Fire Brick Alternative

Is there a alternative to fire bricks? They are very costly and hard to find more then a pack of 5 here in south east mo.
I have a few books but none explain how to build the heat riser without fire bricks.

Hi Mike;  
You can build a 5-minute riser in... well about five minutes.
A 6" riser uses an 8" pipe with 1" of Morgan super wool on the inside.

A lot of folks have trouble locating heavy fire bricks. Most are not looking in the correct place.
I can tell you that out here in the sticks I pay just over $2.00 each brand new for full thickness F.B. as many as I want.
Box stores will not have them, and wood stove stores will not have them,  Both might sell a 5 pack for bunches of money but there are better places.
I don't know exactly where you live but being back east there are big and bigger cities not that far away.
You need to locate a masonry supply house. All big cities will have one.  They will sell concrete blocks,  decorative stone, and clay building bricks, And they will sell full fire bricks and split fire bricks and probably carry fire clay as well.

Check around you might find a road trip in your future...
Or you can order Morgan super wool from me.

Hi Mike;
here are a few threads about Morgan and risers.
https://permies.com/t/153507/Morgan-Superwool-ceramic-fiber-blanket
https://permies.com/t/95849/Working-Morgan-Superwool-ceramic-blanket

Approximately how many full and split FB are required for a typical 6" RMH?

Hi Khris;
I have never counted an exact number as I always want extra on hand,  but for a 6" J tube  I would have 25 full bricks.
If building a 6" batch box I would recommend 35 full bricks.
You should not need split bricks, they cost more and crack easily.

At the correct location, a firebrick should cost apx $2.25 a brick.   Do not waste your money on the 6 pack of bricks from tractor supply/box store.
Locate a masonry supply and source your firebrick and fire clay there.

You can use fewer firebricks if you build a 5-minute riser with Morgan super wool.

Locate plain clay bricks,  play in your yard, build a 6" J tube, fire it up see how well they work.
Count how many bricks you end up needing and you will have an exact number and experience at putting one together.

I have over 70 firebrick left over from 2 bread ovens i had built years ago they were 5' x 7' .. the business died, ( location) l'm thinking about putting a RMH im my honeys' new shop, 24' x 24' open space. Learning lots here, much appreciated. How long does it take to create one of these masterpieces?  6"

Acme brick in Springfield had them, although not cheap.

Hi Khris;
If you are only wanting a 6" J tube rocket and not a mass heater then a few hours or so and you can build one,
If you're wanting a Rocket mass heater then it could take you maybe a week.
It depends on what style of mass and what materials you have available to use, how much help you have.

What style did you have in mind?
A J tube?
A batch box?
A piped mass with solid fill?
A stratification (bell) chamber?

J tube with solid mass fill type