daver

not sure what forum to put this in for best results but.. could somebody please tell me which is the correct order when bare metal is exposed. I've read people saying both, but i'm looking for reasons why, hopefully from experts.

etch prime first and use the filler over the primer

OR

use the filler on the bare metal first and etch prime after to cover the remaining bare steel

ALSO

is it necessary to sand right dowen to the metal when fixing a dent? can the bondo stick to scuffed up paint ok? is one way more or less durable than the other?

thanks

d

blueoval557

search..this info is EVERYWHERE online..
bondo/filler MUST go on bare metal that is REALLY scratched up, with like 36 grit sand paper.
then your primer goes on. filler is the VERY first thing to go on
kyle

daver

oh i've been seraching, but i'm seeing conflicting answers. most do say to put the filler on bare metal tho.

but i did find out that you definately don't put filler right over etch primer, because it has acids in it that will react with the filler. the dude said etch prime the bare steel, prime, then filler.

i'm hoping to find some guys who do it professionally to tell me the right, or normal way. so far it sounds like - bare steel, filler, etch prime, prime, colour.

d

blueoval557

ive done MANY before. also...have u ever looked at the label on a can of body filler? u should try that too...it will tell you what to do....put it on BARE metal!

Race Egr

Actually alot of the top painters use epoxy primer on the bare metal then use filler,but most of them tryin use as little filler as possible. The reason for this is filler is porus which means it sucks in moisture and you dont want moisture on the bare metal because that causes rust

blueoval557

Thats what the epoxy primer and sealers are used for....to seal it, and keep out moisture.

Race Egr

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blueoval557 &raquo;</TD></TR><TR><TD CLASS="quote">Thats what the epoxy primer and sealers are used for....to seal it, and keep out moisture.</TD></TR></TABLE>

Yea thats why you use it on the bare metal before the filler

Wes V

Think about what you are trying to do and it all kind of makes sense.

You use etch primer directly on the metal due to the fact that it etches into the metal. It's not intended to etch into any prior paint.

Epoxy primer is a two part paint that seals anything below it. I like to use the PPG "DP" primers. It can be used to seal the surface of the metal and also to seal any earlier paint that may "bleed" into any other paint layed over it.

What was said in one of the prior posts has to be noted. Most body materials are porous! Most "fillers" and primers are porous. If you leave them on your car for any length of time, oil and water can soak through and rust the metal below.

As for "filler" type primers, I like K200. It's that stuff that looks like baby poop. It goes on thick and is easy to sand smooth as long as you don't let it set too long. It's porous also, so keep anything "oily" away from it prior to doing the surface paint!

And talking about "oily", don't take this personally, but you are oily!! Only touch the car with your hands after you are sure they are clean. It's real easy to get an oil spot on a body part that will cause fish eyes when you go to paint it. This is from experience, I'm oily also!!

I'm not a professional, but have been around the block. The problems you will run into trying to do a paint job at home are different than what a body shop would have.

Wes V

blueoval557

Great post Wes. I still dont understand what Napier is talking about. I just went out into the garage to make sure I was correct before I said anything else, and sure as ****, it says right on the side of the can..."apply only to bare metal surfaces". How much clearer can it be?
Kyle

Wes V

It's possible that the acid etch primer you have is real strong and may react to any paint that it's sprayed on. I'd recommend that if you want to use the product, spray a small amount on an area that you don't care about.

I've never felt the need to use an etch primer, but I wouldn't say anything negative about others that swear by it.

I do swear by epoxy primers!

Wes

daver

thanks for the responses.

the conflict i was having was my diy book said to bondo on the bare metal, so did most people in my research. that would seem to make the etch primer redundant eh?

but others said its good to put some kind of sealer or protection on the metal first, then bondo over that. As bondo (filler) is porous and provides no protection.

But in further research, i found that bondo over etch primer is a no no, as this primer contains acids that may cause the bondo to lift. But, there are "some" etch primers that say its ok to bondo over it.

Soooo, here's what i decided to do...

1 bondo right on the bare steel
2 block sand it down
3 etch prime the bare metal spots that showed up (as regular old primer won't stick to metal apparently)
4 regular prime the over it all (i have dupont acrylic laquer primer)
5 spray a guide coat of a different colour and wick sand off the high spots
6 glazing compound for any scratches (then more primer)
7 paint

...and of course wax and grease remover btw every step.

its been going pretty good so far. i've got most of the dents filled and primed. Just one bad spot where there was a crease and the metal popped through in my sanding. i'll have to hammer it down and refill.

i've found that when block sanding, as soon as metal pokes through, your done. The metal won't sand down further, only the surrounding bondo will get lower. so if there's any low spots that i didn't hit with the block sanding, i've got to knock the metal in a bit and start over.

one other thing, does that etch primer ever stick. trying to get it off is like trying to get rust off, either sandblast or sand down through a layer of metal.

d