Using castable resin for a larger object

I modeled and printed this bird with the standard black resin. It was a hollow copy. I had no problem. I wanted a bronze version of the bird but I realized that my escape hole was probably too small for a cast and made a solid version to cast in the castable resin. I had 2 failures where the longest dimension was about 4 inches. The nice people in support said it was probably because I had so many twists and turns in the project and some of the solid areas ended up parallel to the platform and that caused the difficulty. They also suggested that it might be too big a project for the castable resin.

I printed a third version which was smaller and I thought I got it until I began removing the supports and found that in an even different place the bird was cut into 2. The nice guy in support suggested I put up my images and tell this story here in the hopes that someone out there with more printing experience would know what my mistakes were. I think 3 print failures is a lot. I might have pushed this castable resin a little too far and I would like to hear from other people about this. I plan to do more projects like this and would really love to get this one right eventually though I’m thinking this castable resin might not be the way to go.

That’s beautiful…a shame it’s breaking.

Have you tried to re-orientate the model? My suggestion would be to try to orientate the model such that as much of the model as possible does not overlap with itself. Then run your support routine an then edit the supports so they don’t land on detail features of your model that would take away from the appearance. I don’t know how much experience you have with trying different model orientations but my experience shows that you can dramatically improve the print results from this method. Are you using the Preform automatic orientation and support routine?

Nice work on your model by the way! I hope you have success.

Mike A.
Scout Design & MFG

If mlabirds suggestions don’t work, then why not just print it in two separate pieces and fuse them together afterwards with a little resin and UV light?

For a little strength, add a little hole on one side and a little extrusion on the other side so they slot together.

With this method, you can even print one of your masterpieces bigger than the build volume.

I tried 3 different orientations including 2 that had worked with the standard resin. I got so annoyed I sent my preform file to support and said you orient it.That’s the one I used for the print that’s in 2 pieces. At least that one had everything there.

Marco’s remark got me thinking, not about doing it in 2 pieces but the fusing together with resin and uv. THAT’s interesting. Could I use a paint brush and fill in little dents that happen sometimes when you flick off the supports instead of cutting? Sanding etc doesn’t always solve that little annoyance.

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Yes; if you search you’ll find several people using 405nm (“UV”) lasers for exactly that.

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We have a small UV flashlight and a small laser for that purpose. sometimes we use sticky wax or some other casting wax to adhere pieces together.

Hah! then I could have corrected some other things I was unhappy with on that print. I was having issues with the fact that this was a subtractive process. but if I can add with wax or the resin that changes lots of things.

Erich, this is the print I sent to you.

I use medium viscosity superglue to fill small pock marks. If you use kicker before it flattens out, you have a nice bump to sand back where the pock used to be.

Myself, I would use the hollow version and fill it with something like Hydrocal. I do this for a number of items that I need to send to Shapeways. Because of costs hollow items are far cheaper. I then fill with Hydrocal before making a RTV Silicone mold for casting in resin or white metal.