View Full Version : round or flat bottom crucible

Dennis Brent
04-11-2012, 07:20 PM
This ismy first time
trying to use this program, so forgive me if I make any mistakes. I just finished most of the construction on a new glassblowing furnace, which is a 16 inch diameter 18 inch deep cylinder it is an electric unit. And I'm not sure, if the best selection would be a round bottom or flatbottom crucible. In either case, it will be mounted on a short pedestal to raise it off the bottom.

Pete VanderLaan
04-12-2012, 02:38 AM
That is a really deep configuration for a pot Dennis. It would be OK if that is simply the chamber size but electric furnaces extract a cost from you for making the chamber unnecessarily larger. It is harder to get bubbles out of deep pots. I would go with a round bottom interior since that will also be a difficult pot to clean well.

Scott Novota
04-12-2012, 09:38 AM
Don't fret if no one else answers this post Dennis. You got the guy that knows the most about pots out of the gate.

Dennis Brent
04-12-2012, 10:09 AM
thanks for getting back to me so quickly. I really do appreciate the help.as usual I haven't explained myself well. I had narrowed my choice down to two pots a flat bottomed version 11 inches in diameter and 8 inches high, or a round bottom version 11 1/2 inches in diameter and 9 inches high.I was going to use the pedestal to raise the crucible to working height. I had allowed the extra depth in case I decided to go to a larger and deeper crucible Later on.I am wiring the furnace so that I can run with or without the lower elements and plan on filling the extra space at the bottom with insulation to decrease the volume. I had purchased the elements from Euclid's and they did some calculations.and I will have enough power to run without the lower elements. thanks again for taking the time to help me

Pete VanderLaan
04-12-2012, 12:44 PM
Use the second pot with the round bottom. It holds more. Your expense is going to come from two different directions: Your money gets spent on melting. Higher temps cost more period so the less time you spend on melting the better. Secondly, it's really frustrating to just get your glass fined out to then run right through it and have to melt again. The cost there is lost time. Mary Beth has both of those pots and will take good care of you if you are getting your pots from her.

I can't say about your element calculations. I like to run with 2200 watts per cubic foot but I'm not a subtle person, Just calc volts times amps equals watts and you're there. The big danger on wire equipment is losing an element and having to shut down without getting your pot emptied.