Need Settings for CO2 Laser for Ka-bar knives with black finish

I've been struggling with getting a clean burn with my CO2 on the black finished KaBar knives. Using my 40-watt epilog mini, it took about 5 runs and then a trip to the buffer to get anywhere near an acceptable engraving. It still looks a bit blurry and "over-exposed" with the loss of detail. See the photo.

Anyone willing to share what's worked for them? I still need to run about 5 more blades and would like them to turn out better. I've got both 75-watt & 40-watt machines (don't ask me why I started with the mini?)

Attachment 433901

Thanks for any input

I don't recall my settings but I do remember doing 2 passes (only) since the first one always left a slag of paint/coating. I remember using simple green to clean them (and it always turned the rag pink). Never had to use a buffer. What settings are you using?

Quote:

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Originally Posted by Bruce Clumpner

I've been struggling with getting a clean burn with my CO2 on the black finished KaBar knives. Using my 40-watt epilog mini, it took about 5 runs and then a trip to the buffer to get anywhere near an acceptable engraving. It still looks a bit blurry and "over-exposed" with the loss of detail. See the photo.

Anyone willing to share what's worked for them? I still need to run about 5 more blades and would like them to turn out better. I've got both 75-watt & 40-watt machines (don't ask me why I started with the mini?)

Attachment 433901

Thanks for any input

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I only have a 25W so I use GSLA RD-6150 Pearl Metal Marking Material... JDS and Johnson Plastics are on the Distributors list. LMM 6150 Pearl

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Hey Chris,

good tip with the simple green, I use ZIP 505 which didn't really work on the slag. I started at 100% power and 50% speed at full frequency, then progressed up down to 15% speed. Maybe I'll hit it with the larger laser next time?

I'm not understanding-?

I'm not familiar with KaBar knives-- What kind of coating is on the blade? Is it thick, thin? Are you just bare-bones engraving or using any kind of Cermark?

It's been a long time since I've engraved a black knife with a C02 (the fiber does just a phenomenal job!)
Attachment 433949

I blew up your photo--
Attachment 433950
--the engraving looks 'mottled', which I wouldn't expect from a C02, as it appears the metal is mottled.
Is that the paint/coating, that refuses to burn away clean?

The only suggestion I have at this point would be to try the 'less is more' approach, like 20% power, around 50% speed and up the resolution some (if slag is a problem)--

Bruce
I do some Kabars for a Marine unit here but I use a diamond.

Attachment 433991

Hey Kev,

The coating/paint is pretty thick. Not sure if it's paint or cerakote, but it's tough. So I did as you said, started low and fast to see how the paint reacted. Didn't dent it at low power, kept upping the power and lowering the speed to get where I finished. I believe it's paint slag, as the metal in the sharpened areas of the knife seem smooth enough.

I wish I had access to a fiber. Anyone in the OC with a galvo willing to help me out and take a shot?

Thanks.