Tilting Kettle Furnace Under Construction

[Barren Realms 007]

That first link dosen't seem to work.

You didn't do any calculations on this before you built the furnace?

 

[lazersteve]

I had no idea of what normal exterior temperatures should be in order to do any calculations and I didn't find the formulas until today. I based the thickness of my wall on the fact that insulating firebricks are 1.5" to 2" thick and they tend to remain relatively cold when melting gold in them. I found today that G-26 firebrick has a k of 2.6 at 2000 F or about half of the refractory I'm using.

I can't seem to find anyone who can post the external temperature of their furnace verses the operating temperature along with their refractory specs. The above links mention a 600F (315C) external temperature in one of the examples.

I managed to locate the k value of the refractory I using as 4.4 at 2000F ( 1093 C). If push comes to shove I can bore out this furnace 1/2" and add a layer of 1/2" alumina mat (k = 1.65 at ~2100F) to bring the radiated heat under control.

I'm hoping someone will post readings from their furnace before I go through the trouble of making mine run 'cool to the touch' on the outside.

Steve

 

[Noxx]

It seems some people need formulas

I did this nice excel sheet for me. Unfortunately, it's in french but might still be able to understand.

There are interesting html links too!

 

[Barren Realms 007]

I haven't seen any people post what the temperature is on the outside that was taken with any kind of instrument. I'm going to say 99% of the people that build these just throw them together with out any foresight. You might get lucky and have someone send you some data on one.

The fire brick possibly transfers less heat because of the air pockets.

I had to put a piece of sheetrock under my crucible because I cracked 2. The brick it was setting on was transferring too much heat from the crucible and cracked it was my tought. As soon as I finish with the 2 that are cracked I will check to see if I am right about this with a new one.

 

[HAuCl4]

Sorry can't find my old heat transfer books for the formulas.

 

[oldgeek]

I was wondering how this project is coming along? Can you give us an update when you get a chance?

I was going to just "throw something together", until i saw your project. It looks so versatile I am considering going the extra miles to use your design. (as long as you don't mind!)

Thanks
Scotty