Epilog Laser Legend 6000 Owner's Manual page 55

Owner's Manual for EPILOG Legend Model 6000
December, 2000
Finally, a paint coating is applied on top of the lacquer for the finished product. When laser engraving brass-
coated steel, you are removing only the paint and exposing the polished brass coating that is protected by the
lacquer. The lacquer prevents the brass from oxidizing and the bright reflective surface will stay bright for
years.
The other two types of engraving brass are solid brass that either can or cannot be acceptable for laser
engraving. Some manufacturers will polish the brass before applying the paint coating and some will not. If
the brass is polished before the paint is applied you will have a nice reflective engraved surface. If the brass
is not polished, the result will be a dull, tarnished brass that will require a secondary polishing process after
laser engraving. This is time consuming and most engravers do not want to spend the time and effort
necessary to turn this into an acceptable product.
If you are unsure if the piece that you have is brass or brass-coated steel, you can test the material with a
magnet. A magnet will stick readily to brass-coated steel, but since solid brass is not magnetic, a magnet will
fall helplessly away from solid brass.
BRASS ENGRAVING TECHNIQUES
Engrave painted brass at high speed and low power. It takes very little power to remove the paint coating and
too much power will melt the paint and distort the image. If you are producing engraving that appears to be
"fat" or has a balloon appearance to it, you are probably using too much power. Reducing the power will
bring back the nice sharp images that are normally produced with painted brass.
It is possible to laser bare, un-coated brass and apply an oxidizing agent to the engraved area to produce a
black image. This process is the same as the process used when rotary engraving brass and using an oxidizing
agent. Be sure that you are using brass that does not have a lacquer coating. The laser has a very difficult
time adequately removing the lacquer coating and the oxidizing agent must react with the bare brass in order
to work properly. You will need to experiment to ensure that the brass that you are using can be oxidized
after laser engraving as it can be difficult to determine if there is a lacquer coating over bare brass.
NOTE* - Use caution when trying to engrave brass coated pens. Many pens have a very hard epoxy paint
that is completely unacceptable for CO2 laser engraving. The results are a tarnished, brown looking finish
that cannot be corrected. You should only use pens that you have experimented with or that are specifically
designed for CO2 laser engraving. Be aware that there are many pens that can be laser engraved with a YAG
laser but these pens are usually not compatible with the CO2 laser that you are using.
Use caution when trying to engrave blue painted brass. Blue paints contain very aggressive pigments that
penetrate the metal surface and it can be extremely difficult to remove all of the blue color. Some
manufacturers will use black paint as a base coat before applying the blue paint and this process produces a
product that is acceptable for laser engraving.
Section 10 – Engraving Techniques 51