Dissolving filler or paint mask material?

[N2darkness]

I'm trying to figure out a way to mask the engraving in this 3D printed ring so that the main body can be painted and then the lettering exposed so it will glow.

I plan on cutting a channel on the bottom wide enough for some orange EL wire to be inserted and then puttied over.

I'm just trying to think of what material I can put into the inscription, level or sand smooth and them prime, paint and then remove so the translucent material would be visible.

The lettering is much too small to try and paint around by hand.

Here is the model in question. Trying to make a diorama of the ring sitting on the lava bed before being destroyed.

 

[AnubisGuard]

Wax, maybe? Rub it into the grooves, paint, then heat it up so the wax melts off.

 

[N2darkness]

Wax, maybe? Rub it into the grooves, paint, then heat it up so the wax melts off.

I thought about that, but is also a resist for paint and have to make sure it is removed from anywhere I want paint to stick.

I've also thought about making a powdered sugar mixture and then let it dry and dissolve later, or something like toothpaste and paint over and then wash off.

I think a lot of tests will be involved, but checking if someone has already done something like this before.

 

[Mach]

You might try salt instead of sugar. A very fine popcorn salt could work. I've done salt chipping on models before but not exactly what you are trying to do. I'd try the following - wet the letters with water then dust in the salt, let dry and gently sand. Given the curvature, you'll have to go in sections.

Looking further afield, PVB filament or polysmooth is alcohol soluble. As long as you are painting with a paint that is not dissolved with alcohol, you could make a slurry then paint it into the letters, sand and then topcoat. Follow-up with a soak in 90% IPA. Similarly, PVA or elmer's glue is water soluble.

 

[PB Props]

I've done something similar to this many times in the past. A little bit like the wax suggestion above, but a lot easier.

Get some sulphur free plastiline clay, warm it up through a bit of kneading, then smoosh it over your text and really press it in. Scrape away the excess and then smooth it out with mineral spirits on a brush, then with a decent rag - also soaked in spirits, which will cut through it like butter.

Prime and spray as you would normally and allow that to cure. Once done. you can go back in with a cocktail stick and pick out the clay, then clean it up with mineral spirits on a hog hair brush. Just make sure that your paint isn't enamel based as it too would come off.

You can try variations of this, IPA cuts through acrylic paint, mineral spirits cut through enamel. You could even use one type of paint to fill the text, paint the entire ring with the other type, then come back in with your solvent and pull out the text fill in paint with the appropriate solvent. I still think clay masking is less risky though.