Materials list for 6" J-core pour?

I'm pouring a 6" J-core where the riser is to fit in a 55 gal. barrel.
How much fire-clay, perlite, and furnace cement should i get for the whole core?

Michael Valdez : I am going to be harsh here and tell you that if you do not understand how to calculate the area of a J-tube and the volume of its surrounding
materials, you are not ready to Cast your own core!

If you had come here and said My Feed Tube is going to be 16 inches deep so my Heat Riser needs to be 48'' and the length of my Burn Tunnel is 24 inches center
of opening to center of opening, we would know you understand the ratios inherent in a good Rocket Mass Heater RMH, The fact that you did not supply us with those
dimensions has to make us wonder if you are going to have enough mass to keep the Burn Tunnel from cracking, and that you are not going to try to make the three
sections from one continuous pour ( you could try and it will undoubtedly crack!)

If you had asked instead 'how do I find out how to figure the ratios to find total mass, and where do I find out the amounts of each material' Most of your Fellow
Members would probably spoon fed you the information because you asked the right questions! Most will still want to !

So that you understand both the how and the why of constructing a Rocket Mass Heater, RMH, and can calculate the ratios and the Constant cross sectional areas to
assure yourself you are not wasteing expensive materials, you should first Download a copy $18, of " Rocket Mass Heaters '' from rocketstoves.com and
learn the simple calculations with the use of 5th grade math !

The time effort and money you save by doing it right the first time will only be your own ! Success comes from effort Big AL !

Allen, thanks for your advise. i'm sure it's well intentioned.

Unfortunately for us town-runs are very far and very few between.
So ready or not, yesterday i had to buy the materials based on my own calculations.
My post was simply intended to get some feed back from others in order to check that my calculations were at least in the "ball-park".

allen lumley wrote:Michael Valdez : I am going to be harsh here and tell you that if you do not understand how to calculate the area of a J-tube and the volume of its surrounding
materials, you are not ready to Cast your own core!

..... my Heat Riser needs to be 48'' and the length of my Burn Tunnel is 24 inches center of opening to center of opening, ..........

Interesting. I have similar questions as Michael. Looking for directions for purchasing (or scrounging) materials. But I bought the 4 DVD Set from the Wood Burning Stoves 2.0 4 DVD set and Erica clearly says from end to end of the tunnel not center to center. I guess I too, will buy the $18 Rocket Mass Heaters '' download from rocketstoves.com and see if that clears anything up. I was reeeeally hoping for the Shippable Core, but see that it has not come to fruition as yet.

Hopefully, that download will give me enough information to forge ahead (pun intended) on my two RMH projects. One for my shop and one for my wife's greenhouse.

Perhaps I should start another thread, but .......

I am at that point in my life where not everything that goes in........... stays in my head. OK, OK, so it's always been that way, but more so now. So I watched all 4 DVDs, and feel I have the basics down and have the safety covered, and am trying this in my back yard first. But I don't remember things like, "Is 2000 degrees fire brick needed for the entire J tube?" "Where do I find the insulation wrap... and what is it called?" If the whole thing was put into text so it could be searched, I would probably not have to bother anyone with all these mundane questions.... that have been likely answered many times on these forums. Perhaps searching the forums will be more fruitful. Hmmm... let me see. Is that possible? You might have guessed, I'm new here. Not new on this planet, mind you, just new to this forum. There is waaaaaay too much information in the forums for me to read it all. I like the reference manual technique. Find the one chapter or paragraph that pertains to the problem at hand and go get the specific information.

I built a mock up in my back yard with regular red brick and just plain old clay mud and didn't seem to have any problems. Just a J-tube though, no barrel yet. The dimensions were: 5 1/2" x 5 1/2" tube, the same dimensions you mentioned... 16" x 24" x 48" But it didn't seem to get as hot as I thought it should, either.

I'll go get the download before you scold me.

Scott Saxon wrote:

I'll go get the download before you scold me.

OK, that did it. Appears to answer all questions.

Thanks,

Scott

Scott Saxon : I really like the Operator Friendliness, and instant gratification of Downloads ! I am glad that you are finding answers to your questions.

When in doubt, always go with what Ernie and Erica tell you, Ideally the Heat Riser should always be at least 2 Xs the length of the Burn tunnel, we have
a member who ran with the Shortest Burn Tunnel he could make, and then ran into Overheating problems at his Feed Tube, he created an elegant work
-around that also gives him some additional hot water, this is partially how discoveries and advancements are made.

I Know that I would have concealed against it ,and if asked I would have said, ''tear-it -out!'' ''Do-it-right!'' I do try not to get trapped in the '' But,
but, but- we've always done it this way '', I have an Alarm set to go off when I try to sneak in one of those kind of answers, and yes I forget shit too !

For the Good of the Crafts ! Big AL