Burn through paint layer

Community Laser Talk
1

I really didn’t know where to post this question. I have painted two layers on a clock hand and want to burn letters on the hand but only want to burn through the first layer of paint. Any suggestion speeds/power? I have tried many times and can’t seem to get it right.

Thanks as always,
AmyH

2

I believe you go higher speed lower power, without knowing your laser specs i’d be hard pressed to say exactly, however i’ve seen white tile two layer color done at 35% power / 6000 MM/M ish, there are lots of vids on the tubes on how to do stuff, still experimenting myself as i just finished construction on mine about an hour ago :smiley:

3

I have already tried 1000/30…to 1000/70 and won’t burn through, even 500/30-70 and a lot more, maybe it’s too hot, IDK! I wonder if the clock hand being metal makes a difference…even though no burning through to the metal.

4

Speeds and laser power are trial and error (or at least trial) type thing. I take a piece of white tile and spray paint it with 4 coats of spray paint in different colors with a thin coat of water based polyurethane in between each coat. The water based poly keeps the coats of spray paint from interfering with each other. Then I burn a test grid into the tile ramping up speed and power (there are a bunch of these test patterns floating around). With a little practice you can fairly reliably get tiles with 5 colors. I would imagine the same technique could be employed on the clock hands. I use a white tile as that is the final color (every other color being darker than white, they burn off easier than white paint would).

5

Makes sense. Thank you.

6

What about applying your outer color to the entire clock hand, let it dry fully, apply masking using high quality 3M blue masking tape (make sure it seals well) to the entire clock hand, burn the letters on to the clock hand through the tape, now spray/brush in the second color for the letters, let dry a bit, remove masking tape? The key is good tape and making sure it adheres well so that you don’t get leakage under the edges (cheap masking tape is notorious for leaking around the edges). Sometimes using a soft rubber rolling brayer right after lasering to confirm the just-etched tape is still sealed can beneficial. Don’t wait long at all between lasering and applying the second paint color.

7

I want to say I have no common sense, because this sounds so right. Thank you. I guess the way to do it would be “Mode” line to cut the shape out then peel off and paint?

Thank you
AmyH