Body filler question

[moose]

Greetings All, What is the current thinking about body fillers? In the old days everyone recommended that filler be applied over bare steel. With the new polyester fillers and primers there is a trend to apply filler over the base primer. I am getting ready to media blast the Coupe body to start final body work and want to have the best chance for long paint life!@

Thanks

Tim

[kb426]

You will read over and over to apply it over epoxy only. 1 of the people have stated that the heat from the bondo setting up will start the rusting process. If you read about the window for application over epoxy, it makes it real difficult to do for us weekenders. I'm still usually applying over clean and properly sanded metal. The 32 is 9 seasons old and I haven't had any fall off yet. If I lived in a humid area, I might feel entirely different about this. Living in the desert might have an advantage. I'm just a guy who has done this occasionally my whole life. I'm a long ways from an expert.

[enjenjo]

I have the best results putting the filler over epoxy primer. I use DP40LF, or DP90LF depending on the color. There are other brands, I have used Autobody Master brand with similar results.

The advantage to using Epoxy primer first, it is water proof, and will seal any pin holes keeping water away from the filler on the back side.

[idrivejunk]

I am from the filler-over-sanded-epoxy camp and believe that method offers the best chance for long life.