Cavity Wax

B

Bob Hollinshead

On restorations, when you are done with the paintwork on the vehicle's underside or similar areas it's a good idea as a last step to spray cavity wax into all the boxed areas and seams. You can spend all the time in the world removing corrosion from the exterior areas and still have corrosion in boxed areas and seams that eventually will crawl out to haunt you if steps aren't taken to cut off the supply of oxygen. I've taken apart cars and parts that were dipped and it is the same situation especially the tight seams. Transtar makes a good coating, 3M offers rustfighter which is ok, Amsoil MP-HD is also decent, and there are others including Rustfre and cosmoline. I usually tape up the seams to keep most of the product where it needs to be. Rotate the car and let gravity fill up voids, rotate it 180* and repeat, and rotate upright and repeat. On projects that aren't going to be judged you can seal up the seams with seamsealer prior to paint and avoid the need to mask them. Wipe off the majority of any run off as you go, let the tape set overnight while the wax sets up, then final clean any excess with solvent based W&G remover or mineral spirits. The Transtar Amber Coat is good stuff and they offer a cheap kit with a small diameter 360* spray wand that gets into areas where my Walcom setup won't go. If the car isn't on a rotissery you can still jack up the sides enough to get enough angle for gravity to help move the product where it needs to go. Multiple passes with a few hours between application is best.
 
Good tip Bob, I always spray black epoxy through a 360' sem wand. Doors and hoods and trunks I'll pour it and tip it around.
 
I like epoxy in these areas too but the cavity wax is extra insurance
 
TransStar makes decent stuff. Is that like a cosmoline wax spray? I did rust proofing at a dealer years ago and sprayed the yellow colored waxy spray in the doors, same stuff?
 
Bob turned me on to the Transtar a few years back. It has never reflowed for me. It does smell for a month or so. I use it around the farm a good bit too. I put it on any hydraulic cylinders that sit out over winter. In the spring I spray brake clean on a rag and wipe it off. It seems to work pretty well.
 
TransStar does have a nice Olive (green colored) epoxy that matches very well to factory Ecoat. I've used it alot when our jobber carried it.
 
My 1986 1991 1993 Caddy Coupe's say bless Bob for starting this thread. I'm a paraplegic & drive these cars since accident in 1989 cause they're wheelchair friendly.
Every one of these cars & others i've looked at rot where windshield posts meet above top door hinge.
I'm not chopping posts out, one grew a weep hole for water to escape lol.
I considered filling it with epoxy but after finding this thread, i'm so glad i held off.
Which of all mentioned would you pro's roll dice with to neutralize & seal?


Here's a few i found searching for Transtar.
http://www.noxudolusa.com/products/rust-protection-products/
http://www.eastwood.com/internal-frame-coating-w-spray-nozzle.html

ps- i layed down 3 coats of UVC on the 1993 hood yesterday, needs cut/buff. 1991 3 weeks ago cut/buffed & "wow" is always peoples 1st words heh. Beautiful stuff UVC is.
 
Brad, are you putting the epoxy in an undercoat gun with wand,or does SEM make some other sort of sprayer..

Thanks, Chris
 
Bob Hollinshead;n79359 said:
I like epoxy in these areas too but the cavity wax is extra insurance
Click to expand...
Bob
What would you recommend to kill and protect inside a door where rust is coming out from the seam on the door skin. It is almost breaking through the paint. We will be pulling the door panels to inspect but would like an idea of what to try while it is apart. It is a 2004 Dodge PU. I have an untested KBS Coatings sprayer for those hidden spots but would rather start by testing products on what I can actually see the results of.
Anyone else with ideas or experience or other known problem areas please weigh in.

Thanks
FarmBoy

"I ain't smart enough to be scared"
 
I'm not sure there really is a way to "kill" rust and truly stop it without grinding it out. I use POR15 from time to time, but it's really just a big time delayer. Expecially the bottoms of doors in pinch welds. You may cover and coat one side, but it's just going to work its way through the other side.
 
There are electronic devices to help slow down rust. Some large equipment vehicles use them. Don't personally have any experience with em.
 
FarmBoy;n81166 said:
Bob
What would you recommend to kill and protect inside a door where rust is coming out from the seam on the door skin. It is almost breaking through the paint. We will be pulling the door panels to inspect but would like an idea of what to try while it is apart. It is a 2004 Dodge PU. I have an untested KBS Coatings sprayer for those hidden spots but would rather start by testing products on what I can actually see the results of.
Anyone else with ideas or experience or other known problem areas please weigh in.

Thanks
FarmBoy

"I ain't smart enough to be scared"
Click to expand...

Rust on door seams is a common problem in this area and we all know the only way to remove the rust within the seam is to open the seam up-remove the skin... The severity of rust you describe where the rust is just starting to creep out of the seam is the stage where most people get concerned and want to do something about it... I have had really good luck just blasting the exterior or the seam to remove as much rust as I can, apply 2-3 coats of epoxy primer followed by urethane seam sealer and paint. I then tape the drain holes shut and spray the inside well with Transtar Amber Coat. Peal the tape off a day or two later and open up the drain holes. My theory on this is if I can't clean all the rust out of the seam I'll do my best at coating the exterior and interior to seal it off from oxygen/water/road salt... so the rust stops growing. The transtar does flow well but the seams that are tight are a problem for anything-even panels that have been dipped still have seams full of rust when I open them up. The sad part of all this is it's a manufacturing problem- I can put a door together and the seams will hold up for 30+ years why can't the oem's?
 
FarmBoy;n81166 said:
Bob
What would you recommend to kill and protect inside a door where rust is coming out from the seam on the door skin. It is almost breaking through the paint. We will be pulling the door panels to inspect but would like an idea of what to try while it is apart. It is a 2004 Dodge PU. I have an untested KBS Coatings sprayer for those hidden spots but would rather start by testing products on what I can actually see the results of.
Anyone else with ideas or experience or other known problem areas please weigh in.

Thanks
FarmBoy

"I ain't smart enough to be scared"
Click to expand...

With vertical seams I take the doors off so I can rotate them and spray the inside so the coating flows downward into the seam. The picture sure looks like it shows rust growing from the outside inward. No seamsealer on that seam from the factory is a big mistake IMO.
 
One of the worst I've seen is some of the ford trucks in the early 90's, they had a seam on the bottom of the door that wasn't closed-it actually flared out at the top to catch all the road salt it could... they didn't survive more than a couple of winters before the whole lower seam was turned into rust.
 
one reason repairs on restorations may last longer is that they are not returned to the same type of service in the same elements.

I cant see any product that would do as well as epoxy sprayed into such areas. I have not seen rust creeping back from areas described, unless they have been returned to the harsh salty and wet environments they come from. I use epoxy, and spray well into bottoms of doors and other problematic areas and soak it well. One question, would reducing the epoxy gain any significant gains in a lower viscosity to get deeper into cracks and crevices?
 
A general question first - what would adhere better to a surface that can't be reached to prep properly - epoxy or cavity wax? I have no experience with either but I'm sure it will find me eventually.
Secondly, I can't see disassembling this door to properly clean and prep the surface for epoxy or wax but I love the remove and tip idea to spread the product over a larger area so that's the reason for the first question. FYI - I'm not a body/ paint guy so everything I have done so far is on my dime because I like helping family and friends for the practice so no one is going to come back and complain - I hope!
 
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