Post by coastalrocketeer on Dec 16, 2018 18:05:43 GMT -8
I think it did ok for being subjected to 100k Btu’s and such extreme temp differentials from one area to another... while damp to boot.
The only place on the upper body of the thing that cracked all the way through was the top of the riser where it was super thin on one side. Had some pinholes on the side in that last 4 to 6” at the top. If it had been as thick as the rest I don’t think it would have cracked.
The base that flexed to pull away at the bottom on the feed tube half, and cracked, was a slightly different mix. It had 10g of MKP added to the EPK, and I don’t think I simmered the EPK with vinegar and phosphoric acid for as long. The brown of the air dry surfaces of that one did not occur so strongly on the later mix portions.
It seemed like the air exposed side that had the “brown skin” shrank more than the upward side the formed casting of the second mix was bonded to. I think it might have bonded better to the other side with the skin... or if I had “pre wetted” it better with some of the solution of binder zeolite and EPK, other aggregate powders mix and let that dry before trying to attach to that highly porous face.
The only place on the upper body of the thing that cracked all the way through was the top of the riser where it was super thin on one side. Had some pinholes on the side in that last 4 to 6” at the top. If it had been as thick as the rest I don’t think it would have cracked.
The base that flexed to pull away at the bottom on the feed tube half, and cracked, was a slightly different mix. It had 10g of MKP added to the EPK, and I don’t think I simmered the EPK with vinegar and phosphoric acid for as long. The brown of the air dry surfaces of that one did not occur so strongly on the later mix portions.
It seemed like the air exposed side that had the “brown skin” shrank more than the upward side the formed casting of the second mix was bonded to. I think it might have bonded better to the other side with the skin... or if I had “pre wetted” it better with some of the solution of binder zeolite and EPK, other aggregate powders mix and let that dry before trying to attach to that highly porous face.
