View Full Version : Settings to engrave away the paint on back of clear acrylic?

Emma austin
07-06-2011, 3:49 AM
Not sure the sort, but it is the type that goes white frosted if I engraved straight on to it.
Have painted the back and want to try engraving away just the paint, then colour again.
Should I mask the painted area first? Guess I would need to to keep the paint from going on it in the next colour huh?
No idea what settings to use
I have a 50 watt.


Rodne Gold
07-06-2011, 4:14 AM
Try 100% speed and 30-40% power. You need to go a little deeper than just frosting for colour fill. No need to mask if multiple colour filling , just don't get the paint in the other parts you want to fill with a different colour (or mask if they close together)
Best way to fine tune settings is use a test piece and see.....

Emma austin
07-06-2011, 4:23 AM
Thanks Rodney,
Yes this is all practice I am only trying it because I have seen it done on here :)

Dan Hintz
07-06-2011, 5:50 AM
The only time I worry about masking for stuff like that is when my fine motor skills (or the huge spraycan nozzle) doesn't allow me to control the overspray... otherwise, it's usually enough to lay down a piece of cardboard with large holes cut out for each color.

Mike Null
07-06-2011, 5:58 AM
I usually engrave to a depth of .030" or a little less than 1 mm. If you're doing multiple colors a low tack mask or a shield may be necessary to avoid putting the wrong color into an area.

Scott Challoner
07-06-2011, 10:24 AM
Maybe I'm not reading your original post corectly, but it sounds like you're doing reverse engraving. I do a fair amount of these.
It's reverse engravable material. I engrave the top text and paint it red. After it dries, I put it back on the machine and engrave the rest and paint the whole thing black. In your case, you have already painted the base coat so no masking would be necessary for subsequent fills. One thing I have experienced though, is that cast acrylic is difficult to reverse engrave due to the frosting effect. It tends to mute the color behind it. I usually lower the table about 2,5mm to smooth out the engraving. Hope this helps.

Mike Null
07-06-2011, 10:44 AM
I engrave the whole thing at once but mask part of it for the first coat then spray the whole thing.

Dan Hintz
07-06-2011, 11:37 AM
I engrave the whole thing at once but mask part of it for the first coat then spray the whole thing.
Yeppers... doing it in two steps adds unnecessary time.

Scott Challoner
07-06-2011, 3:03 PM
Yeppers... doing it in two steps adds unnecessary time.
Only if you sit around watching the paint dry. :D Hopefully you have something else to do on the laser during drying time but it doesn't always work out that way does it? This method worked well when I was doing several signs using whole sheets of material. I'll admit, the last couple I did, I engraved everything, brushed on the red and sprayed the black. I used to use Krylon Fusion for the fill which dried quickly, but I started getting crazing in the larger engraved areas so I switched to Krylon H2O which takes forever to dry.

Emma austin
07-06-2011, 4:47 PM
Thanks guys. Scott that is a nice looking sign and yes basically what I am looking at. I think you are right though, the cast acrylic will make it difficult. As I know if I go deeper than the paint I will get the frosMted look on the letters, where as I imagine extruded means you can engrave deep and still be clear?
I imagine my plastics fabricator will have extruded, I only ever get cast as primarily my products need the nice frosted look!

Mike Null
07-06-2011, 6:04 PM
I don't use anything but cast. Such as this sign: http://www.sawmillcreek.org/showthread.php?168572-painted-acrylic-sign