Epoxy Primer Issues

[my928s4]

Been lurking for a while but here is my first post.

First note this is my first project that I have done any bodywork so lots of newbie mistakes but things were actually progressing quite well until today.

I did my filler work then two coats of MP171 Epoxy primer followed by MP282 2K primer. Taken lots of work to get everything nice and smooth and then today I see a crack hmmmm, pick at it and the primer starts coming off.

Looks like the 2nd coat of Epoxy did not bond to the 1st, I had printed of the manufacture spec sheet and abided by the rules. Leave at least 15min in pot and I waited 15-20 mins before the 2nd coat. 2K was applied the next day.

Luckily I have been doing one fender at a time (only completed 2) so I am hoping issue is isolated but until I know what I did wrong that is just a hope.

So what did I do wrong?? Advice much appreciated.

Thanks

Chris

[MARTINSR]

Your confusing me a little here, did the EPOXY peel off it's self (first and second coat) or did the urethane peel off the epoxy?


Brian

[my928s4]

Your confusing me a little here, did the EPOXY peel off it's self (first and second coat) or did the urethane peel off the epoxy?
Brian

It looks like the Epoxy peeled off itself, luckily I used white Epoxy and Grey 2K Primer.

Chris

[Len]

It looks like the Epoxy peeled off itself, luckily I used white Epoxy and Grey 2K Primer.

Chris

Wow, I don't have an answer for that one. You're saying that you applied a second coat of epoxy primer on top of the first coat of epoxy, within the recoat window and the first peeled off the second after the 2K was applied.

I'd recommend that you prep the next panel and try again and only use one coat of epoxy to see what happens.

Another recommendation would be to contact the primer manufacturer's technical support department to see if they have any suggestions.

[Steve g]

Been lurking for a while but here is my first post.

First note this is my first project that I have done any bodywork so lots of newbie mistakes but things were actually progressing quite well until today.

I did my filler work then two coats of MP171 Epoxy primer followed by MP282 2K primer. Taken lots of work to get everything nice and smooth and then today I see a crack hmmmm, pick at it and the primer starts coming off.

Looks like the 2nd coat of Epoxy did not bond to the 1st, I had printed of the manufacture spec sheet and abided by the rules. Leave at least 15min in pot and I waited 15-20 mins before the 2nd coat. 2K was applied the next day.

Luckily I have been doing one fender at a time (only completed 2) so I am hoping issue is isolated but until I know what I did wrong that is just a hope.

So what did I do wrong?? Advice much appreciated.

Thanks

Chris
I use those same products in the same fashion as you and have never had that problem. The recoat window would be my first question. I generally only use one coat of epoxy, but as long as the second was applied within the recoat window (3 days, but earlier is better than later) of the first that shouldn't be problem. Same with the 282.

That epoxy sticks like sh.. to a wool blanket. When I shot it on a sandblasted diff some got on the open centre section that hadn't been cleaned other than wiped out. I'll be damned if it didn't stick to the cast in spite of the oil.

Any chance you forgot to add the catalyst or mixed the two up?

Steve g

[my928s4]

I use those same products in the same fashion as you and have never had that problem. The recoat window would be my first question. I generally only use one coat of epoxy, but as long as the second was applied within the recoat window (3 days, but earlier is better than later) of the first that shouldn't be problem. Same with the 282.

That epoxy sticks like sh.. to a wool blanket. When I shot it on a sandblasted diff some got on the open centre section that hadn't been cleaned other than wiped out. I'll be damned if it didn't stick to the cast in spite of the oil.

Any chance you forgot to add the catalyst or mixed the two up?

Steve g

Thanks for the input Steve, there is always the chance I did something really dumb like you suggest but to the best of my recollection no. I shot this panel about a month ago.

On the 2nd panel (passenger front) which was shot approx 2 week after the first panel I did heat the garage up to around 70 instead of 60.

I will go down to the store where I purchased the paint to see if they can help, I must admit the Epoxy was the last thing I was expecting to have issues with.

Chris