Finishing 3D printed models.

NHVRYGrayOGR Forum Member SUPPORTING MEMBER

I have only attempted two 3D models before. A GMC crackerbox truck tractor and a B train set of flatbed trailers both from Shapeways.

I have modified and finished many conventional models in ABS, Styrene, and whatever the injection plastic is, using basically automotive finishing practices.

The Shapeways model plastic was rock hard and none of my usual finishing methods of wet sanding would touch it. After I tried, the tractor took days in a warming oven to become "unwet". I ended up just using multiple coats of paint to hide the roughness. I was able to use a fine belt on a belt sander on the trailer deck, but that was a totally flat surface.

So, how does everyone finish these prints? I'm know there are multiple plastics used and I'm sure multiple differing opinions.

What is your method?

Gray Lackey

2/11/2210:32 AM

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Trainguy KenOGR Forum Member SUPPORTING MEMBER

Shapeway's Versatile Plastic is nylon based, which is probably why it's so tough and wear-resistant. I have used it a few times, but mostly in industrial applications where it just gets a quick coat of paint slapped on. I've also used their Fine Detail Plastic which I believe is a UV-cured resin. It's really sharp stuff, holds fine detail very well, but is very brittle and tends to shatter if you try to drill it or work with it. This was very frustrating when I was trying to do pewter homecasting a few years ago and my mold masters would crack the moment I touched it!

2/11/224:29 PM

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NHVRYGrayOGR Forum Member SUPPORTING MEMBER

I'm going to resurrect this thread and see if there are any more experiences since I last asked.

I'm working on a White Pass GE 90 class. Printed by Shapeways. The design is really nice, but as per above I can't get a good finish. I've learned previously I can't use automotive methods due to the material, natural versatile plastic, which was the only option offered to print it in. This will need handrails added so mounting holes will have to be drilled. Per Ken's comments above I have found resin prints (from a different company) tend to break when drilled into.

So far I have sanded twice with 100 and 180 grit paper. Once as it came, second after a coat of high fill primer. Every time I paint the "grain" seems to raise (wood workers term). See pictures after a second coat of sandable primer. I can and will sand again, but how do you keep the "grain" from raising on the final color? Would a clear coat of Testor's dull or gloss help? Just think out loud.