Polishing resin is a relatively simple process that just takes a little patience and effort. This Instructable will address how to polish resin to a high gloss, focusing specifically on how to polish a resin part made from a 3D printer. The same methods I will address in this how-to, apply to all cast resin polishing, and can be used to polish virtually any type of resin be it polyester or epoxy based.
The method first starts with some good old fashioned detail sanding working up through the grits, from very rough, to a very fine wet sanding. Then we move into two different grits of polishing compounds, and finally finish everything off at the buffing wheel using two very fine polishing abrasives, and finally, a carnuba wax polish to buff everything to a bright shine.
When done correctly, well polished resin casts and parts look absolutely amazing, and are works of art, ready for display, jewelry and enjoyment in and of themselves.
Before I get too far into things, let me just tell you a little bit about the part that we'll be polishing. A few of us at Instructables have been working with a lab at UC Davis to do some test prints of 3D models that they've been developing to better understand how and why race horses break their bones. This Instructable focuses only on how to polish these kinds of models. There will be a much larger Instructable about the entire research project coming along soon.
The particular model featured in the photos in this Instructable is a horse's leg muscle that's been scanned and modeled to show how tendon attaches to the end of a horses muscle. Tendons are modeled in white, while muscle tissue is represented in clear. While casting a resin part like this would be extremely difficult, and realistically speaking, virtually impossible, our Object 3D printers can produce a resin print like this a matter of hours.
I've been excited to work with the researchers at UC Davis because I find this kind of 3D printing really compelling when it comes to showing off the kind of work that we're capable of producing with this new technology. There's obviously a whole lot to be explored with 3D printing, but representing complex biological models to advance medical research is one of the more compelling applications.
In any case, if you've ever wondered how to make resin shiny, read on.
Step 1: Clean 3D Print or Cast Part
3D prints come out of our Objet 3D printers covered in support material. The support material is a waste product of the print and must first be cleaned off before polishing can begin. Use a pressure washer, surform tools, dental tools or whatever you have at your disposal to properly clean the 3D print. If you are polishing a cast resin part, clean the outside of the resin with soap and water to remove any mold release that may be on the part.
Depending on how the part was cast or printed, it may or may not have a rough surface. For the purposes of this Instructable, we are going to assume that the part has a rough surface, since the steps in polishing something that is rough are the most comprehensive and encompass the steps for simply polishing something that is already smooth.
If your surface is already smooth, it's possible to skip some of the first few steps that are a part of this Instructable.