Post processing for clear


#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

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.


#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