Black Anodized Knives

[David Dustin]

We have a bunch of Black anodized knives to be engraved.

The problem were are seeing is the lettering does not turn out as white as it does on other anodized materials (anodized Aluminum for example).
It turns out more of a gray color.
The knife is made of 440 stainless, and is made in China.

Is there a way to get better contrast?

I have tried low power, high power, multi passes, and the results are the same.

I have read here where it can be related to the anodizing.

The Black anodizing is not a Black, Black, meaning it is kind of a medium Black (hard to explain).
Thanks,
David

[Mike Null]

David

I suspect that the finish you are describing is oxidized rather than anodized. My limited experience with oxidized steel is that the laser will make a mark but it is without the contrast you are accustomed to with anodized aluminum.

[David Dustin]

I used the high density optics on the blade.
Perhaps i need to try the 2.0 lens.
Any ideas?

Thanks,
David

[Mike Null]

David

Some others on the forum have done some work on guns with this finish. I don't recall whether they posted pictures but you have the same mark I got.

[David Dustin]

Well I think it will be acceptable.

Using the High Density optics on stainless is not going as well.
There are some that mark well but it's a little hit and miss.

So far cermark blows it away for speed and appearance.

David

[Scott Shepherd]

I don't have the HD Optics, but I have had several detailed discussions in reference to it, based on some jobs we were quoting and thought it would be perfect for. One thing I recall being said was that the HD optics is EXTREMELY critical when it comes to focus. Normal lens can be off a little, where as the HD version had to pretty much be dead on. So if you have a knife blade that's tapered, my guess is that you're going to have issues. The fix would be to make a small fixture that holds the engraving area parallel to the engraving axis, rather than allow it to sit on the handle and have the blade tapered.

Not sure if that's the problem you're having or not, but it's something I thought I would add in case you hadn't been told that.

[David Dustin]

Steve,
I think there is an element of missalignment, and your idea could be implimented.

The biggest problem is the gray vs. white mark regardless of the alignment.

David

[Ross Lowry]

I might be mistaken, but when you laser a piece that is anodized you are actually lasering away the anodize and what you see is the metal underneath.
Maybe its just the color of the metal underneath?

[David Dustin]

Well when you lase anodized alumium you basically bleach out the anodized material and it turns white.

I agree there might be some other reaction taking place..

David

[Scott Shepherd]

Mike's already nailed it, Stainless isn't an anodized product. So you won't get the same results as anodized aluminum.

Not sure what it is, as there are a handful of black treatments available for knives.

I can't offer any advice on it, and I only wrote this to those who might be reading and offering advice for anodizing, which it isn't.

Like Mike, I'm sure someone who's messed with gun parts can probably lead you in the right direction.

[Dan Hintz]

If it IS anodized (and not stainless), the quality of anodizing dye can be a large factor in your white versus gray dilemna. Cheaper dyes (or improperly applied dyes, such as not setting the current correctly during the anodizing process) will have a more gray appearance when lasered.

[David Dustin]

No they are 440 stainless blades.
Is there any coating I can put on it to yield a white mark?

Thanks,
David

[Roy Brewer]

Is there any coating I can put on it to yield a white mark?
No. Sorry, but you've got all you're going to get with a CO2 laser source. If you need brighter/whiter, job them out to someone with a "YAG" wavelength system.

[David Dustin]

Won't a YAG just burn off the coating altogether?

[Mike Null]

David

Some time back this topic came up and I called a knife company in TN. I think it was Buck. Anyway they told me about the oxidizing and about the effect you get with lasering. Give them and call and ask for tech support or engineering.

[Eric Allen]

No they are 440 stainless blades.
Is there any coating I can put on it to yield a white mark?

Thanks,
David

I've been meaning to call Ferro on a product that looks like it's advertised for dark metal. I was wondering if it might be that Gold colored coating, and no telling if it would bond with the coating already on the knife. I've done some knives with your result, I've just burned away the coating if someone wants a brighter end result, so it kind of depends on the customer. I don't know why they would worry about 440 exposed, but you'll always have that guy....:) In any case, the product is "LMM 5001", maybe it would be worth checking. It just says it's a "bright metal mark" that can be used on darker substrates.

[David Dustin]

Thanks, I placed a call and left a voice mail.

I'll let you know what he says.

David

[David Dustin]

The fellow called me back and indicated the 5001 was no longer available.

He said they were still working on getting colors to work correctly.

There is one color that is working reasonably well and he asked for a sample knife from me to test on. Then he said I may be able to beta test it. How cool is that?

Thanks for the tips...
David