how to darken laser recesses?

[sir.orange]

I cut some writings into different veneers that will be used as top sheets for some clients skis.
To enhance the contrast (as promised to the customer...)i d like to colour the 3/10mm deep laser recesses black. I did some tests on veneers with slightly thicked black coloured epoxy, problem: i also filled the surounding porosities of the veneers, the spot was black all over.
The veneer won t be covered with a top sheet, there will only be wax or oil as a finsh layer.
I m thinking about to cover the whole veneer with a tape next time and spray the veneers after the laser.

the picture below is the test veneer in bamboo. the veneers i m goping to colour are olive and oak

[chrismp]

maybe you could use a soldering iron to slightly burn the surface of the wood.

[twizzstyle]

Off-topic: what kind of laser are you using? Is this a homebuilt rig, or something commercial?

I want to add a laser to my CNC router for this exact thing. The results look beautiful.

[sir.orange]

it s a commercial, local engraver here where i live. the results are really good, he made the suggestion to fill the poroties with grain filler and cover the veneer with a tape and laser then. afterwards i can spray or fill the recesses with coloured epoxy.

[Jekul]

Lasers can be a very fickle tool to work with. I have 5 years of moderate laser material processing under my belt, and every new application is very different.

What wavelength is the laser?
What power are you using?
Steady state laser or pulsed? If pulsed, what's the wavelength?
What can you change on the engraver?

It appears that the laser is actualy doing an excellent job! You get no burning or charring of the edges, which in my world is very nice
But, what you want is a less-than-ideal laser cutting process.

Here's what you can try:
1. Turn down the power and make several passes
2. If possible, lengthen your wavelength (200nm or more)
3. Defocus the laser beam
4. Go slower at a lower power

[Jekul]

Twizz -

I want to add a laser to my CNC router for this exact thing. The results look beautiful.

So many things to consider about lasers before just throwing one on your CNC...

if you're serious send me a PM and we can talk about your application, or possibly start a new thread so we don't hijack this one.

[PTTR]

Put on a thin layer of laquer, carve it, color it and sand or scrape the laquer of. Thats how you do it in traditional woodcarving.

[MontuckyMadman]

U need a resist layer. Wax or somthin like tape maybe then smear in some simple ink and remove resist layer around engraving.

[sir.orange]

the two words above are sprayed on the bamboo veneer that has been grain fillered only once on the side facing us.

the spots "handmade.." were grain fillered on both sides of the veneer (0,6mm thick) seems like you need to saturate the veneer completely, let it dry, put a covering tape, laser it, grain filler the lasered recesses again, then spray, let it dry and peel the tape off. result is very clear lines and no leakage of the colour into the wood grains.
i m just thinking about how to finish the wooden top-sheets on the skis... on the last skis i was using oils like used for wooden floors and stairs. i like ti have a natural look but also proetct the the veneer from moisture and stcking snow..

[Richuk]

wax ... paraffin wax will provide the most protection.

[gerryrig]

Bamboo is a very pourous wood so you need to seal the pours before you paint.
I would think you could apply your resist tape then laser, then seal the ingraving with laqure, then paint whatever color you want. The key is to get the wood sealed with something clear before you color. If you are going to use wood filler you should fill the entire top sheet or you may end up with blotches where you used filler. They may not show up untill the ski has been out in the elements a few times. Then you are stuck with an unrepairable ski.

[More]

multiple passes at lower powers works for me to get it a bit darker.not as dark as your filler photos above though.