franco b wrote:It's hard to give advice because I don't know how that piece is held in which might limit what you replace it with.
The firebrick that lay along the "V" shape of the firebox go up against the rear liner. If you look at the rear of the firebox in the above picture you can see how it sat vertically along that back wall just above the grate. It doesn't seem to have any purpose other than keeping the hot coal away from contact with the back wall of the firebox AND to provide secondary air from the primary air source. (I already have an independent secondary air inlet in the back of the furnace. Its where a combustion air blower is designed to go for wood burning I assume.) The rear liner doesn't really hold anything in place...
franco b wrote:Castable refractory is expensive, especially shipping and you have to construct some sort of mold to form it in. An alternative is a $10 pot of furnace cement from a plumbing supply which you can flesh out or extend with broken fire brick rubble and maybe some sand added.
How expensive say 20-30 pounds worth. I was planning a mold made out of some scrap plywood. I'd rather not attempt bothching something together
.. Although I did consider cutting some square brick to fit back there but was afraid I had no way to hold it in place since it will stand vertically.
franco b wrote:It's a tribute to your skill and patience that you have taken a badly designed stove and gotten practical results from it. Very few would have had the acumen to do that. I think we both know the real answer is to run the stove until it has given you adequate payback and then to replace it with a better design. Run the stove but keep a sharp eye on the used market for a bargain, especially now in the summer season.
Thank you for the kind words partner
.. I agree, been looking at other furnaces but I must admit, I'm not quite sick enough of this one yet
.. I enjoy the challenges I guess.. And shes done good keeping us warm