Engraving Cast Acrylic

[Rose Hamacher]

Larry,

So you think if I wipe really fast and don't linger that the acetone will be okay? How about if I wipe with the acetone and then use the Novus 1 to clean any acetone residue off? My arm was just really getting tired of the Novus 2 - it worked, but not without some serious scrubbing. That's why I was so happy when I tried the fingernail polish remover! No effort. I knew it was too good to be true. Ha. But, my bottle does say it is 'fast and gentle' and has vitamin E and Aloe . . . I may have to risk using it. . .wiping really, really fast.

Regards,
Rose

[Frank Corker]

Rose, I've been using my wife's nail polish remover for a long time on acrylic. I've never yet had any crazing or cracking.

[Kim Uleberg]

Disregard my last post in this topic....hadn't read it properly :-)

We're having this problem too...about the residue, we usually wash it with industrial alcohol, thats what we wash all our signs with when we paint them. But we've never had this problem before...washing off the residue is fine, but afterwards it cracks alot! We tried with nail polish remover just before, and it cracked just as bad. This has never happend to us before, and we can't figure out why it happened now...the residue is easily fixed by using application foil on the area you engrave. But we paint the engraved area, and then to get the paint residue off we have to wash with something...we have always used alcohol, but now it has a tendency to crack...very strange, also that this has never been an issue before...

[Mike Null]

Even though this thread deals with cast acrylic I'll relate my experience of today. I was engraving a pricey (for plastic) jewelry box today with a 7 letter name and a 50 point font.

I had engraved it a 600 dpi and a little slower speed than normal because I was looking to do a really neat job. When I took it out of the laser I realized it was extruded plastic. By the time I started to polish it with Novus 1 it began to craze and in a minute all the text was badly crazed.

Since the box was ruined I engraved the same name again using just an outline and again using 20% less power and a little more speed. Both of these were ok.

My thought is that the settings and depth (1/32") that I first used caused more stressing of the heat formed extruded acrylic material thus the crazing.

Anyway I'll be doing another one tomorrow.

[Larry Bratton]

Rose:
Use at your own risk. Corker says his works, but who knows, that UK nailpolish might be more polite than ours.

[Larry Bratton]

All:
I was recently posting a thread in EE about the use of Krylon Fusion paint on acrylic. I have been using that stuff on acrylics without any problem at all. Now understand, that paint contains some pretty nasty chemicals such a tolulene and the like. One of the members in EE said he tested on acrylic and it crazed it immediately. I went and painted more pieces just to test and I still saw no evidence of crazing from the paint. Go figure.

Is it possible that higher end acrylics such as those purchased from a commercial supplier opposed to the ones that come from Home Depot and the like are not as prone to crazing? I have also noticed that laser cut extruded is more prone to crazing than cast just by cutting. Is it possible that it could vary from lot to lot from the same manufacturer?

I notice that acrylic mfgs usually recommend soap and water to clean it. I don't use alcohol for cleaning for fear of crazing. I am leary of Windex and avoid the type with ammonia in it. I usually just wipe it with one of those microfiber cloths and water. It just seems that their seems to be no real pattern as to what is going to cause it to craze. Maybe I'm just CRAZY!

[Darryl Hazen]

Krylon Fusion paint is formulated to mildly attack the surface of plastics so it will adhere to the plastic better.

[Scott Shepherd]

Larry, I have personally had that happen to me with Black Fusion paint. I posted it somewhere on here, but to repeat, I cut out a rectangle with the laser, peeled off one side of the paper, painted it with Fusion, two coats. Engraved the signs, peeled off the front paper, and noticed all the edges were crazed quite heavily.

Went back to normal black Krylon, did the same job, same material, no crazing at all.

It's all Acrylite material. Extruded.

[Larry Bratton]

Larry, I have personally had that happen to me with Black Fusion paint. I posted it somewhere on here, but to repeat, I cut out a rectangle with the laser, peeled off one side of the paper, painted it with Fusion, two coats. Engraved the signs, peeled off the front paper, and noticed all the edges were crazed quite heavily.

Went back to normal black Krylon, did the same job, same material, no crazing at all.

It's all Acrylite material. Extruded.

Scott-mysterious stuff. I painted this I tested the other day with red. I wonder if the chemical composition varies from color to color? I have also used some Rustoleum Metallic Gold which turned out beautifully. No crazing with it at all and the color is beautiful. Much better than Krylon's gold. Guess it's best to test. Problem is that sometimes it won't craze immediately.

[Scott Shepherd]

Larry, according to the MSDS, here's the break down sorted by Parts Per Million :

Krylon (Normal- Black) :

Propane
Butane
Ethylbenzene
Xylene
Acetone
Methyl Ethyl Ketone
1-Methoxy-2-Propanol Acetate
Carbon Black

Krylon Fusion Black :

Propane
Butane
V.M.&P. Naphtha
Toluene
Ethylbenzene
Xylene
Acetone
1-Methoxy-2-Propanol Acetate
Bis (2-ethylhexyl) Phthalate
Calcium Carbonate
Carbon Black

My uneducated guess is it's the Naphtha that causes it. No reasoning to back that up because I couldn't tell you anything about any of the items listed

[Larry Bratton]

Larry, according to the MSDS, here's the break down sorted by Parts Per Million :

Krylon (Normal- Black) :

Propane
Butane
Ethylbenzene
Xylene
Acetone
Methyl Ethyl Ketone
1-Methoxy-2-Propanol Acetate
Carbon Black

Krylon Fusion Black :

Propane
Butane
V.M.&P. Naphtha
Toluene
Ethylbenzene
Xylene
Acetone
1-Methoxy-2-Propanol Acetate
Bis (2-ethylhexyl) Phthalate
Calcium Carbonate
Carbon Black

My uneducated guess is it's the Naphtha that causes it. No reasoning to back that up because I couldn't tell you anything about any of the items listed

Somebody said it was the toluene. I looked up the info too and I believe the red was 15% tolulene but again, I had no ill effects from it. I also see Acetone in both of them. Naphtha is plain old lighter fluid isn't it?