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White residue on print using MakerJuice G+

Hi gang,

My first print with the Titan was a success! Did not expect that. I printed the V-shaped test article at 50µ using MakerJuice G+. One question that I have is that there is a white residue between the fins. What is this and how can you remove it or prevent it? Here’s a photo:
New photo by Robert Blaske

thanks,
-Robert

The best way to get rid of the white residue is to scrub those areas with a cloth or q-tip as part of your IPA bath finishing, before you do any UV post-curing.

Exactly why it forms is a bit mysterious, it seem to vary depending on resin type and the shape of the feature. My best guess currently is that it is partially cured resin that mixes with water or alcohol (becoming slightly dilute) and the cures, forming a weak powdery solid.

I have had some success reducing it when there are areas that I cannot reach mechanically by some combination of increasing the exposure time during printing, and by increase the duration and agitation of the IPA bath.

MakerJuice and FTD seem to be more prone to forming this type of residue, whereas 3DM-ABS rarely does.

Thanks James, what you said about partially cured resin mixing with water/alcohol fits. The white stuff appeared much more strongly while I was rinsing with IPA and then water. After that I put the part in the UV box.

Based on what you said, I’m thinking next time I’ll fill my sonic cleaner with IPA and put the part in there for a while; then rinse with water and UV post-cure.

Yeah, I’ve been experimenting with a pre-wash in my sonic cleaner in soap and water before going into IPA.

There was some discussion on one of the other SLA 3D printer forums about using IPA in the sonic cleaner, and there’s some concern that the combination of heat generated by the cleaning process and the close proximity to electronics might not be the greatest idea for alcohol, and I haven’t tried this myself.

Let us know how you decide to do the IPA bath and how the results come out!

Will do. Thanks for your thoughts.

As a followup… I can consistently avoid the white residue by not having a situation of uncured resin + IPA + soapy water at the same time (per James’ reply above). I’ve been rinsing the print thoroughly with IPA instead.

I use a super fine bristle art brush in a tub of IPA and carefully do as much as I deem reasonable to remove the resin with IPA. Then Cure in the sun in tap water and it’s reasonably successful. However, like most things, any intricate part is prone to support removal and sanding. I’ve learned to accept that it’s not likely to have white sand or Resin spots on the print completely gone unless you have a part that you can print flat on the BP and will require no supports or finish work such as sanding.