|
|
Post by steve999 on May 8, 2017 17:42:07 GMT
Evening all.
I've decided on using refractory castable cement for the 'shell' of my dome. How thick should the dome walls and ceiling be? I'm guessing around 50mm, however I could be way off. Also, the cement comes in 25kg bags. For an average size dome, how many bags do you think I'd need? Apologies for my ignorance, this is my 1st build. Thank you all in advance.
Regards,
Steve.
|
|
|
|
Post by downunderdave on May 8, 2017 21:13:26 GMT
Evening all. I've decided on using refractory castable cement for the 'shell' of my dome. How thick should the dome walls and ceiling be? I'm guessing around 50mm, however I could be way off. Also, the cement comes in 25kg bags. For an average size dome, how many bags do you think I'd need? Apologies for my ignorance, this is my 1st build. Thank you all in advance. Regards, Steve. Commercially cast WFOs are usually around 2" thick. This gives a pretty good balance between heat up time and sufficient thermal mass for retained heat cooking. Use the formula 4/3 pi x r x r x r = volume of a sphere to calculate required material. Work out volume of the sphere using the radius for outside minus the volume of the inside sphere using inside radius and halve the result because it's a hemisphere. The material not needed for the door is roughly the amount required for the entry if you cast that thinner. Add around 15% because once mixed with water there is less volume of wet material compared to the dry volume. My 25 kg bags of castable always weigh 24 Kgs and have 18 L of volume. That works out to around 15 litres of wet castable per bag. |
|
|
|
Post by steve999 on May 8, 2017 21:22:36 GMT
Hi Downunderdave.
Thank you so much for the advise for working out material. I think I need to be a NASA scientist to work it out properly. :-)
|
|
|
|
Post by downunderdave on May 8, 2017 21:28:29 GMT
Hi Downunderdave. Thank you so much for the advise for working out material. I think I need to be a NASA scientist to work it out properly. :-) No you don't this is primary school maths, ask one of your kids.  |
|
|
|
Post by steve999 on May 9, 2017 10:33:00 GMT
Ha, that would be embarrassing if my 8yr old worked it out for me :-)
|
|
