Spray Painting Woes


The goal: to change the color of a few new, factory-painted steel parts. I
lightly sanded all surfaces with 800g emery paper. Cleaned up with denatured
alcohol. Sun dried.
First coat of spray enamel went on and dried to a fine gloss finish. Dried
overnight inside and put outside again in the sun while I was at work for a
thorough drying.
Came home, lightly sanded again, cleaned with d.a., dried, and sprayed a
second coat.
Almost immediately (less than 10 seconds) the coat took on a curdled look.
Sort of wrinkled. Not "orange peel", but it looks like the cracks in a dried
lakebed. This effect was apparent on all parts I sprayed with a 2nd coat, not
just one.
What did I do wrong?
Obviously I'll have to dry it, sand down to the original finish and do it all
again.
What should I do differently?
Paint is Rustoleum "industrial strength" enamel.
Thanks.
Reply to
DaveC
Loading thread data ...
Look at the can, it probably says recoat within an hour or wait two days(or more). When they say that, they mean it, and the wrinkle finish you now have is the result of not waiting long enough. The new coat dissolves the old one and the contraction of the new coat setting up is enough to wrinkle the coat underneath. I have had this happen with Rustoleum primer under their spray paints, it's NOT my favorite brand. They changed formulations back when CA CARB board decided spray paint V.O.C.s were an environmental hazard and it's sucked ever since. It's slooooow drying, it forms a film that keeps it from completely drying and it's too heavy, it runs. I've used a touchup gun instead of spray cans ever since.
Chemical paint stripper is the answer if you've got a fair amount of surface to clear off, beats hours spent with a sander.
Stan
Reply to
stans4
RCM only
On Mon, 31 Aug 2009 21:58:24 -0700, the infamous DaveC scrawled the following:
I wouldn't sun-dry anything metal and I wouldn't use the alcohol between coats. I think the alcohol was your most likely culprit unless you sprayed HOT parts, right from the sun.
-- Good intentions will always be pleaded for every assumption of authority. It is hardly too strong to say that the Constitution was made to guard the people against the dangers of good intentions. There are men in all ages who mean to govern well, but they mean to govern. They promise to be good masters, but they mean to be masters. --Daniel Webster
Reply to
Larry Jaques
I skipped over most of this thread but someone explained that real enamel has a narrow window for re-coating, and that it will wrinkle if you miss the window. Rust-O-Leum itself points out that the re-coat window varies *widely* on their different products. They have a lot of information on their website.
Most of their heavy-duty enamels are alkyds and modified alkyds, and some of them are very slow driers. But they'll develop a skin very quickly. When the OP mentioned that he sanded between coats my first thought was that he had one of the quick-drying ones, but then I remembered that their paints can develop quite a thick skin and still not be cured enough to re-paint.
I did one job (but with their fish-oil paint, 45 years ago) that wrinkled, and then the top coat peeled right off like a sheet of Saran wrap.
-- Ed Huntress
Reply to
Ed Huntress
From the Rustoleum site: " Strong solvents can also soften a previous finish and make your new paint application susceptible to wrinkling. " and " If you sand in-between coats, allow the full recoat time to dry before applying another coat (at recommended drying temperature). "
So I guess sanding after 24 hours exposed not-yet-dried paint and the alcohol softened it further.
So recoat within 1 hour or wait 48 (as the can says...).
Thanks to all who contributed to my education. :-)
Reply to
DaveC
There were paints sold to do this *intentionally* -- called "Wrinkle Varnish" paints -- and were quite common on electronics (and electric fan bases) for a while. I used to use it when General Cement sold it in rattle cans. If you paint -- let dry for a short while, and re-paint, you get a wrinkle effect. If you want a coarse one, let the second coat dry naturally. If you want a fine and tough coat, dry it in the oven on low for an hour or two.
I had only black, but it came in gray and blue as well, and probably other colors.
Here's the URL for a patent on an intentional wrinkle varnish:
Apparently scanned, with quite a few missed letters which are showing up as checkerboards.
Hmm ... if I *want* a wrinkle finish, that may be the way to god now, since I can't seem to find intentional wrinkle varnish products any more.
Good Luck, DoN.
Reply to
DoN. Nichols
You can make your own wrinkle paint. I did a dashboard for a racecar with homemade wrinkle paint, and it came out great.
That was 40 years ago, so don't ask me what's in it. It was just ordinary enamel with something ordinary added to it. I'm sure there are formulas for it around the Web.
-- Ed Huntress
Reply to
Ed Huntress
*Snip*
For anyone who's interested you can buy wrinkle paint spray cans at most FLAPS (Friendly Local Auto Parts Stores) which, oddly enough, is marketed as for restoring car dashes. The stuff I have is Plasticote #217.
H.
Reply to
Howard Eisenhauer
hi ,
dont wait too long between coats , either wait 5 min between coats . OR wait at least 3 days if you HAVE to rub it and spray it agian..
Reply to
no one
I like and use the referenced paint. My recollection is the instructions on the cans dictate that you finish recoat either within 1 hour of your last coat or after a minimum period of 48 hours from your last coat. The period in between is a no-go painting zone.
Obviously, humidity and temperature may skew standard guidelines. Not applying it in an area where daytime mercury or ambient moisture is ever a problem, I don't immediately recall qualifications for the directions specified.
The Rustoleum people are accessible. You might want to call them for counsel on your particular conditions.
Regards,
Edward Hennessey
Reply to
Edward Hennessey
DId some crusty old server get spun up and just dump some archived threads here or what? Original posting was 2009!
Stan
Reply to
stans4

Site Timeline

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.