Hey guys,
I'm thinking of how I will be patching up the rockers etc. on my olds and I wanted to find out what others have done.

If you are welding a patch in a place where you can't easily paint over the weld (like on a rocker panel) how do you treat the steel and prevent rust at the weld?

I googled the weld thru zinc primers, but there are a lot of mixed opinions on how good that is. Eastwood seems to have a bunch of products for rust, including "heavy duty anti rust" for inside frame rails.

What do you guys think? Any experiences?

 

Short of an e-coat dip of the entire body (which is how the factory did it), weld-through primer is the best you can do. I'm not convinced that spraying something into cavities like the rocker after welding will have much effect. You can get weld-through primer in either zinc or copper.

 

I use weld through primer or cold galvanize paint. But a better choice has to be drilling a hole for access and using something like that Eastwood inside the frame rail hose http://www.eastwood.com/internal-fra...nozzle-qt.html. Paint up the edge of the hole and plug it like the rustproofing guys do.

 

Thanks for the link.

From what I've read on misc. forums online, there are mixed reviews of the zinc/copper weld through primer. Some people swear by it, and some refuse to use it. Some people note that the primer would add contaminants to the weld. It seems that the only reason it is called weld-thru primer is because it conducts electricity and doesn't burn up as much as something like epoxy primer.

The Eastwood internal frame coating products look good for these hidden areas. I am leaning towards that. When I'm done welding areas like the rockers I can drill a hole in a good location for applying a coating. I'd make sure the hole I drill will be sized for a rubber plug to put in when all is done.

 

My 67 has a factory hole in the rocker in the rear wheel well with a plug, and one inside the rocker also at the rear it has a flap to keep things out but also let water drain out. Either one of these could be used for the Eastwood coating.

 

In collision repair they have a wax that the spray into the area that you can't reach with paint,
I used it on my 65 at the bottom of the doors and wheel well area

Just a thought

 

thats funny.cuz volkswagen uses wax for undercoating on their cars!

 

The wax is more for frame rails. Now a nice trick I learned is clean out an old wd 40 spray button and clean the straw and use it on the zinc rich primer can to blast it where it is needed . you will waste more but in limted access areas it will push it further than the typical paint button on the spray cans. You can also buy the quarts of undercoating with the gun and the long reach straw. You will be amazed how well regular undercoating works over welds. Ask me how I know this lol . I did this on my 72 in some areas and 7 years later no rust on the welds.

 

We were always taught to protect the back of our welds.
1.Weld through primer yes
2.Some type of rust proofing would be sprayed, even if we had to drill a hole to gain assess.
This has been standard practice since the early 80's
One body man I new, liked to use the rocker guard gun to spray rust inhibitor.
Make sure all panel drains are clear after under coating/the application of rust inhibitor.

 

One thing to add (and NOT because I know anything about it) is that if you are starting with the rocker off of the car (and the space behind it open), you can drill the hole, prepare the hose or straw, and generally do a trial run and get everything set up before you put it together, so that you know that when you are spraying blindly into the hole(s), you are actually putting coating on the welds you want to coat.

- Eric

 

This is one of the things we use @ shop-
Fluid Film "pro model" on lower page. Obtained from local NAPA store. I've made numerous variations out of stuff laying around but this gives you good utility in a turn key package.

http://www.kellsportproducts.com/undercoatingguns.html

Fill it w/ thinned POR-15 & flood the rockers after install through whatever holes are there or made under scuff plates, wheel well, cowl, striker holes, etc. make sure you put plastic or paper down because you want it running out of every seam & drain hole. Jack car up from back to make sure it runs all the way front, let sit a minute or two & then jack front. Check drain holes as paint hardens to make sure they are clear. As stated above, be sure to touch up any holes you drill w/ POR so edges don't rust.

THOROUGHLY clean sprayer & do the same w/ wax rustproofing a day or two later. You could use Fluid Film or some specific rustproofing product.

Rubber Seal makes aerosol cans & small, compatible flexible wands that are convenient too.

 

Fluid Film is a great product! I use it on all of my vehicles.