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DP Epoxy Over Lead Joints OK?

Started by 7E-Bodies, March 11, 2023, 02:37:52 PM

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7E-Bodies

I'm thinking the answer to my question is "yes". I'm following the "How to Paint a Show Car" write up by @Cuda Cody to the letter and am hoping he can chime in here. I'm not seeing anything on the PPG spec sheets that mentions lead as a bonding surface, although it mentions metal and lead is a metal. I plan on prepping the leaded areas in the same fashion as the write up depicts for the body sheet metal. My instincts say it's a go, but I want to be fully sure that nothing special needs done over lead other than the 150 grit, red scotchbrite applied SX579 (1:2 water mix) and SX520 (straight) as the article indicates. I'll wait until I hear.
1970 Challenger R/T Numbers Matching 440 Auto in F8 Quad Green

Mr Cuda

I believe the answer to be yes. That's what I'd do.
I actually have problems with the idea of dx 579 on areas where fluid can penetrate a crack,pinhole or joint.  I might just solvent clean and prime.
There is a school of thought to use an etch primer over lead, but the problem is, you are not supposed to apply epoxy over etch. Plus, the etch primer these days is ineffective,  with no real acid activator.
In the days before ppg had the dp series,  (yes i did bodywork back then), the etch and lacquer primer was all we had.



tparker

Just for clarification, is it the original lead? I re did my roof and it was a lead free material. Probably doesn't make a difference, but maybe. I didn't do anything special but I didn't use PPG products. It seems ok but its only been a couple years. We'll see in a few more. LOL.


7E-Bodies

1970 Challenger R/T Numbers Matching 440 Auto in F8 Quad Green

jimynick

Don't forget to wash the leaded area with thinners to remove oils and the beeswax and then wash the lead with a slurry of baking soda to prevent bleed through down the road, before getting into priming.  :cheers:
In the immortal words of Jimmy Scott- "pace yourself!"

7E-Bodies

1970 Challenger R/T Numbers Matching 440 Auto in F8 Quad Green

7E-Bodies

Well, I just got off the phone with PPG as an added safety measure. They said bonding with lead using DP40 is fine as long as the area leaded is meticulously cleansed and neutralized (I use baking soda and water to neutralize after lead work to kill the tinning acids) and of course wax/degreaser to eliminate any tallow traces from the paddles used to apply the lead. They said after all of that, use a 1:1:1 mix of denatured or isopropyl alcohol (90% minimum strength), ammonia, and water and to keep it in the lead area and not let it run all over other bare metal surfaces, then rinse with cool water, dry and apply epoxy.
Anything additional, I'm all ears...
1970 Challenger R/T Numbers Matching 440 Auto in F8 Quad Green