Trotec Engraving Brass Question

[John Bion]

I would like to use some Trotec Engraving Brass in conjunction with Thermark, using my 60w (Chinese) Laser. I would appreciate any pointers. If I am unsure of the finish, before I remove it from the laser, can I re-hit it? I understand that the Thermark my not “anneal" to the brass as it does on Stainless Steel, so I would really appreciate any advice.
Thanks in advance, John

[Chris J Anderson]

Hi John,

Yes you can 're-hit' it if you mean run the laser over it again.

But it appears from my reading here and my own experience that very rarely does thermark / cermark work on brass or, really anything other than stainless.
I have tried on uncoated brass with smooth and brushed coatings, and the results are nowhere near as nice as stainless steel.

I would NEVER offer to etch a marking material onto anything other than stainless, and even then you need to be sure that its not coated etc.

[John Bion]

Thanks for your reply Chris. Yup, Dave Sheldrake had already warned me that brass was a problem and that it was not uncommon to have a great looking job, only for it to return to you at some point because the engraving had disappeared. My question really revolves around the Trotec Engravers Brass, which they specify as being good for Laser engraving with Thermark, hence my asking here, since I thought that someone here would have tried it :)
I will try upload a picture of a piece I did last night (with a clock hand for scale). This *looks good* but the warnings Dave gave me are ringing in my ears!
Kind Regards, John
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[Bryan Jater]

For the best results on Brass you need to ensure that you coat it straight away after removing the protective coating. It also helps if you heat the brass up before lasering.
Use as soon as possible and clean.

[John Bion]

Thanks Bryan, How do you clean yours, run it under some water? I wiped the pictured sample off with some paper towel and ended up with a load of micro scratches.
Kind Regards, John

[Dave Sheldrake]

CZ120 (Engravers Brass) is just the usual CZ103 with the addition of 2% Lead John , it's to stop it sticking to rotary tools.

If you go to a sheet supplier and ask for CZ120 it's a hell of a lot cheaper than buying it as "Engravers brass" ;)

cheers

Dave

[John Bion]

Thanks Dave, your advice has been much appreciated :)

[John Bion]

Dave, would the CZ103 (that term makes me think ‘pistol' not ‘brass’ ;)) be ok for cutting on my router or would I have to get it custom cut elsewhere? Also, if using brass for outdoor signage, would you coat it with something or leave as is after engraving? Thanks again, John

[Dave Sheldrake]

From memory I think CZ103 is pistol brass as it happens :), as in ductile that is used to draw cartridge cases.... will check for you brother

I'm not the guy to ask engraving questions past ones that relate to the material properties, I don't do enough of it to really offer much my friend.

cheers

Dave

[Kev Williams]

I've been tool engraving brass plated Norway cowbells for 14 years, and started lasering them about 5 years ago.

My 25 and 40w 'western' lasers make a nice mark, but I can wash 90% of it off with water and a toothbrush. Cleaning all the Cermark off and leaving black is a trick. I just rinse with nearly hot water and dry them with an air hose. Then I give them 2 good coats of clearcoat, which is the only reason I can get away with lasering them. Lucky enough that I HAVE to clearcoat all bells anyway, too keep them from tarnishing, and to keep the tool engraved letters from rusting.

That said, I am able to get cermark to stick quite well to these bells with the Chinese 80w laser. I can brush them quite hard and the black remains. How well it would remain during a scotchbrite or steel wool test I'm not sure. With the clearcoat it doesn't matter. My one issue with the 80w laser is the same I have with doing stainless in it, which is the mark I get is more GRAY than black. Thankfully, the clearcoat also takes care of that problem too...

I once laser etched a nearly all-black silhouette scene of a pilgrim woman pulling a cart on an 8 x 11 piece of brass with my 40watter. Turned out great, until I rinsed half of it off with warm water. And the half that stayed wouldn't come off. I ended up reproducing the exact image for tool engraving and painting.

Bottom line, if I can't clearcoat it afterward, I won't laser etch brass...

[John Bion]

mmmm, thanks to both of you, Kevin and Dave. I will go give the test piece I have done some scotch-brite to chew on and see what happens. Kevin, I can’t get BLACK on my stainless either, it’s not bad, but not JET BLACK either. I have tried up and down the scales off speed/power/scan-gap but not quite got it right.
I really appreciate the replies.
Kind Regards, John

[John Bion]

Out of interest I gave this test engrave a vigorous scrub with wire wool. Obvious deterioration but still visible, much to my relief, just hope that this is repeatable .....:

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