Thermark on aluminum, 2-tone black/grey

[David Ford]

Hi,

I did a search before posting this question and didn't find a suitable answer so here goes. I have a logo to etch on bare aluminum (18"x10") that has black lettering and a grey object/shape in the background. I have a 25W laser and a spray can of Thermark LMM14. My question is this.

Can I simply spray the aluminum plate, laser the entire image in one shot, wipe away the excess Thermark, and expect to have the logo show up as intended, in both black and grey? Or do I need to separate the 2 colours and run the job in 2 passes, one black, one grey? If so, any Thermark specific recommendations on how to do this?

Thanks very much for any advice passed my way. I will post a photo of the finished product when it's done.


Cheers,
Dave

[James Stokes]

First off your 25 watt laser probably will not have enough power to mark the aluminum. If it does you will probably have to use a speed of around 2 percent. Theramark only marks black, if you run the image through photograve it should dither the gray to make it look mor gray but not a lot. What you should really do is put a very small white outline around the lettering to seperate the 2 objects.

[Dave Johnson29]

Can I simply spray the aluminum plate, laser the entire image in one shot, wipe away the excess Thermark, and expect to have the logo show up as intended, in both black and grey?

Hi Dave,

In my limited experience with Thermark I seriously doubt you would get black and gray it would all come out black.

However, I have had zero success in using Thermark on aluminum with my 25W ULS. It seems to conduct the heat away too fast to get a high enough bonding temp.

[Scott Erwin]

I would think something like this would be better suited as a vinyl sign. The design is very simplistic and has only 2 colors.
Not too sure of the environment it is going into, but vinyl may be your best bet for this one. Vinyl can last up to 7-10 years depending on what grade of vinyl you use.

[David Arana]

I agree with the vinyl method. You could even layer the grey vinyl.

[Bill Cunningham]

I don't know what kind of laser you have, but if it's a epilog, you can send it as a greyscale in the clipart mode and the driver will halftone it to the metal. this works with photographs to stainless using cermark.. Try it at 300 dpi, full power, at the slowest speed your machine will go .. But aluminum @25watts may not be possible..

[Mike Null]

I think you'll have to run the laser at 1000 dpi.

[Dan Hintz]

Most comments above are valid, but gray is possible by overpowering it in some circumstances. Not sure if you can do that with only 25W, but if you can it would have to be dirt slow (like <1S).

[Dave Johnson29]

Not sure if you can do that with only 25W, but if you can it would have to be dirt slow (like <1S).

Just a thought, bumping the DPI up to max and rastering in the short direction might saturate enough heat into the thermark and substrate.

Turn the artwork through 90-deg and maybe the overlapping passes will make it stick.

I don't have the time to try at the moment. Might be worth a shot.

[Brian Robison]

Dave,
is it an Epilog?
Is the aluminum thick or thin?
Can you use Alumimark?
I think you need about 300 dpi or the dots will
overlap too much. If you can break the artwork
apart, make the gray a 40% gray.