I put this on the tail-end of another post; but I believe it belongs better here, where it can be discussed.
After exhaustive testing and unbridaled expense, I've come up with an illustration of what will, and will not, stick to powder coating.
The test panel was a piece of scrap 3/16" aluminum composite, with red powder coating. I wiped it down twice, with Rapid Prep, then marked the approximate center. I then lightly sanded the right side of the panel with 150 grit sandpaper, just enough so the bare aluminum is beginning to show a little. Remember, powder coat is very thin and doesn't require much sanding.
All the painting was done last Friday, Dec. 20, and the piece has been allowed to sit in the house since then. These were paints I had on hand, and have used on a regular basis...nothing special. The "testing" was done on the 26th, which is much longer than I usually allow painted work to sit, before lettering/finishing.
With using only my fingernail, none of the samples on the left fared very well; some failed totally. The ones on the sanded right side did much better. Sanding is definitely a key to paint adhesion on this stuff.
The 1 Shot with acrylic enamel hardener did great, as did the Zinsser primer (oil base) and the untreated 1 Shot on the bottom. The acrylics did pretty well too, but didn't seem to fare quite as well.
Gives a little insight on what may work, or not, for a particular project. What's still unanswered to me is how would you do any hand lettering, borders, or gingerbread-type of work on this stuff? Sanding the whole panel will ruin the factory finish. You can't sand JUST where the lettering or borders will go. And, as you can see, and as I've experienced, paint will not stick to this coating, without sanding.
Are these manufacturers trying to stop us from painting? Why would you buy these pre-painted panels, only to sand and paint over them again? They are supposed to be a replacement for MDO, that's also gotten worse; but here we have a whole new set of problems.
[ December 28, 2013, 12:34 PM: Message edited by: Dale Feicke ]
Posted by Joey Madden (Member # 1192) on :
Some twenty years ago the EPA changed the method so to speak for powder coating as most all coating today is Polyester. Twenty five years ago it was a coating which nothing stuck to. I have the grill in my 64 Signet which was done around 1988 and absolutely nothing sticks to it.. Our government uses a different coat yet a powder coat for it's weaponry, tanks etc as powder coating is older than all of us...
Posted by Glenn Taylor (Member # 162) on :
Dale, a few years ago I ran into a similar problem. I sent some sample pieces to Nazdar. The only thing they found that would stick to it was their thermoset inks.
The catch is that the ink has to be baked. Not a problem for me as I have a 5' wide gas dryer I use for my screen printing operation. But 2 minutes at 400 degrees and the ink becomes impervious to any scratching or peeling.
I found that I can use a vinyl mask, spray the ink on, remove the mask and run the panel through the dryer.
Posted by Bill Modzel (Member # 22) on :
We screen print a number of control panels and pretty much always use NazDar EB series, baking epoxy on them although I have had occasional luck with just enamel if baked at somewhere around 180° I think is was.
This was all with no sanding.
Posted by Dale Feicke (Member # 767) on :
Sorry guys, I'm not talking about screen printing or baking. I'm talking about those of us who still do hand painted work of any kind. Even though these are a good product, they are not conducive to any kind of paint work, directly on them, without sanding or repainting the whole thing and starting over from scratch.....which kinda defeats the purpose of buying pre-finished panels.
Posted by Dave Sherby (Member # 698) on :
Where are you getting powder coated panels? What brand are they? The painted aluminum panels I buy have had no problem holding One Shot, Latex, or automotive paint.
Posted by Joey Madden (Member # 1192) on :
Well Dale, from what I understand. 1-shot sticks to powder coat pretty well. Ask anyone who owns one of my KillerKarts...
Posted by Dale Feicke (Member # 767) on :
Sorry, Joey, but look at the picture above. In addition, I have a job out now, that I did some border and trim with 1 Shot. You can take your fingernail, or a piece of masking tape, and pull the paint off easily.
I guess, from the lack of response, this isn't a real issue, or no one else has encountered it yet.
