Die-Back problem with RM and Universal Clear

A

angus6643

Member
I get die back every now and then im trying to figure out what im doing wrong.
I am painting a 75 Mercury Cougar for a customer and over the weekend I painted all the jams.

Saturday I put 2 coats of SPI epoxy on all the jams let sit till Sunday morning. I based everything with RM Diamont Mixed 1-1 with SPI medium reducer. I let that sit 2 hours and then 3 coats of universal clear, using the slow activator, 1/2 hour between coats. The Shop is 75 degrees.

The only thing I can think of is the reduction of the paint, RM tech sheets say 2-1 0r 1-1 reduction. Maybe I should reducing 2-1 instead of 1-1. Does any one think that could be my problem.
 
Is the epoxy reduced? What are your metal temps when sitting overnight in epoxy? Shop stay at a constant 75 degrees?
 
what color? I remember Barry saying that some darker colors need extra time between base and clear or you have a greater risk of die-back
 
Most die-back questions are real easy to answer and this one is not.
First your question 2:1 vs 1:1, the 1:1 will dry faster than the 2:1 but may not cover as well and with a color like copper, did it take a lot of coats to hide- that could be the problem BUT diamont is pretty fast and you gave it plenty of time, so I'm not sold on that is the problem but 99 times out of 100 the base is the problem (trapping solvents).

This leaves the epoxy or letting the fan run too long after painting.

Sounds to me like you did everything perfect, sooo fan????
 
Reduced at 1:1 it took 3 coats to cover . I would say i let the fan run about 10 minutes after the last coat to clear out the over spray.
 
I Have had this die back problem before even when i used all Rm products paint,reducers and clear. I have always mixed RM 1:1 and have never needed more that 3 or coats, so that made me wonder if 2:1 would be the problem.

With Barry Thinking fan and it taking about 10 to 15 minutes to clear the booth of over spray may be its a air movement problem. with all the parts it took about 16 oz of clear each coat.
 
Two coats of fresh epoxy will pull in considerable amount of solvent from your basecoat that will then need to go through the clear during cure which causes the loss in gloss, to much product to fast. If your going to paint over two coats of epoxy after less than a full day of cure you should let the basecoat breathe longer before applying the clear or a better proceedure would have been to shoot your two coats of epoxy for the protection the job needs and allow it to cure a week, then scuff it and shoot one thin reduced coat of epoxy, then your base and allow it to breathe overnight before applying the clear. Hope this makes sense, it's all about not trying to trap solvent. What is fine for the collision shop jamb job usually isn't for show car type work. Just my opinion though, others may vary. Epoxy doesn't it's full potential as a solvent barrier untill full cure is reached-you can confirm this by spraying it over a 1K lacquer type product then allow it to kick for 24 hours then shoot some lacquer primer over it and see what happens.
 
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