Clouding or fogging when engraving on PG Medium Clear acrylic

Trying what I thought was going to be an easy GF project—making table numbers for school event by engraving and cutting PG medium acrylic to be put in an LED base. Used the manual settings. First try with masking on, did not even go through the masking, no engraving. See image on left. 2nd attempt— took masking off the top and I got a cloudy residue around the numbers, not easily removed. I can live with the lines in the engraving but not the overspray look. () Any ideas/settings to avoid this?

Screen Shot 2020-02-06 at 12.16.46 PM

I can almost guarantee that you took a look at the settings and accidentally reset them to manual mode (which defaults to full speed, negligible power)
Go back to the default settings for acrylic and give it another shot. Acrylic is standardized so even if you weren’t using PG acrylic you should still try the PG settings

I’m guessing the “overspray” effect you’re getting is something on the masking. You can try cleaning it with toothpaste (paste, not gel) or a dozen types of acrylic cleaner (you can do a search on here for suggestions) (don’t use alcohol, it’ll mess with the acrylic) but it’s definitely not something that is normal or expected.


The power of 1 is not correct as you obviously know. I would leave the masking on and defocus. I think a second pass a lower power would clean up the residue. Remove the masking and you should be good to go. Use the Proofgrade settings.


Not sure how the settings got changed? How do you reset them?

Hi and welcome to the forum. I had a similar issue a couple of times too… I don’t know if this is the same root problem, but I notice that your power is 1.

The issue I had, especially if I was on manual settings, is that if I hit the < arrow to go back, it would reset my settings to default of 1 which doesn’t seem to be powerful enough to do anything. But if I click on the bed preview to hide the pop out, then my settings save. I can’t remember what settings I’ve been using for acrylic [I keep a log, but it is on another computer] but it was based on the PG Acrylic.

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You can choose the medium clear acrylic in the materials drop down. When you select engrave for the numbers, you should get to choose SD engrave, HD engrave or graphic engrave. SD engrave is 1000 speed, full power, 270 lpi.

Thank you! Will try that.

Likely what happened. Thanks for the tip ; /

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Looks fab! Thank you so much!!! Love that I can keep masking on and finger prints off until night of event. Still some lines in numbers though. I tried defocusing at .225, should I play with that to get rid of the lines? There really should be a reset setting button. Thanks again for the quick response!

Worked great with masking on and settings of SD, 1000, Full power, 270dpi, and defocus .225 for clouding, but still have a few lines in numbers engrave. Thanks!!

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Glad it is working better. You might need to play with the defocus amount and/or lpi until you get the look you like.

Some people experiment with floating a little acetone or even UV or epoxy resin in the engraved areas to even out the striations.

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That is vaporized acrylic depositing on the unmarked surface and permanently etching it, like a chemical process. You can scrub it away but on a clear piece like this, it will never give you a perfectly clear surface. There are products specifically designed for this, but I think we would rather avoid it to begin with than have to purchase more chemicals to fix it.

I’ve been doing a lot of testing of this lately, initiated by “common knowledge” that alcohol causes problems (it doesn’t.)

It’s generally been accepted that removing the masking is ideal for detailed engraving, but to prevent this type of problem, it needs to be left in place. Your first issue was one of incorrect settings, as covered above. The default SD engrave will blow through the masking for solid areas (but not for light detail in photos).

The other issue, which you don’t bring up, is the “banding” across the engrave. Again, something we have ways to “fix” (defocused second pass) but we shouldn’t have to.

Try .5 or .495


I have run a few PG acrylic pieces without the masking and have had this fogging as a result. I have found some light polishing compound to work very nicely to remove this residue. I would not describe this effect as a permanent etching at all. Meguiars No.7 or Meguiars 205 polishing compounds have produced a renewed perfectly clear surface restoration for me with very little elbow grease. I would speculate that most car polishing compounds for swirl remover and such would provide excellent results for surface restoration. Masking is great when you have it on acrylic, but you can have some great results with just a little after-work if you have this “overspray” look happen to you.


Thanks for the answer @dklgood, that’s right. I’m going to close this thread - if the problem reoccurs, go ahead and post a new topic, or you can send us a help request at Thanks for letting us know about this!