Finishing Plastics and Resins

Finishing:

Most resins and plastics can be shaped and finished similarly to metal.

Epoxy resins are the softest resin and I don’t recommend doing much with them post-pour. Due to the softer surface, even with the best precautions, the surface will not be as shiny as it is when it has been left alone. If finishing is required on epoxy resins, I recommend doing the finishing, and then recoating the top or affected areas with another thin layer of epoxy.

Polyurethane resins are much harder and can have quite a bit of work done to them post-pour.

To file:

Use a coarser cut file since the resin filings will tend to clog finer cut files. Wax working files are also useful for filing resin. Make sure to either use files that you have specifically designated for resin work, or clean the files extremely well afterwards. Using files designated for resin is the best option as then you don’t need to worry about getting metal shaving in your resin or resin shavings in your wax.

To drill/bur:

Make sure to go slowly and to keep the drill bit and/or burs cool. If the burs get hot, they melt the plastic, which does damage both to the bur and to your piece.

To sand:

Work wet. Either under running water, or by dipping the piece repeatedly and often into water. Water helps to remove any grit, dirt, and debris as it come off the piece so that it doesn’t get imbedded into the plastic giving it a cloudy look.

The Spectrum sandpapers are great for working with resins, as they are an open mash rather than a coated sheet and move the debris away quicker.

To polish:

Zam is the best compound to polish plastics with. There are several other products out there that aren’t a rouge-like compound that work, but in my opinion ZAM works the best.

Zam is used just like any other compound on the polishing machine. Wheels should be designated as Zam/plastics only.

You can also sandblast polyurethane plastics.