Surprise Finish!

I recently laser engraved an electronic gizmo box front panel. The panel was finished in a powder coated light blue paint. I had no idea how it would come out and was expecting the worst (hardly visible/laser doesn't touch it etc.) but I was actually completley surprised by the result. The lasered logo/writing ended up a nice shiny gold color! It looks great (photo to follow soon if I can get permission to show it - if not, I'll make another panel to show it off).

Anyone else notice this great finish before? Is it safe to laser powder coated paint (chemically)?

I wonder.....if I powder coat paint a panel in black, will the lasered bits still go gold? That could be good for plaques. Experiments needed......

Dave F.

One of the fun things about the laser is that when you try a new material you never know how it will come out. Often, as in your case, it's a pleasant surprise. Sometimes it's not at all pleasant.

Unfortunately the powder coat resins may contain vinyl. The principal resins used in thermoplastic powders are polyethylene, polyvinyl, nylon, and fluoropolymer. Thermosetting powders use primarily epoxy, polyester, and acrylic resins. Unless you know what's being used and see the MSDS on it you are taking a chance, though if it's a small rastor job the risk should be minimal. Before taking on several hundred of these I'd make sure that there's no vinyl.

No worries Joe, this was a one-off job for work. I'm a hobbyist only. I made sure to clean everything thoroughly afterwards too, so I don't suppose there will be any long term damage.

Cheers,
Dave F.

The vinyl won't hurt anything, just make sure there isn't any PolyVinylChloride (PVC) in it. It is the Chloride that results in a Chlorine gas that is the problem. It is toxic and highly corrosive.

I know this is an old thread but just in case anyone is reading through the archives like I am . . .

I am guessing that the part had a yellow or gold finish to it before painting. Perhaps it was yellow chromate on steel, then painted. It is not necessarily common practice to plate and then paint but it would depend on the application. The same idea is used to make painted plates for laser engraving - they brass plate a sheet of steel, then paint over it. The laser ablates the paint and you see polished brass underneath. I don't know what kind of paint the plaque manufacturers use.

In some cases if you laser powder coating you will hit bare metal. This wouldn't be so good as it would corrode. But if it was followed by paint fill and/or some kind of clearcoat it might work. If a manufacturer wanted a colored panel it may be possible to paint twice. Then you could laser through the first layer of paint and expose the underlying color. At least in theory . . .

A good theory Richard....but in this case, the panel is made of aluminum and has a primer followed by powder coated paint only. The engraving (raster) didn't make it all the way through the paint even. I think it was the primer that turned this nice gold color. I'll bet I couldn't reproduce it if I tried.... :)

Cheers,
:Dave F.