Back again … with a big mess. I think I have seriously learnt yesterday, that failure seems to be unavoidable if I want to learn! I poured bronze into the prepared and burned-out mold and everything seemed fine. But when I tried to uncover my hidden bronze beauty 😉 I couldn’t find anything. What an interesting experience … What happened? The mold broke in the bottom and all the bronze simply “fell” through and collected in the bottom of the flask. I didn’t even realize it until I scraped off the investment, never thoroughly checking the bottom. One of the mouth pieces was completely empty, the other a little recognizable but no detailed texture (like ramps, etc.) at all.
What do I think I have learned:
1. I let the investment dry for 2 days before I realized that a little moisture is good when you start the burnout, as I learned online. Next time I will let it site for 2 hours as the manufacturer suggests and burnout right after.
2. Too little investment below (above) the model to be casted. I will put more thought into the sprue size! Shorter channels and further away from the bottom (in casting direction).
3. The details in the one sound area were not detailed at all. I guess that had two reasons: 1. The melting temperature was not high enough and the bronze was not thin enough when poured. Next time I will make sure the bronze is at 1100 degrees celcius (2100 degrees fahrenheit)) 2. The temperature of the flask/investment/mold was too low while pouring and the metal cooled off too quickly when flowing. Next time it should be at around 650 degrees celcius (1200 degree fahrenheit)
4. Because I am currently not casting under vacuum, I need to pay more attention to the metal flow. I had some delicate areas in the mold that need the metal to flow up to fill them. This will be hard and depend on a lot of factors that are hard to control. Next time I will “visualize” the metal flow better and make sure there is only downflow necessary.
A little frustrating … but I will turn this feeling into motivation to get better! So stay tuned.
