Technical Leaving car in epoxy primer

It's all a compromise,
Some guys just do not have the time to take a paint job from bare metal to finish paint and hit all the cure windows.

 

How does it block sand?

 

Epoxy in general is a love/hate gig. "E-coat" as offered by some strippers is really a toss of the dice. I spent more time than I have in over 40 years of finishing sanding and edging and prep work so I'd get awesome adhesion on the latest job. It was E-coat. With no exaggeration it turned out to be the worst adhesion ever and pealed away from body reveals like it was teflon. Yes it was clean, yes every possible surface sanded, yes with enough tooth by using nothing finer than 150, yes it was dry sanded. This process took days to complete. No contamination, none of the 'wrong' solvents used. Never again. I was told "...well you have to sand it all to bare metal so..." and that's the most ignorant reply ever. Why the **** would a guy buy a body with a $1,000 option of E-coat so he has to sand it all to bare metal?

Bottom line, put on your own, study the tech sheets, allow for temp and humidity changes that effect it's recoat window. Hot=sooner, cold=maybe never, too humid=wait for a better day. Again if it's all you want just shoot and forget it. If it's meant to protect don't use too much. And on sanding, I never met an epoxy that didn't ball up on your sandpaper. Wet, dry, fine, co****, no matter. Just the nature of the product I reckon. Your results may vary, void where...

 

Highlander, I had never encountered an epoxy that didn't ball up when sanding either until I tried the PPG CRE221. I haven't used it enough yet though to have a track record of how it will hold up. I'm starting out just testing mostly on small parts and removable panels before I try it on anything of significance. High end restoration work like you do may not be the place for it. I used to swear by DP back before it was lead free. I have had issues in some instances where it would crack in a tight inside corner. But, that may have been my fault by putting it on too heavy, or pushing the dry time and putting on the primer over it too soon and/or too heavy. I did do a puck test of equal amounts of the activated and reduced CRE and activated and reduced DP. The DP puck shrank considerably more than the CRE. To me, that says a lot.

 

I haven't painted a car in 30- or 40-years and back then, I used Acrylic lacquer. About 6-months ago, I I epoxy primered my '36 coupe with PPG DP40 LF. I had previously sandblasted & cleaned the sheet metal with Prepsol. I sprayed the Epoxy and it laid down great. a few days later, and in the "window"), I top coated the bottom of the floor pan & firewall with PPG top coat and clear. It turned out great and still is beautiful with no signs of any adhesion problems. Due to a back injury, I haven't been able to work on it for the last couple of months, but the primered parts show no signs of any rust and I'm expecting it to last until I can work again.

1479595465828 by TagMan, on Flickr

 

Good stuff guys. I use Shop-Line PPG epoxy. It's not lead-free and less "filtered" for other trace metals according to my rep. It likes being used as a sealer and prevents excess solvent penetration. I don't have anything that's suited for long term epoxy time at the moment. I'm also not one of those who worry about what "might" happen as a part or body are under repair/construction. Surface rust can be cleaned and etched easily and nothing sits outdoors.

 

its more of a sealer like the old DP
its a 1:1
its sands better than most epoxys I have used. I sprayed some Harley parts with it this week, wet sanded with 400/600.
its is harder than a urethane, but sanded well for an epoxy.
there is a filler version of it that I have not used yet, but is not available in black

this epoxy lays down much smother than most of the newer voc compliant ones I have sprayed

 

Try the CRE, if you don't like it I'll buy it from you.
You can block and fill and block pretty good size frame / suspension parts pits with it.


These two bikes collided in the trailer when they fell over last weekend.
I painted the raspberry one in back April. Started off with CRE, couple rounds of polyester on the tank then 2k primer, then CRE for a sealer and straight to color. I'd say that's pretty good adhesion because the paint didn't even break.

I did not paint The yellow one, well it used to be burnt copper and the original color is clearly visible, that yellow paint job,,, if you look at it wrong it chips off.