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Masking removal

OK, I just received my order of a bunch of little daberdoos for Girl Scout camp. Being relatively new at getting plastic things made, it didn’t occur to me to ask that the top masking be removed. Whups! :confused:

Can you suggest an easy way to remove the masking off of a bunch of small acrylic items? The size and quantity of the pieces make it challenging enough, but I also had engraving done on the top so the masking paper is all chopped up into little pieces.

At the moment I have one soaking in water to see if that frees it up. Are there any better ideas?




Is it an option to have the girls peel their own parts? (Peeling one or two parts can be fun, but I know that it gets old very quickly!)

Please note that since your parts were vector-etched (not raster-engraved), we would have recommended leaving the masking on, anyway: vector etching is the same process as cutting through acrylic (except we turn down the laser power); if we remove the masking during cutting/etching, the laser leaves spray marks or hazy/misty marks on the surface of the plastic that are difficult to remove. For raster engraving, we normally remove the masking during engraving and re-mask it for cutting (rastering leaves only a little bit or no hazy/misty marks). Sometimes we leave the masking on during raster engraving if the customer wants to fill the engraving with paint. You can read a little more about the two engraving types at pololu.com/docs/0J24/4 .

We do not have much experience ourselves with efficient masking removal. We have heard about solvents for cases where the plastic is so old that the paper masking no longer peels off easily since the adhesive has become brittle and stuck to the plastic; perhaps these chemicals might also make removal of “fresh” masking easier. In all cases, you should always follow these general steps:

  1. Test on a small section first.
  2. Soak the piece in a well-ventilated area until the paper is soaked through (usually 10-20 min; some things are sprayed on, others are brushed on, others you can pour in a tub for full submersion).
  3. Remove the paper before the solvent dries out. Apply more solvent if needed. Wear protective gloves just in case.
  4. Oily residue left by solvents should be removed immediately by washing with warm, soapy water. Be careful not to scratch the acrylic (even paper towels can scratch acrylic if you press too hard).

Solvents to try with the above process:

  • silicone spray (probably available in a hardware store)
  • goo gone (probably available in a hardware store)
  • mask-off
  • eucalyptus oil
  • aliphatic naphtha
  • hexane
  • kerosene

To reiterate, the above steps and solvents are normally for removing old, stubbornly-stuck-on masking from acrylic, but they still might help in your case. Maybe they will make it trivial to slide off the little pieces of masking (be careful not to scratch the acrylic!). We have only tried the goo gone, which worked fine for removing old masking.

I hope this helps; best of luck, and if you figure out a good technique, we’d love to hear about it!

- Candice

This is a pretty helpful bunch of suggestions:
support.ponoko.com/entries/50939 … om-Acrylic