40” Pompeii in Rhode Island

[mongota]

I'm glad my arch brick description helped, and congrats on customizing your IT to make it work for you.

I can't comment on squirrel tail, others are better suited. I recall DavidS having some concise input when others have asked in the past. If incorrect, my apologies for drawing you in David!

[NewEnglandNewb]

I managed to clear the inner arch. I did end up with a small case of “the dreaded droop.” In my case it was about 1/4”. I did also get out of round in way of the arch by about 3/8”. I compensated for the droop with the next course and got back to mostly round in two courses. I only have two courses left and then the plug. Hoping to have the dome done by the end of this coming weekend.

I start needing to fight gravity by using sticks to prop up the bricks while the mortar set at course 9. I have also been following Russel’s advice of morning the first brick of the next course as soon as I finish the previous one.

As for the squirrel tail vs. not, I’m leaning towards not. I think having a vertical chimney will be a good amount easier to build and more likely to perform properly.