"Masking" Out Fine Lines for Paint - Looking for Advice

I am trying to make a meter dial for a piece of vintage electronics equipment I am restoring. The challenge boils down to painting fine lines onto a metal plate, itself spray-painted white. I thought I’d put down a layer of masking tape over the entire surface, use the GF to laser away the masking where the design will be, spray paint my desired color, and remove the tape.

Here are some photos of the result. The yellow (spray paint) and green (acrylic paint) will be acceptable after a little touchup. The red (spray paint) is a mess.

The topmost scale is not painted at all, only etched into the white paint.

I see at least three problems I’m having:

  1. The paint is bleeding under the masking tape.
  2. The masking tape lifts off dried paint as it is removed.
  3. The paint isn’t completely filling the area of the design, as in the 14 and 16 on the bottom right.

I think I can mitigate #1 by using very light layers instead of one thick paint layer. This might help with #2 as well. Dialing in the laser settings might fix #3.

But before I waste more time chasing this strategy, I thought I’d ask here whether any of you have been able to do this kind of thing successfully, and if so, how?

Another strategy is to use a masking liquid (a.k.a. masking film), but that requires another trip to the hardware store, and I have my doubts about how well it will work in this application.

I have achieved similar things in the past in acrylic using acrylic paints by scoring or engraving the lines and then filling the etched lines with paint. What makes it easy is the ability to easily remove excess paint by just scraping/squeegeeing over the line. With a thick enough white base coat I might be able to do that here, too.

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If you spray some acrylic ‘before’ you spray paint it might help to seal the edges-then spray very lightly many times. You may want to use a heartier mask than the beige masking tape. Painters tape seems to work better for me…

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Have you tried lightly pressing the tape down after etching? Or burnishing it prior to etching?

I usually remove masking tape while paint is still wet, to prevent the lifting. It’s trickier, and gets your fingers messier, but for some paints it seems to be the only solution.

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Can’t help with the three color but I was able to get great 2 color detail using 2 color acrylic and other 2 color plastic material. Think I got it from Rowmark but there are other distributers too.

A couple years ago I made a working Astrolabe with very fine numeric and line detail on the GF using such material.


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I have been meaning to post this earlier. I found this very helpful video.

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I have had success with infilling, and I do have some two-color acrylic. BUT, in this case I am working with a flat piece of metal. There is no real depth to the engrave. I could try to put down a layer of paint thick enough to create some depth. That might make it work.

This is always good practice with spray paints.

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It also looks like the paint hadn’t dried yet before you removed the masking and it seems to have smeared. I would definitely try more of a painters tape, and be sure it is light coats that are completely dry before removing it very carefully.

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Really weird idea, but hey it might work? Instead of using masking tape, try painting with a washable acrylic paint as masking, like craft paint. Then engrave, spray paint (hard lacquer paint), and when dry see if you can soak and float off the craft paint masking. Worth testing out to see if the technique works :wink:

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Or the reverse - Paint the solid colors, then paint over them with white, then blast through the white with an engrave to reveal the colors.

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Your :glowforge: is only burning off the masking tape and creating a mask for your paint.

@rljacobson, have you considered chemical electro etching your plate after scoring your gauge design onto the masking to give depth and traction to the paint. It is not that difficult and the results are pro. All you need is salt water and and a 9 V battery.

consider a few links:

Chemical Electro-etching

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