Mil thickness of epoxy before filler

danp76

danp76

Oldtimer
How crucial is the mil thickness of epoxy before applying body filler. I have always thought a good coat or two would be a good foundation before filler. Some epoxies only want a mist coat or very light coating, like 0.5 mils before applying body filler...why is this? Is it bad to have some mils below body filler? I usually sandblast, 2 or so good coats of epoxy, and 24hrs-7days later apply filler. If I'm beyond the 7-day window, I scuff with 180 and then apply my fillers/glazing putties.
 
Some epoxies do not take fillers well, so follow the manufacturers instructions.
SPI epoxy, I prefer 2 coats for all high end work.
 
Thanks Barry and Shine, I'm doing an "all Glasurit" job, as this customer wants it on his car. You guys wouldn't believe the prices, well maybe you would but let me tell you$$$...I just bought a gallon of 2k dtm primer $277.00 and $116.00 for the hardener!
 
Dan, That paint line is one of them, I was talking about, keep it at one coat like they say.
 
Thanks Barry, I'm not sure why I couldn't put on a good coat, like the SPI epoxy, and then scuff it and rely on mechanical adhesion. They want almost a mist coat, wait 30 mins and then apply filler, they don't want hardly any mil thickness under epoxy for some reason.
 
Because it will blow up! They sold their soul and the epoxy is made for production shops now where speed is king.
 
danp76;38458 said:
Thanks Barry, I'm not sure why I couldn't put on a good coat, like the SPI epoxy, and then scuff it and rely on mechanical adhesion. They want almost a mist coat, wait 30 mins and then apply filler, they don't want hardly any mil thickness under epoxy for some reason.
Click to expand...

I would bet it's speed related-collision shop environment. I've done one coat of SPI and applied filler within a few hours and never had a problem but I prefer to shoot two-three and wait overnight.

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danp76;38458 said:
Thanks Barry, I'm not sure why I couldn't put on a good coat, like the SPI epoxy, and then scuff it and rely on mechanical adhesion. They want almost a mist coat, wait 30 mins and then apply filler, they don't want hardly any mil thickness under epoxy for some reason.
Click to expand...

I would bet it's speed related-collision shop environment. I've done one coat of SPI and applied filler within a few hours and never had a problem but I prefer to shoot two-three and wait overnight.
 
i would use their base and maybe their clear but i doubt i would use their primers or epoxy. i have not used them in many years but did a lot of euro cars years ago with it. back then it was the only match for color .
 
Customers don't get to dictate my material choices. They don't need to, since I have already done the homework for them, and I only use the best stuff I can find. If a customer really thinks they know better than me about refinish material, they should be holding the gun, not me.
 
I hear you Crash, before using SPI I always used BASF(Glasurit and RM Diamont). I have had great service with both SPI and BASF. Glasurit is one of the few companies still producing a chromated epoxy, which might be overkill but the stuff is like iron and bonds like no other. My only complaint with BASF is $$$. I do like that Barry is available for friendly fast advice for technical assistance, unlike the big brand companies.
 
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