Hi,
So I just finished a new cast and let’s just say, it was terrible. The only variables I changed were the flask and metal temperature. I reduced the flask temperature from 580c to 450c and reduced the metal temperature from 960c to 950c. I did also flip the flask half an hour before casting to allow any trapped gasses to escape.
I am starting to think that the issues I’m facing are linked to the burnout of the resin and the fact it could possibly be leaving ash behind. My main assumption right now is that the temperature readout on my kiln could be inaccurate as @RandyD94922 suggested. The other minor assumption I have is curing the prints in bioethanol instead of standard ethanol is causing issues, although saying that, when I used to cast using Sirayatech Cast following their exact curing procedure, I was still experiencing similar issues on the castings.
From carrying out these recent castings, I have managed to disregard quite a few potential issues like the quality of the metal and investment, and also the cleanliness of the crucible. I also ensured that this recent casting was fully cured by washing in bioethanol for 20 minutes and UV curing for 15 minutes, but like I said, maybe bioethanol is a no go. I am also certain that the pitting is only occurring in 3D printed casts and not on wax casts which is another telltale that the pitting might be linked to the burnout of the resin.
A few observations I made about my recent cast is firstly, the areas which had the sprues entering the ring from the inside all had clear surface texture issues (as seen highlighted by the red circle). Does anyone possibly know why this rough surface texture would be occurring at all four areas the metal enters the cast? I also noticed that the worst of the pitting occurs along the top edge of the ring. I do find this odd as if the issue was linked to ash being left behind, how would ash settle on the ‘roof’ of the casting and not on the opposite edge at the bottom.
I didn’t spend much time cleaning up this particular ring as I didn’t see the point, but if anyone is able to determine anything from the information and images I’ve provided it would be greatly helpful. I think my next steps are to buy either a pyrometer or pyrometric cones to test the accuracy of the kiln, but if the kiln turns out to be accurate, then I am a bit lost on what to do next.
Thank you for everyone’s help. Hopefully I will get to the bottom of this eventually, fingers crossed.
Thanks,
Aaron
