The Substrate

For this project, I used what I believe to be ~6mm Hickory Veneer MDF that may be similar to this:

https://www.menards.com/main/building-materials/panel-products/hardwood-panels/1-4-x-4-x-8-a1-hickory-mdf-core-plywood/14x4x8a1hickoryps2s/p-1444445022617.htm

Prep The Surface

Smooth and Clean

First I lightly sanded the surface with 200 grit paper, blew off most of the residual dust with compressed air, and wiped down the surface with denatured alcohol and a microfiber cloth.

I prefer denatured alcohol as it evaporates fast enough not to leach the substrate but slow enough to be effective at helping collect the finest particulates. Make sure it's high quality and/or not just for fueling camping stoves as that stuff may have impurities.

Inspect and Tidy Up

I use gaffers tape to lift off any stubborn residue, trapped fibers from the cloth, etc...

Mask The Substrate

This will ultimately create a stencil so you can maintain sharp outlines when you color fill.

I lightly dust the substrate with air just prior to masking with medium tack application tape and squeegee very well. It seems to be okay if they overlap, just make sure you are set up to get some good depth with your engraving settings.

Here is the mask I use: https://uscutter.com/GreenStar-Layflat-Classic-Transfer-Tape-Medium-Tack-Assorted-Widths/

Engrave The Design

Next, I set up and run the job. Be easy on the air assist so you don't blow any masking loose or off. This article may or may not be expanded to include resources about the design file, settings, etc... For now, we will just assume your design is 'laser ready'.

Clean Up and Prep for Painting

I dusted it off with air and went over the remaining masking using some backing from some vinyl as a buffer sheet so you don't move or damage the mask. A roller could work for this too. 

The idea is to make sure there are no places where the masking has delaminated from the substrate. 

Apply Clear Coats

Once it has been prepped, I shoot 2 coats of clear to mitigate the bleeding of the fill paints into the substrate. Let each coat dry fully. 

HINT: I use the TL  Timer to turn on my fan and place the work in the laser to dry. This evacuates the fumes as it dries and accelerates the drying process.

Color Filling With an Airbrush

Equipment Used

Here is what I got for my airbrushing:

Master Airbrush Cool Runner II Airbrush Kit	Airbrush Cleaning Kit
LINK TO AIRBRUSH KIT	LINK TO CLEANING KIT

Prepare A Suitable Work Area

I use my Nova 35 for my workspace and again I turn the exhaust fan on with the tl timer so it will evacuate the fumes. Although when used correctly, the airbrush emits surprisingly little 'stray' particulates (especially when compared to a rattle can.)

Apply The Main Color

Black is applied first. This is my first ever attempt at using an airbrush :)

Apply The Secondary Color

Then the red

Remove The Masking

To remove the mask, I start pulling the largest, easiest pieces and then use high-pressure compressed air via an air nozzle with a small orifice to blow off as much as I can. Then I use gaffers tape and tweezers to remove the remaining mask.

NOTE: You typically want to remove the masking before the paint dries so it won't crack, etc... when removing the mask.

NOTE: if you find places where the paint got through the mask or otherwise bled onto the surface, you can sand it down back to the wood to mitigate that. Again, make sure you have enough engraving depth to not sand away the filled area(s).

Apply 2 More Clear Coats

Then I apply 2 more clear coats.

The Finished Project

Here is the finished project.  I will likely add a stain on future projects so the 'bare' surfaces will pop.