Wooden plaques

[Jeff Wilkins]

I just finished a run of plaques for my school yesterday and was getting some contrast with Poplar but not as much as I would like. The wood was donated to our program, we planed it, cut to size, and routered the edges to make 5x7 plaques.
Lasered at 500 dpi, 80 speed, 80 power on our 60W Spirit GX and put a coat of clear water based urethane on it. Any recommendations would be great to improve contrast. We have tried different speeds and powers. It seems we could slow the laser down and reduce the power a bit to get a darker image. It took about 5 mins / plaque to laser. Is that "normal" for a 60W machine. What would these retail for? Thanks I will try to add a photo later

[Tim Bateson]

Throw it out of focus 7-10 clicks.

[Martin Boekers]

This is something that JDS is now selling, I may try a can since I have similar issues with Maple. It improve Oak too.

http://php.jdsindustries.com/JDS_WEBSITE/TEST/check_qty.php?ITEM=LDK201&TRUE=TRUE

http://www.laserdark.com/

I found if I run a second pass a bit quicker it helps.

[Chad Fitzgerald]

hey jeff, white woods are tuff to get contrast. paplar, basswood, baltic birch, etc. slowing it down will help, along with lower power. just takes longer. you can also run it a little out of focus, that can help as well. have to play with that some to get what you want.
what i like to do is finish the piece first, then engrave it, crank up the speed so you just get through the finish, then you can wipe stain over the engraving and wipe it off. as long as you have a decent finish it will wipe off where it is not engraved. one thing to be careful of is that the stain can wick from the engraved area under the finish which looks ugly. to help with that i keep old cans of stain where the "sludge has settled, i pour off most the liquid. then i dab the rag into the "sludge", its thicker so is less likely to wick under the finish. some people will use shoe polish.
The key is to have a decent finish on the plaque first.
Since the poplar was donated to school, your likely stuck with it. whenever possible i like using alder, cherry, brown cedar works real nice, red cedar does as well but the white in it doesnt darken.
Hope this helps
chad

[Joe Hillmann]

To get contrast you could use an oil based polyurethane before you engrave it (I use minwax for floors) It will turn the plaque a golden color, then do your engraving and your white engraving on a golden plaque will have quite a bit of contrast. The problem with this method it the oil based finish will take at least five hours to dry in the best of conditions.

You could also use Chads idea, but as he says your color fill can wick into the grain under the finish. When I do color filing on wood I often use scuff cover (sold next to shoe polish) of everything I have tried for color fill I have found it the least likely to wick outside of the engraved area.

[Mike Chance in Iowa]

+1 for what Tim said. I use Poplar for test engravings when I'm working with photos or fill patterns. I'm not worried about the contrast in the tests, I'm concerned about how the engraving looks and that can be easily viewed when you tilt the wood. The darkest engraving I have ever achieved on Poplar was when I forgot to focus and was about 7-10 clicks down. Of course, if you are engraving something with fine detail, this option may not work so well for you.

[Dee Gallo]

You can also use a coat of paint and laser through it. I've seen some amazing results with black undercoating and white overcoating which obviously hides the wood, but is another option for you to get some dark lines on a white surface. Here is an example done by Jim Puentes who made a marble background for these portraits on plain old pine. I think it's an outstanding yet simple technique with lots of potential.

cheers, dee

[Chuck Stone]

wow, Dee.. that looks great! I'd have thought it was marble.
I do some engraving on paint too, but usually the reverse.
(white undercoat, black topcoat.. engrave back to white)
I'm going to have to try this now!

Another thing that might help the color bleed is to save your
acrylic scraps. Throw them in a glass jar with acetone. When
it turns to syrup, add more acetone to get a thin consistency
and 'paint' that onto the wood first. It permeates the wood
with acrylic, so there's little or no color bleed. And you can
laser through it once dry. (dries quickly as the acetone flashes off)
Fill with paint, wipe off. You can also sand it back after the paint
is dry. And since it is clear, it tends to keep the lighter wood's color.

[Guy Hilliard]

The easyist way I have found to improve the contrast on a finished wood plaque that has already been engraved is to go over the engraving with some black liquid shoe polish. Use a paper towel dampened with a little glass cleaner to clean up the surface afterwards. Works like magic with no "bleed".

[Bill Cunningham]

The easyist way I have found to improve the contrast on a finished wood plaque that has already been engraved is to go over the engraving with some black liquid shoe polish. Use a paper towel dampened with a little glass cleaner to clean up the surface afterwards. Works like magic with no "bleed".

Yup.. I've done the same thing with dark brown liquid polish. If you let it soak into the engraving for 5-10 seconds, you can wipe it right off.. If the finish is good, it comes right off the surface even on oak.