Post processing for clear

General Discussion
1

Hi folks… did my first print in clear at 0.025 mm resolution and it looked really good coming off of the printer. I was optimistic that a little polishing with 1000 grit wet/dry paper was all I’d need.

By the time I cleaned and cured it had clouded up some though.

Q1: Any of you try water curing in the Form Cure? Would you recommend it? If I try this, should I use a glass or plastic container.

Q2: Any tips on polishing beyond wet/dry? I saw a Youtube clip where a guy used Turtle wax, but there’s only a thousand versions of that. :hushed:

I tried polishing with a felt wheel on a Drmmel and toothpast for compound… worked o.k., but the uneven and localized pressure actually dug into the surface some.

Q3: Do I need to get a buffing wheel? Any recommendations for polishing equipment?

2

A clear looking model direct from the printer cleaned with ISO will tend to still look somewhat clear - but when washed in water it will immediately start to look cloudy.

I have a drum polisher - but havent used it yet as I havent had a successful print at 25 microns.

3

Have you considered cerium oxide? I used to polish cast glass with this and it imparts a very high gloss - much better that with 3000 grit. You can order a slurry from Hisglassworks.com:
https://www.hisglassworks.com/polishing/3m-cerium-slurry-pre-mixed.html. They will be more than willing to discuss your application with their product. 800-914-7463

4

Here’s a pic of my best result so far…

  1. Orientation: I selected the face with recesses to be the final layer printed (bottom) as it is the hardest to finish. I put the flat face on the supports, knowing I can sand that on a granite surface plate very easily.

  2. Post Processing:

  • Washed in 99% IPA for 20 min.
  • Removed supports with snips to leave a bump rather than a dimple.
  • Cured for 30 min. in Form Cure to achieve full hardness.
  • Let sit for a day
  • Printed a sanding block to apply uniform pressure and ensure flat
  • Started with wet/dry using water and a touch of dish soap. 400-600-1,000
  • Switched to micro mesh, dry, 2,400 to 12,000 in seven steps.
  • Washed with soap and water.
  • One coat of Krylon gloss clear coat acrylic spray on each side

clear
clear916×1024 131 KB

Bottom right is my best effort so far
Bottom left is with no sanding or spray coat
Top is an injection molded styrene part for comparison.

1 Like
5

OBTW,

You can see the amber hue that the printed parts acquired while curing.

I tried water curing a part by placing it in a cut of 1 liter bottle of tap water in side the Form Cure and the part both warped and came out cloudy.

6

The clearest I have been able to get is by sun curing, avoiding the Form cure for clear resin. Just leave it outside in the sun for a few hours