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Tim Allen

Member Since 04 Dec 2014
Offline Last Active Today, 04:40 AM
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#124959 Old Kiln - Unknown Max Temp

Posted by Tim Allen on 06 April 2017 - 06:36 PM

OK, here's a quick calculation.... heat is lost from the kiln essentially as a function of the surface area of the chamber, at a rate that is determined by the insulation (e.g. thickness of the brick as well as what kind of brick).  Your kiln (assuming a rectangular volume 17.5"wide  x 17.5" deep x 13.5" high) has a surface area of 1557.5 square inches.  At 4800 watts heating power (20 amps at 240 volts), that works out to just over 3.08 watts per square inch. (if your kiln is round, 17.5 diameter by 13.5 high, then your surface area is 1222.6 square inches, which means you've got 3.93 watts of heating power per square inch).

 

Our Gare 2318 (round kiln 23" in diameter, 18 inches deep) has a surface area of 2130.5 square inches. It is rated at 7200 watts heating power (30 amps at 240 volts), so that works out to 3.38 watts per square inch. Our kiln is made of standard 2.5 inch brick. We understand ours is supposed to be able to achieve cone 6, but we only use it for bisque so don't know how high it can actually go (we got it 2nd or 3rd hand).

 

So if your brick is similar (2.5 inches), I would guess that the "should be capable of cone 6" advice is probably close....




#71840 Two Questions About Manganese Dioxide Use

Posted by Tim Allen on 14 December 2014 - 07:44 AM

Babs,  Yes, Manganese Dioxide is MnO2  but Casey was writing MgO2 which is non-sensical because Mg is the chemical symbol for the element Magnesium -- not Manganese -- and Magnesium (Mg) will only ever have a valence of +2 so it's oxide will always be simply MgO, Magnesium Oxide, no "di-" prefix needed.

 

ETA: this thread is, of course, about Manganese Dioxide (MnO2), not Magnesium Oxide (MgO), which is exactly what I was trying to clarify. For those who don't work with the Periodic Table and the Chemical Symbols for the elements on a regular basis, it can be easy to get confused, especially with elements that have similar-sounding or similarly-spelled names (like Manganese and Magnesium) and thus similar Chemical Symbols, as well as with elements whose Chemical Symbol has no relationship with the element's common name in English (like lead, gold, silver, antimony, tin, etc...).

 

Potters are called potters because they make pots, obviously. Anyone know why plumbers are called plumbers? <_<




#71730 Two Questions About Manganese Dioxide Use

Posted by Tim Allen on 12 December 2014 - 08:02 AM

A month-old thread, but just to note that the chemical symbol for Manganese is "Mn" not "Mg" -- "Mg" is Magnesium, and it's oxide would be MgO not MgO2

 

A crude test of the ventilation system could be accomplished with a smoke-producing smoldering splint of wood -- where does the smoke get drawn to? 

 

I would want to be sure of the balance between the room exhaust fan and the kiln vent fan; where is the make-up air coming from? in the extreme case, a very powerful room fan could be drawing air in through the kiln vent despite the best efforts of the kiln vent's blower...




#71401 To Sell Or Not To Sell? That Is The Question

Posted by Tim Allen on 07 December 2014 - 06:27 PM

Lee,

 

To follow up on John's advice, you don't even need to register a DBA with the state of NH if you are operating your business under your own name.

 

INAL, but not sure why you would want to form a LLC -- unless you are carrying a whole lot of debt to support your pottery, there really isn't a lot of liability exposure just making and selling pots on a small scale (assuming you are not using toxic glazes, etc..). We did ask our lawyer about it when we were meeting with him on another issue, and he agreed -- just stick to a sole proprietorship for starters.