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Beth Page
09-13-2012, 10:18 AM
The pictures below are of a tool for a CNC machine I have to engrave. I am using Thermark to do it, well I have removed all of the oil off the tool but when I go to clean the thermark off i am getting the discoloring around the engraving and on other sections of the tool. Is there any advice you could give me so this does not happen or know why this is happening?


241088241089

Mike Null
09-13-2012, 11:11 AM
Thermark/Cermark can stain. Try polishing with a metal polish--even a brass polish should work.

These pictures aren't great but one shows staining the other where I removed it with a light polishing.241092241091

Martin Boekers
09-13-2012, 11:43 AM
Do these have a "protective coating"? I believe the Cermark/Thermark needs bare metal, hence the polish that Mike recommends.

Chuck Stone
09-13-2012, 12:08 PM
I wonder if the problem is low wattage on the laser? With a higher power you
can move faster. Perhaps that is giving the stuff more time to stain?
Just a WAG...

Gary Hair
09-13-2012, 12:20 PM
The wet Cermark/Thermark is what is causing the staining and Ferro recommends that you do a couple of things to avoid this problem.
1. Heat up the part so that the Cermark/Thermark dries faster
2. Spray from a farther distance away so that the Cermark/Thermark dries a bit before it hits the metal.

Almost guaranteed to work. If that doesn't work then you may need to mask the part before you spray. I had to do that for one job that was too large to heat and it stained badly. I masked it with Ikonics laser tape, (for sandblasting), lasered the mask, sprayed Cermark then lasered again. Fortunately the job was priced high enough that this multi-step process still kept me well above my hourly rate.

Gary

Dan Hintz
09-13-2012, 7:44 PM
Gary has it... mask, laser, spray, laser.

Mike Null
09-14-2012, 6:27 AM
I would use a sponge applicator and clean the area after engraving. Masking is more trouble than it's worth on this application.

I do a lot of Cermark and prefer spraying with an airbrush but the small sponge brushes are ideal for many applications and work as well as spraying.

Here is an example of where the sponge makes far more sense than spraying. I do several hundred of these a year.

Beth Page
09-14-2012, 5:15 PM
Thank you all for the advice. I went with masking it first, lasering, spraying, lasering agian and it works fantastically.