View Full Version : Acrylic: Can I engrave through protective masking?

Ross Moshinsky
11-07-2018, 9:35 PM
I have a decent sized acrylic panel to engrave and color fill. The paper masking I have is few inches short. I could seam it, but in my experience that shows up. There are no big "gaps" in the text to strategically put a seam either.

Anyone have any positive experience engraving through the stock protective masking? This acrylic happens to be what I believe is Chinese acrylic (not Chemcast like I normally get) and the masking seems thinner as a result. I'm hoping I can engrave through the masking and paint fill after.

Joe Pelonio
11-07-2018, 10:04 PM
If it’s just text, I use transfer tape rather than the original paper, and before engraving, vector cut with low power, and weed out the letters. The engraving will be nice and clean for the paint fill and the overlap won’t matter. That original protective film melts and smears when engraving, but it cuts nicely.

Kev Williams
11-11-2018, 1:33 PM
Laser engraving or ENGRAVING engraving? If tool engraving, don't bother with masking-

If laser engraving, I've had good luck with lasering thru transfer tape, then spray-painting afterward. But adding bottled paint, not so much, too much bleed...

I make a lot of plex parts that are engraved then painted. Best overall options I've found: If possible (think time and tedious-ness) use a needle-tip bottle to fill the engraving.

If you're talking a ton of engraving, go to Home Depot, get a half-pint or two of Rustoleum gloss black enamel, and, if you don't already have something similar, pick up some Bondo squeegees. Put some DNA in some sort of bottle you can dispense in small amounts from...

Also needed is some old (or new) cotton bed sheets, and something resembling a sanding block. I have a few 1" thick plex blocks cut to about 2-1/2" x 6", with all sharp edges slightly rounded off. Actual sanding blocks usually have a felt pad, wihich is counterproductive...

The process is simple: pour some paint on, squeegee it into the engraving, swiping as much paint off as possible, repeat until finished. Let the paint dry.

The cotton sheets need to be cut to square foot or so size (to start, adjust to your preference) Wrap the sheet around the sanding block and pull as tight as possible with your hands. Wet the sheet somewhat with DNA, and scrub off the excess paint. The sheet will load up with paint quickly so you'll need to move to a clean piece of sheet often. Repeat until done. The cotton sheet and block is great for cleaning excess paint and not bothering the paint in the engraving. If the streaks don't want to come off so easy, switch to mineral spirits, but be aware that the fumes can soften the engraving paint pretty quick. If the engraving is deep, usually not a problem. And I've never had problems with clean squeegees or cotton sheets scratching.

Back to masking--- I was just thinking, that I've been getting a lot of stainless lately that's been laser cut, and masked with plastic-y masking called NOVACEL, it seems to leave nice edges even after being cut with high-powered lasers. The pieces I get need words in a few places, and rather than peel the whole panel I cut rectangles around what I'm to engrave using low power (like 20%, 40% speed w/30w GCC), then I remove the rectangle to apply Cermark. I've never tried engraving thru this stuff since it's always been applied to stainless, but I have to wonder how will it might work on plex to engrave thru? Only issue is that it's a little on the thick side, seems to be 2-3 mils... Have no idea where to get it or if it comes thinner...

Ross Moshinsky
11-13-2018, 2:30 PM
To fill in: The masking laser engraves through fine. Modern Masters paint is a genuinely horrible product. I don't know why I tried it again on this project. Stuff simply doesn't like adhering and it's elastic as hell.

Lucky for me I can flip the panel over and re-engrave. Unlucky for me is that's 2+ hours of my life wasted. Oh well.

On projects like this, I actually combine ideas. I keep the masking on but use a squeegee to fill with paint. I find it to be the best compromise.