I was just reading an article on a guy and his bodywork to his car and he said its best to put filler over the first layer of etching primer?? Could someone please explain this?

Thankyou.

I apply mine over epoxy primer.

I prefer to put it on bare metal that's been sanded really good. I think it will hold better and it will smooth out easier, because fillers and primers will sand down at different levels. But I have done both. Just when you think you found every lil ding you always seem to find another after that finished primer coat.

You can apply filler both ways, over bare metal or over epoxy primer. Body filler is like a sponge, it absorbs water, that's why some folks like to put the filler over epoxy primer to provide a moisture barrier.

I would never apply filler over top of just self-etching primer. All self-etching primers I know of mandate a top coating of regular primer in a timely fashion. 30 minutes or so.
For 'deep' filling, it's best to apply to bare metal that's been ground with a 36 grit grinder. That provides the best adhesion to the metal. More 'tooth' to hold it. Once you've applied the filler and sanded it accordingly with 80 grit or higher, then apply your self etching primer and top that with urethane primer/filler. If you come up with low spots you can still use filler on top of that with out problems as long as you keep it thin. Evercoat makes some good fillers that are for urethane surfaces. Always remember not to mix the stuff too 'hot' (too much hardener) or it will shrink down the road, even though they it won't shrink. It will if you don't follow the directions.

------------------
Triple Black 69 SS 396

[This message has been edited by Jimmy P (edited 04-20-2001).]

In their product sheets Sikkens states clearly not the use filler over self etching primer (wash primer). Use filler either over bare metal or epoxy primer.

Ok thank you guys for the info.