rust in the seams

[cajunz]

Hey guys, I'm currently stripping all the undercoating off of the undercarriage of my '78 and I'm finding areas of rust in the seams. Whats the best way to get at this corrosion. I'm digging out as much of the seam filler material as I can. I want to get to every last area of rust before I POR-15 and re-undercoat the the bottom of the car. All suggestions appreciated.

Brent

[oldhemi]

Sandblast with a real fine grit? Mild acid wash? Doesn't POR have a "Marine Wash" that you apply 1st?

Good question that will be interesting to see what other folks have done!

[EScanlon]

The "Marine Wash" you are referring to is called Marine Clean and it is used as a De-greaser. Sandblasting with a fine grit won't reach between the joined pieces of sheet metal far enough to really make a huge difference. By the time you pumped up the pressure you'd be warping the sheet metal or pulverizing your media.

The acid wash that is used in the POR preparation method will seep in between the metal pieces as far as liquid can, but since it is a phosphoric acid it will affect the metal and help rust-proof it. It's called Metal Ready.

There are other metal prep solutions you could use, but since you have to use the Metal Readyto prepare for POR, it goes hand in hand.

FWIW

E

[geezer]

Short of drilling out the spotwelds to totally access the rust that is harboured inbetween, in most cases you will not get it all. After tackling it the best you can, using all the methods known to man, you can then encapsulate it, in order to keep air & moisture from contacting it, thus preventing the rust from spreading. If there is a better way, I would like to know about it too.

[ajmcforester]

Short of drilling out the spotwelds to totally access the rust that is harboured inbetween, in most cases you will not get it all. After tackling it the best you can, using all the methods known to man, you can then encapsulate it, in order to keep air & moisture from contacting it, thus preventing the rust from spreading. If there is a better way, I would like to know about it too.

The only thing I know better is to start with no rusted seams. The best advice it scrape clean and encapsulate. I know Eastwood Company has a so called safe metal rust removing liquid, you could give that a try, I've never used it. Remember POR15 bonds well to rust you just don't want it to be thick rusted areas.

PS get some tyvec suits your going to need it with POR15, it don't come off the skin well.

[cajunz]

thanks for all the advice everyone. I was kind of thinking along the same lines with using the acid wash to get into the seams. I may try opening a few of the areas as best I can to really get at the rust. I'll keep you updated to let you know how the process goes.

Brent

[jmortensen]

Spray oil in the frame rails. That's what they do in Canada. I did a little research in trying to find out what oil they use, and wasn't able to come up with an exact answer, but I did figure out that it had some fish oil in it. http://www.krown.com/#default

I also found some people in the US who had done this with used motor oil and WD-40. My plan was to get a gallon of Kroil and use that, because hey, it's "the oil that creeps". I think just about any oil works though.

[ZCurves]

Here is what I used. It is like Cosmoline (Parifin and Motor Oil).

http://www.eastwood.com/ew-heavy-duty-anti-rust-32oz.html

Sprayed this in the rails and any other cavity I could find (Seriously) -including the doglegs (accessed by seatbelt assy bolt hole) -AFTER I applied Phosphoric Acid. It has been almost 10 years and everything is good so far!

[ajmcforester]

I've used Gibbs and Boesheild T-9. The boesheild is only good for hidden areas since it is yellowish, but gibbs is clear it also keeps the cast aluminum looking new

[cajunz]

Again, thanks for all the input. Does the Cosmoline or Kroil have an odor thats gonna overpower my lovely exhaust fumes?

Brent

[ajmcforester]

Try replacing the worn out rubber to get rid of the exhaust fumes, and fix any leaks. Of course the blue pine tree on the mirror might work.