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mike wallis
02-14-2019, 3:08 PM
Hello,
We have recently discovered that when Thermark is applied to Brass and left outside, the bond between the brass and Thermark breaks down as the surface tarnishes. See post below for images and details. I'm looking for a little more longevity out of the Thermark on brass and bronze when in the weather. My best guess is to apply a clear coat to protect it. Has anyone has any experience with coatings on bronze or brass? If so could you share your experiences? The brass and bronze would be either polished surfaces or matte. Or is there a another bonding material like Cermark, Laserbond 100 or Enduramark that offer more protection?

https://sawmillcreek.org/showthread.php?271925-Ever-Seen-This

Thank you for any feedback

Bill George
02-14-2019, 3:20 PM
From what I understand from reading on here in the past, no clear finish will last outside for more than a couple of years. If you want permanent you need to invest in a fiber laser.

mike wallis
02-14-2019, 5:07 PM
From what I understand from reading on here in the past, no clear finish will last outside for more than a couple of years. If you want permanent you need to invest in a fiber laser.

Thanks Bill for your reply. I did look into a fiber laser about 2 years ago but found that with the sizes we carry (12X12" and larger) the engraving time would not make in not cost effective. For a 12X18" stainless plate engraved with a fiber laser (Gantry) took around 3-4 hours from two of the manufactures we sent samples to. I would love to be proven wrong about this :)

Bill George
02-14-2019, 6:42 PM
Cost effective or not thatís the answer. A 30 watt or so Galvo with a 200 lens just guessing would cover 1/2 at a time. Gantry fiber is slow ask Tim.
Others may have a better answer for you. I am just going by my experience.

mike wallis
02-14-2019, 7:34 PM
Cost effective or not that’s the answer. A 30 watt or so Galvo with a 200 lens just guessing would cover 1/2 at a time. Gantry fiber is slow ask Tim.
Others may have a better answer for you. I am just going by my experience.

I looked into the Galvo systems as well but at the time you could only engrave smaller areas (I believe 12X12" max). Epilog has a newer galvo system (G2) that looks promising with a 24X24 area. However the last I checked with them it could not process bitmaps (their working on it).
I started this post a couple of years ago when looking into Fiber for larger panels. My take away from others post is it wasn't a good fit.
https://sawmillcreek.org/showthread.php?252962-Switching-from-Thermark-to-Fiber-Laser&highlight=

Tony Lenkic
02-14-2019, 8:43 PM
Mike,

Trotec has bigger galvo fibers> Take look at their Speed marker 700 and 1300 series.
I don't know what the cost is for either one of them but speed is awesome.

Kev Williams
02-15-2019, 1:05 AM
Almost every car on the road has clearcoat over the base color. Done right, clearcoat can last a long time outdoors.

Getting brass black with a fiber laser is as slow as stainless...

Paul Phillips
02-15-2019, 9:12 AM
There are some good industrial clear coats out there, I've had great longevity out of Cerakote Clear, expensive but when you just need to know it's going to last it's worth it.
https://www.clearcoating.com/products/#metals