Fireclay for oven mortar - substitutes?

[agrasyuk]

Made a trip to the nearest brickyard .
While it has reasonably priced firebrick and supplies such as flue liners they do not carry fireclay (or at least that what they say). Instead they offered the expensive refractory mortar . Worst comes to worst I will buy that refractory mortar. with that I was wondering if fireclay an be substituted with :
1. red art clay . 22$ per 50lbs
2. Clay that I dug out during foundation work. I have a good pileup of it and I noticed that dry pieces can be ground into fine grey powder . Was thinking to sift the small stones out and count the remainder towards 0.25-.5 part sand as well
Opinions?
(I know I can crush some F bricks and will probably add that too. )

if I to buy the premixed refractory mortar, how much of it will I need for 36" oven if I'm not tapering each brick with the saw?

Thanks!

[agrasyuk]

For those in northern or Western suburbia of Chicago:
Located Fireclay supplier at Elgin IL - Great lakes clay.
wasn't to long of a drive for me, now I'm all set with materials.

[dakzaag]

That is great to hear, glad you are moving forward. Pics and more pics are always appreciated. In your plan to use square brick, I might suggest that at a a minimum you make cuts that are pie shaped. Unless you simple plan to break the firebrick in half with a chisel, you are cutting the brick anyway so making a slight angle cut is really no big deal.
If you are simply using halves, then the struggle will come on the upper chains where smaller pieces are needed. While I think that the compound angle cuts are not necessary for a typical back yard oven, I do think you need to plan on cutting a few brick.

[agrasyuk]

That is great to hear, glad you are moving forward. Pics and more pics are always appreciated. In your plan to use square brick, I might suggest that at a a minimum you make cuts that are pie shaped. Unless you simple plan to break the firebrick in half with a chisel, you are cutting the brick anyway so making a slight angle cut is really no big deal.
If you are simply using halves, then the struggle will come on the upper chains where smaller pieces are needed. While I think that the compound angle cuts are not necessary for a typical back yard oven, I do think you need to plan on cutting a few brick.

Thanks!
perhaps i should start a thread of my buid with pictures (now that I'm actually got to the WFO itself).
Thank you for the cutting note. I was indeed worried about split brick in the higher chains.
I will be using my old radial arm saw fitted with 8" segmented diamond blade. It's not a proper brick saw, but should survive and it can make angled cuts.