924Board.org

joecitizennn · Joined: 12 Sep 2005 Posts: 2096 Location: no mans land

I have been prepping my 944 and found that the paint peels off the hood alarmingly easily. Everywhere else on the car is solid and I just sanded it. For some reason the factory paint did not seem to bond to the hood very well and I can see alot of galvanized flakes and dust. Any ideas on prepping this right so the paint sticks?

Scorpio · Posted: Fri Apr 02, 2010 11:53 pm Post subject:

start with a good etch primer
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

Smoothie · Posted: Sat Apr 03, 2010 12:02 am Post subject:

Not sure about etch primer - it may or may not be good over galvanized, but I'm having a vague recollection of it not being good over galv..

I was told that 2-part epoxy primer is best for topping galvanized.

Also, if any body filler is needed, that goes over either bare sanded metal or lightly sanded epoxy primer. Body filler directly applied to galvanized steel is not recommended.

More here - http://www.924board.org/viewtopic.php?t=19177&start=15
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Would an adhesion promoter help?
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erstwhile owner of just about every 924 variant ever made

joecitizennn · Joined: 12 Sep 2005 Posts: 2096 Location: no mans land

how about just sanding down to bare metal? I dont give a hoot about galvanizing on the hood, its not going to rust.

Scorpio · Posted: Sat Apr 03, 2010 8:58 am Post subject:

Most of the etch primer ive used has stated on it that it can be used for galvanized metal and fibreglass...i guess it comes down to which product you find..

this is what im using

http://www.conceptpaints.com.au/technical/pdf/Primers/1KEtchPrimer-Black05.pdf

http://www.conceptpaints.com.au/

i have the 1K etch primer and the universal 4000 primer...The universal 4000 primer seems to hold really well so far

concept paints------technical information-----primers
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

Bryan M · Joined: 19 Jan 2011 Posts: 37 Location: Tampa

i know this is nearly a year old, but i didn't see it mentioned. i thought i'd post for future reference.
diluted phosphoric acid. spray with a spray bottle. or wipe liberally with a soaked rag. allow to sit for 20 minutes or so. wash with soap and water to neutralize, then prep as usual.
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'69 912
'79 924

Scorpio · Posted: Thu Mar 10, 2011 2:52 pm Post subject:

A year in and my concept paints etch primer
Is still super strong , I couldn't peel it off if I tried..
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!