Lee,
I was thinking about buying the bead cube having just sold my ceramic kiln, but then thought I may save up and go for the Maxi, I just wanted to ask why there is such a difference in top temperature between the 2 kilns, I may want to do some smaller fused pieces and also silver work and want to know if the Maxi can cope with this?
Cheers,
Mandyxx
Hi Mandy, it is quite simple, it is all to do with the element system used.
To heat the MAXI we have used a Stainless Steel mineral insulated element (MI), similar to the type you would see in a kettle.
The reason for this is that they are virtually 10000% safe electrically, as you can imagine when you think they are submersed in water in a kettle.
The complexities of fitting what we believe to be a safe door switch to this type of kiln left us with the MI element as the best option.
The downside to the MI element is that it has limited temperature capabilities, around 850c....BUT...long before 850c regularly and the MI element will loose the capability to carry its own weight and start to sag leaving the kiln looking rather unsightly and lessening the element life. So we set the top temperature to 650c which is above what is required to anneal yet low enough to ensure the element will run for literally years.
When we worked out that we needed to use the MI, we also come to the conclusion that the MAXI should be designed and marketed as an annealer only so we concentrated on making sure it did that job to the best of its capabilities.
The Bead Cube is heated by winding a standard coil element around the chamber muffle, ie the chamber is like a refractory bucket lying on it's side. The element heats up and forces the heat through the wall of the muffle and into the chamber.
This way doesn't need a door switch as the muffle protects the user from the bare element behind and the muffle is very strong.
The top temperature is limited to 950c due to the insulation used around the element.
Again, the Bead Cube is an annealer but it will fuse etc, Just remember there is a split across the front of the door that never fully closes to allow the mandrels to pass through so common sense says that will have some effect on the chamber temperatures once up to fusing temperatures.
On a final note, we did look at making a Bead Cube style muffle for the MAXI to allow it a higher temperature but it had manufacturing and cost issues due to its large size.
Hope that helps,
Lee
Wow, brilliant explanation, thanks Lee! I found out stuff I didn't even know I wanted to know ;D
Quote from: Lush! on June 05, 2009, 04:32:02 PM
Wow, brilliant explanation, thanks Lee! I found out stuff I didn't even know I wanted to know ;D
Exactly what I was thinking :D
While we're on the subject of the Maxi kiln, Lee, my kiln has a gap between the two skirts/fringes that are attached to the bottom of the doors. I can see clearly into the kiln through it and wondered if it should be like this. I can post a pic if you need to see it.
Thanks
Bev
x
Thanks Lee,
great explanation, all makes perfect sense now, think I will be saving for a maxi now,
Cheers mate,
Mandyx
Yes, there is often a gap between the brushes pal. Makes ho fidderence at and is nothing to worry about.
Feel free to send me a pic if you still have concerns
Quote from: Lee - Kilncare on June 08, 2009, 09:38:49 AM
Yes, there is often a gap between the brushes pal. Makes ho fidderence at and is nothing to worry about.
Feel free to send me a pic if you still have concerns
Ho fidderence - well we'll stop worrying then ;D
;D ;D :-[