Cloudy or frosted casting material?

Hi.

I’m looking to cast a few small translucent (not transparent/clear) parts that will be back lit. Currently my plan is to cast them with clear resin and sand the back of them, but I would prefer to cast them in a material that is inherently cloudy.

Does anyone have any suggestions?

Hate to dig a post as old as this up but I have exactly the same question that I can't seem to find the answer to.

I have already tried a variety of things that have produced varying results and wanted to prod y'all for suggestions..

I am creating custom tail lights back lit with an array of smd leds and have created the 3d shape of the desired lights and casted a clear epoxy resin with a red tint that is about .75 inches thick. I have tried sanding the front and back with varying grit sizes but have yet to achieve the level of diffusion I am looking for. Is there a way to cloud the resin to increase its ability to diffuse leds, perhaps by adding something like dust particles to scatter the light as it travels through the acrylic?

The best results achieved thus far are by using tons of hot glue over the leds in the shape of the light, however this is impractical at scale and was merely an attempt at a quick test solution that has been the results I have been trying for. I can post videos and pictures if needed

I achieved the best results by actually gluing very thin white polystyrene sheet cut in the shape I needed as diffusers. It worked exceptionally well with a very uniform light as a result. If the parts you are casting are large enough to accommodate sculpting then "light piping" or ridges for the light to bounce on will help spread the light even if it does not diffuse the light per se. Have you tried just adding more red pigment to make it more opaque? The other option is to paint a layer of white or red on the back of the clear part that should do a similar job as the thin styrene and leave a clear look when not lit. It might be harder to get a uniform layer of colour on though as compared to just gluing a piece of plastic to the back.

You could mix in a tiny bit of white pigment.. maybe even chalk or talc?

There are semi clear "clear " sprays that will yield a frosted effect. I rarely use them but if memory servers Krylon "clear" comes out frosted when sprayed on a clear item... usually the cheaper "clear coats" do this.

Jedi Dade

Here's some options:

1. TAP plastics sells various densities of translucent white acrylic that could do the trick. 1/16" should be fine.

2. Photography suppliers sell "diffusion paper" - which is really plastic sheet of various densities made specifically for diffusing light.

3. If there's room behind the lens, don't point the light source directly at the lens - instead, relocate the light source so that it shines on to a white "bounce card" which sends diffused light through the lens. Think of it like looking through the lens at a brightly lit white wall.

Could also try sand blasting the piece.

Wow, bunch of great ideas here. Thank you all, will report back

I know i'm late to this party and new around here (long time lurker)

I wanted to throw in my two cent, in the past I've "frosted" small bands around an acrylic pipe for the end of my Ghostbusters particle thrower by masking it off and brushing the pipe with a brass wire brush going evenly in two different directions, the result was surprisingly even and very professional looking.