Clear Cast Success?

Support & Troubleshooting Materials
1

Has anyone had success with the Clear Cast resin and shell castings?

I’m going on my 3rd tank of Clear Cast resin and have had quite poor results with blow outs and porosity casting in bronze. Now, I understand that this is a trial-and-error thing, but the kicker is, I had gone down a nearly 2-year process of experimenting with clear v4 and ended with some truly incredible results with no issues at all. I had only learned of the new Clear cast resin when I was going to purchase more normal clear.

For my previously successful castings I had used the free Meshmixer to hollow and lattice. My results were all successful with wall weights of .5 to .6mm, lattice diameters of .5 to .6, and spacing of 4 to 5 mm. One parameter that I took into consideration is percentage of volume between pre and post hollowed and latticed designs. Anywhere under 30% I had great results.

I was naturally excited to see the new resin release and figured if I had such great results with clear v4, it would be no issue switching. Went with .5 wall weight, .5 diameter and 3mm spacing. So really the only change was the spacing, however my percentages were all under 30% so figured it wouldn’t be an issue.

With the poor quality of these last castings, I’m a bit stumped. The designs were nearly identical, panels with different logos and designs in them. It was one large batch, and I’m not completely ruling out issues with the metal pour as its possible and they put the gates on a bit different than in the past. It was still surprising after so many successful castings previously with Clear V4.

Some things I’ve noted and are questioning

With the clear 4, after curing it was super crispy and yellow. I really tried to extra cure them based on a comment I had seen on here a while back. I did have some issues with warping at the recommended 60c temperature though, so when I read in the white paper for Clear Cast that the suggested temp was 35C with the option of a post curing schedule with no heat too, I decided to go this route to avoid warping. I tried a few different things, but ultimately, they all got at least an hour of time in the cure. Not sure if this could be causing issues.

Most of my previous castings I used wax to plug the drain holes but switched to resin to create a cleaner look. Another possible issue with expansion and casting?

I’ve compared the TDS and between clear cast and clear V4 and they are Identical with exception for the V4 not having thermal expansion or ash content information, to which I would love to know just for curiosity’s sake.

I’m printing a few more pieces with my leftover V4 as well as more in Clear Cast in hopes that they all turn out and this run was a fluke, but figured I’d post just to see if anyone had any info to add to the conversation!

2

I’ve seen/done a couple of castings with Clear Cast successfully, and didn’t see it fully blowing out in the metal, generally when something fails with Clear Cast it the resin expands so much that it breaks the shell, so I’d definitely be curious to hear how your next round of tests go. It should generally perform the same as Clear V4 in every way except that it will generate less ash during burnout, and expands marginally less.

As far as the post curing, you can still try the 60 °C cure, it should be fine for Clear Cast, the reason we recommend lower temperatures is exactly what you saw - it ends up warping, so we avoid that by going with a lower temperature. It only needs about 15 minutes to really cure, but that is after it has fully dried of any IPA, which typically I saw that 30+ minutes in the cure (preheating to only 35°C) helped. If remaining IPA is the problem, you can definitely let the patterns dry for longer or air blast them for more time.

2 Likes
3

Thank you Sean! I’ve had plenty of full blow outs in my original testing with V4, these recent ones were more surface and small cracks/fissure issues. I had a feeling the two materials were very similar, thank you for confirming. Since V4 has been phased out with V4.1, are there any noticeable differences in that regard between the two? Also, I was wandering since they are so similar and the same price, can I use the Clear Cast for the few random non-casting projects I have, such as a larger solid piece and expect the material to react the same as your current Clear Resin.

I’m generally confident now that it was an issue with gate placement and the effect on the pour. Ive been attempting to add the gate features and I think its been throwing the team off as they think they are features of the design. I have been working with the same foundry for 8 or so years and they have been great so ill chat a bit more next time I head there.

For the curing, I was mostly wondering if an incomplete cure would by any chance create higher expansion. The IPA shouldn’t be any issue, I generally leave for a day or more to dry before curing, and then they sit for several days before plugging the holes and then even longer before I finally get to taking them to my foundry.

Much appreciated!

1 Like
4

You may see some difference between the two on thicker parts, I don’t believe we ever tested it at thick cross sections. You can certainly try printing parts with Clear Cast to see if they are close enough, but I’d definitely be a little bit cautious when you do just to be sure that there is nothing dramatic causing issues.

Incomplete cure causes more issues because uncured material/unwashed material can make problems for the casting, mainly by interacting a bit with some investment systems. I’ve also noticed that it makes the shell a bit softer. I don’t think there is a dramatic change in expansion, though I’m not sure it was ever explicitly tested.

Good luck on the next trial, I hope it works out for you!

2 Likes
5

Okay, this makes total sense. Really no issue having both resins, was just wondering.

As for the Incomplete cure, I’m now thinking we have found my issue and leads me to a few more questions I’m hoping you could answer. The castings I have been doing have some finer detail impressions, roughly 1-2mm deep and a 2-3 mm wide. These are the areas that seem to have issues, which would align with incomplete wash and or cure in the impressions in the design. The way I have my prints supported, I have noticed a few times some still sticky resin in these areas that I try to clean with a q tip, as with the thin walls can get a bit soft if they are in the wash too long so I’ve avoided going back in.

This last batch was the first that I cured at a lower temp to avoid warping and ran in the cure longer. Ill assume that even though I left them in the cure for a full hr at 30*, it was not enough. My main question would be, is there a sliding scale of time in the cure vs temp that would achieve the full cure. IE 24hr cure-room temp etc. Secondly, if there is still some resin that has not been washed off in spots that has gone un-noticed, in theory a really thorough cure would take care of these areas, or would they still be potential problem spots because it was leftover resin as opposed to printed in the machine? I’m going to assume the lack of deep and thorough cure is my overall issue and sounds like I have my solution going forward.

Thank you so much for the insight and time!

1 Like