New build - 1.2M dome

[jonv]

This picture helps a lot, thanks. I was still wondering if each brick needed to be different! I've seen quite a few that looked as though they were all cut the same, but then perhaps they did not intend them to blend with the dome.

[UtahBeehiver]

If you look at the pic and the inside of the dome area, you can see how one side vs the other side changes as you move down the arch. It does make a smooth transition to the arch and dome interface. But that is up to you. This is a area where it won;t be seen one the oven is done. If you a concerned about cutting each brick then don't do it at all and just tie in the dome to the arch but this is worth the effort.

[jonv]

Thanks; will definitely give it a go. I'm planning to cut each brick to fit anyway, it's just a case of working out the right angles...

[JRPizza]

What I did is keep the top and bottom surfaces of my arch bricks parallel, meaning the top and bottom were both "tangent" to my arch form, and I cut all the bricks to sort of match the angle of the top dead center brick (you can sort of see this in the "selfie" I took). The starting point of the angled portion changes as you go around the dome, to account for how much more the arch sticks out at the top vs bottom (see the side view). Since I built the arch as I added courses, I just did custom cuts on the bricks adjacent to the arch to match the angles on the arch bricks. I attached a few pictures to show how I attempted to do this - I got smarter as I went as some of the first cuts were crude. I also had to deal with the dreaded droop, as I didn't pay enough attention to keeping the bricks adjacent to the arch tipped up like the rest of the bricks in the row, an error that adds up and if not corrected results in droop.

[jonv]

Thanks for that. I shall be on the lookout for the droop... I have a bit of work to do before I have to decide how to cut the arch bricks. I cut the half soldiers today and hope to get them mortared soon The tops are angled to match the arch bricks for the first proper course.

[Gulf]

Here is a quick and easy method to prevent the dreaded droop. Oasiscdm (Colin) prevented this by attaching a guage to the IT, using the floor as a reference.

[crisp]

Nice tight joints . I did my arch transition like these pictures, but my dome is neopolitian ( a lower dome height ) with two radius's, not a half circle, likewise the arch entrance is not semi circular. I cut the top of the arch at the angle and level with top of the the third course. It's just another way of doing the transition. The first five courses were a steeper radius, then a flatter radius.

[jonv]

Gulf - that's a great idea, and one I had not picked up on before, so thanks a lot for that - I shall make use of it I did see someone use a laser line to help keep everything level, so I shall probably deploy my laser for that purpose too, but I rather like the idea of something solid on the IT.

Crisp - it's a different design to what I had in mind, but that is a really attractive entry. It's a pity that the inside is not readily visible - I would want to show that off! I was planning a rather dull semi-circular arch on top of a short vertical length...

[JRPizza]

I had intended to make a thread on droop, but never got around to it. I think understanding why it happens is important in preventing it (which I didn't), so here is what I think happens. As you build up the dome the bricks start to angle up as shown in the first picture as they ride on the bricks below. This angling does not happen adjacent to the arch as there are no bricks on the arch side to provide the rise. This is shown in the second picture (my oven ). If you give each brick adjacent to the arch a slight angle up with some extra mortar or a brick chip (to match the rest of the bricks in the row, I think you can eliminate the droop.
PS, I "borrowed" the first picture from someone on the forum - can't remember who but "thanks"

[jonv]

Interesting. I will pay particularly attention to those bricks and pack them up as you suggest to keep them on track. Will be interesting to see if I can avoid it or if it still sneaks up on me even with the benefit of your past experiences!

[thevance53@gmail.com]

Maybe I was a little too worried about keeping each chain as level as I could, but if you keep adjacent bricks level, you can't end up with the droop. The first brick is the key to the chan and I had to start over a few times after trying to start a course with a brick not level or on the wrong angle.

[jonv]

Not a lot of progress to show for the last couple of weeks but I have at least managed to mortar the soldier course. I was a bit surprised just how tricky it was, so I'm hoping the next course will be a bit easier now I have a reasonable foundation to work from.

[UtahBeehiver]

Great looking start. Nice uniform and level brick work. What are you going to do about the inner arch? IMHO, it is easier to tie into the arch from the dome than to build the arch after the dome courses are in. I do suggest using and tapered inner arch, it will make the dome to arch transition much smoother.

[jonv]

Thanks

I'll definitely try to taper the arch. I still haven't decided whether to build the arch as I go or put it up first...

[UtahBeehiver]

Either would work but keep the arch ahead of the dome course vs dome course ahead of the arch brick.