If you're casting parts and your molds or cast surfaces come out with tool marks, micro ridges, or even slightly rough texture, there’s nothing more satisfying than turning them into near-optical clarity. I’ve been using the Dedeco Sunburst system to polish molds and cast surfaces, and it’s become one of the most reliably effective tools in my finishing arsenal.
What Is It (In Plain Terms)
The Sunburst system uses radial bristle discs, points, and polishing bits made of a thermoplastic material impregnated with ceramic abrasive grains. The bristles flex, adapt, and polish without aggressively gouging — which means you can get a very smooth finish without destroying fine details. Dedeco’s marketing says the three-dimensional bristle design delivers uniform finishing. RioGrande
These are great for working in tight radii, removing light tool marks, and getting to a polish without switching to heavy buffing wheels. They also run cooler and generate less dust than many conventional abrasives. Dedeco+1
How I Use It for Optical Clarity in Molds & Castings
Initial smoothing / blending
After demolding, I often see faint lines or texture from the mold surface. I’ll start with a medium-grit Sunburst radial disc on a slow speed, lightly brushing over those ridges to reduce their amplitude. The flexibility of the bristles means I can maintain surface evenness without introducing new low spots.Fine polishing & smoothing
Once the surface is roughly uniform, I move through finer radial bits (or stacking multiple discs) to gradually smooth. The goal is to remove microscopic tool lines and transitions so that the surface begins to catch light more uniformly.Final polish / gloss stage
In many cases, the Sunburst system alone can push the finish to very high clarity, especially on transparent or semi-transparent materials. If you want to push further, you could finish with a micro-abrasive or a polishing compound, but I often skip that step because the Sunburst bits do so much already.Spot touch-ups & tight features
For mold corners, grooves, or tight curves, I use the smaller points or radial bits instead of discs. They let me polish edges without damaging adjacent surfaces.
Through this workflow, I’ve taken cast parts from “slightly rough” to “looks almost molded glass” without a ton of extra steps.
Pros & Things to Watch Out For (Because I care that you don’t screw this up)
What works well:
The adaptability of the bristles lets you polish freeform shapes without flattening them.
Less heat and dust than rigid abrasives.
Good life and durability when used properly (i.e. light pressure, tips of bristles).
You can stack multiple discs to widen coverage or go deeper when needed.
What to watch for:
Don’t press too hard: you’ll burn or deform delicate features.
Speed matters: too high RPM can heat up and reduce effectiveness. Dedeco’s data shows their radial discs operate in wide speed ranges, but control matters. Dedeco
Always clean between grit stages to avoid cross-scratching.
Use appropriate mounts/mandrels so the bristles are properly supported.
The Results
In my hands, I’ve reliably converted mold surfaces with visible tool marks into casts with uniform, high clarity surfaces that require minimal further touch. On optical clarity plastics (e.g. acrylics, clear resins), the difference is immediately visible: light passes smoothly, no stray scratches catch the eye, and the overall look is “finished,” not “just molded.”
If you’re casting parts and want to avoid that “plastic haze” or visible striations on the interior of your molds, the Sunburst thermoplastic radial system is one of the few tools I’d nominate as essential.
