I must be doing something wrong after 24 hours of drying I can scrape
the primer off with my thumb nail.
I am trying to paint aluminum. I use the following steps:
1) clean with acetone
2) remove outer layer of oxide with scotch brite pad
3) clean with acetone
4) place in Alumiprep 33 for 3 - 5 minutes
5) rinse with water
6) place in alodine 1201 (the gold stuff)
7) rinse with water
8) dry
9) paint (within 8 hours) with zinc Chromate primer (Tempo 5605C).
10) let dry.
It has been 24 hours since the zinc chromate primer was put on and I can
scrape it off with my thumb nail.
Any suggestions on how to get it to stick better ?
thanks
Rob
Rob,
My experience is that Zinc Chromate from the Tempo spray cans is extremely slow
to harden. If you'll leave it alone for a few weeks before trying the
thumbnail test, you'll get much better results.
KB
assa9
Kyle Boatright <kboat...@aol.comnobs> wrote in message
news:20020128180510...@mb-dd.aol.com...
Robert Schieck wrote in message <3C55A551...@mers.com>...
Rob,
I had a similar experience and was guided by an old pro who had
designed and built many metal aircraft. His suggestion was to clean,
alumiprep, rinse well and then coat with a two part etch primer
followed by zinc chromate.
I did just this and the results are great. The etch primer gives the
much needed tooth for the zinc chromate and provides a molecular bond
with the aluminum. Whatever you top it with will stay put.
Good Luck,
CH
My problems are quite simple, no patience, no patience and too much
primer....
Many thanks
Rob from Ontario Canada
I am priming my RV7A wing ribs and it is sticking great.
1. scuff with scotch brite
2. clean with a paint prep
3. prime with NAPA part#7220 self etching primer (grey) out of a spray can $5 a
can
Wait 30 min. dry to the touch wait an hour and do what ever you want to it.
I had the tip on one can mess up and the primer was pouring out, wiped up the
puddles waited about 30 mins.and was going to lightly scuff the area to smooth
and reprime. Wrong I had to scuff very hard to smooth it out, so I do not think
it would scratch off.
--
Surfing the Web from Hopkinsville, KY
Visit my web site at: http://www.geocities.com/hester-hoptown/RVSite/
Starting RV7A wings :-)
Putting zinc chromate over two part etch primer is a waste of
time, money, creates dead weight and probably weakens the bond
between the finish and the primer. Used properly, zinc chromate
(.0005 thick) forms a chemical bond to the aluminum surface as
does the two part etch primer. There is no reason to use both.
Ray