215-Reformer-10-25-Ounce-Spray-Color/dp/B001DEL6J6

 

Looks like the same thing, I might try this out myself, be convenient for small projects.

[CNY_Dave]

The rust converter that is essentially tannic acid slows the rust down a bit, even if you just knock off the loose stuff and dab/spray it on.

 

Good for a few months at a shot.

[mikec03]

 

Good for a few months

 

LOL.  Painting it would also be good for a few months!  The POR may work but you would have to incapsulate the rust on the inside of the fender too.  Obviously, one has to cut a big hole to get to the inside.  The real secret especially for the fender rust, is to cut all the rusted metal out.  Get down to good metal.  Then fiberglas or weld metal over the hole,etc     

[mikaleda]

 

LOL. Painting it would also be good for a few months! The POR may work but you would have to incapsulate the rust on the inside of the fender too. Obviously, one has to cut a big hole to get to the inside. The real secret especially for the fender rust, is to cut all the rusted metal out. Get down to good metal. Then fiberglas or weld metal over the hole,etc

It depends how soon you catch it, obviously if there is a hole rusted through then no por15 wouldn't be a good idea, but if you catch it before it rusts through and you prep it properly the por-15 will stop the rust and strengthen the metal once it hardens. It does work I've seen it do exactly what it says it does.

[Fairtax4me]

The problem with rust on the wheel wells is it comes from the INSIDE. Paint the outside all you want, it'll still rust. Have to cut out ALL of the rusty material and rebuild the panel out of metal or fiberglass and body filler. 

 

Part of the problem with the second gen legacy wheel well rot comes from the black body trim they put along the seam in the wheel arch. The trim traps water and dirt/salt in the seam, eventually the sealer applied to the seam degrades and the water is wicked in between the two panels that join there. Then the rust starts to work its devious magic inside where you can't see it until its too late. 

[ThosL]

Thanks for the feedback on this issue; it looks like the best product is the POR15.  I don't need a quart, though.  I will look over the remedies again to see if there is any basic remedy which makes sense for me.

[keith3267]

You need to get off as much rust as you can through a wire brush or sanding or a nylon flapper wheel on a grinder or high speed drill.  The nylon flapper wheel is the best way.  The clean and degrease.  As soon as you rinse the degreaser off, you need to apply a solution that contains about 50% phosphoric acid, which the por 15 metal prep is. 

 

http://qr.absolutecoatings.com/QR-assets/downloads/POR15/POR-15_TD-MetalPrep.pdf

 

Phosphoric acid is available from other sources and is probably less expensive than the por15, but even the por15 isn't that much in the scheme of things here.  If you have any rust remaining, it will take the phosphoric acid about a half hour to work, with rust free bare metal, it works in about 5 minutes or so.  Rinse it off and then dry it as fast as you can.  A hair drier or heat gun would come in handy here but even compressed air would help.

 

As soon as it dries, it needs to be coated as the iron phosphate coating the phosphoric acid forms will crack as it dries.  There is a micro sealer that is available to industrial users for this, but I don't think it is available to consumers in small quantities.  My preference for coating would be a Zinc Chromate primer.  I think you can still get one at NAPA.  You can get it at Amazon.

 

http://www.amazon.com/Moeller-Green-Chromate-Primer-Outboard/dp/B000N8LR24

 

Or you can use the por15 coating if you want.  I believe it is a good product as well, I just have a lot of experience with the zinc chromate on aluminum and magnesium in a salt water environment.

 

BTW, you never win against rust, you can only prolong the battle but in the end, rust will prevail.  But you can prolong the battle for a very long time if you are willing to do the work.

 

Edit, I don't think the zinc chromate is a sealer and it is old school.  The por15 is new school and may contain a sealer.  I would still use the zinc chromate over the por15 though as the zinc forms a sacrificial barrier to rust.  The metal underneath will not rust as long as there is some zinc to corrode first.

Edited January 15, 2016 by keith3267

[sirtokesalot]

i might back into this tree myself when winter is over if it doesn't collapse my then.  i think it should be fine there's plent of metal left on mine but there's also very large holes. fiberglass is going to be my tool for repair.