36" in Seattle Brick Oven Photos Discuss 36" in Seattle in the Good Background Information forums; I'm using #50. I think it's fine, except in extremely tight joints (1/16") where I can't get a smooth enough ...

[kebwi]

I'm using #50. I think it's fine, except in extremely tight joints (1/16") where I can't get a smooth enough cream at the required thickness (thinness) without it breaking apart. For 1/8" and up, I'm sure my #50 sand based mortar is fine, albeit a little gritty to work with. In fact on the assumption that sand serves the same basic purpose as larger gravel in concrete, the logic seems to be that you want a larger aggregate for a larger overall volume of mortar or concrete. Thus, the larger sand is probably beneficial in some vague way for big fat mortar pockets, like on the outside of the dome up the curved courses, where the mortar spacings between bricks might be half an inch or more. That's my thinking anyway, I really don't know.

As for the effect of increasing the fireclay, as I did, I really don't know what effect that has. I have asked on FB several times and have never gotten really direct answer to the question "what does increasing the fireclay do to mortar"? I suspect no one knows what effect such a change has on the mortar. So long as the mortar still "works", maybe it just really doesn't make any difference.

Cheers!

[kebwi]

Cleaned the mortar from the previous outer-arch construction (no pics, see earlier post), then built a few more pieces of the outer arch and cleaned them up (shown this post).

Cheers!

[kebwi]

I completed (minus arch-merges) the first curved course today! I filled the gaps between adjacent bricks with brick wedges that were scrap from earlier cuts. I intend to continue this practice in an effort to minimize large mortar gaps, but probably only to the extent that I have sufficient scraps. If at some point I run out of scraps of appropriate size or shape, I probably won't intentionally cut up bricks for this purpose. I have a lot of scraps though.

Cheers!

[ThisOldGarageNJ]

Hi Keb...

From the pics it looks like everyting is coming along fine.....

Cheers
Mark

[kebwi]

Yes, thank you. The curved course went up with relative easy, thanks in no small part to the "dispensable" tool. What a fantastic idea.

[fxpose]

Wow, that's coming along beautifully! And I love the look of that arch.
I plan on using a center offset brick guide as well.

[kebwi]

Cut and mortared arch merges for the first curved course, thus completing that course. Phew!

Completely constructed the outer arch. This was the first (of three total) arches in which the last brick went in without a shave. I don't say keystone b/c in the case of one of the three arches, the center line was a mortar gap, thus that arch had no keystone. Just saying...

Notice that I was able to build the outer arch with only a few major mortars due to having built most of it in sections already. For example, the first photo represents a single mortar job on-site, since those four bricks came as a block from the basement. Likewise for the four just-off-center bricks on either side of the keystone. Earlier posts (and photos) make it clear what I'm getting at.

BTW, the dark-light-dark-light-dark pattern on the outer arch isn't a mistake. Once I realized that the cut bricks were exhibiting so a wide range of color I figured I might as well take advantage of it.

I'm a tad disappointed that the mortar gaps on the outer arch are not consistent. They are the by-product of attempting to conform to the protractor during construction. Sometimes the previous brick was a little low and required a fat mortar gap to get the next brick back to the right position...but at least the keystone is tight, which is not just aesthetic, but also structurally important, since the keystone will bear most of the weight of the flue.

The last photo shows that I cut a two-thirds length corner off the highest full-depth brick. That was a last minute decision as I was investigating my design last night. I'm hoping it will somewhat alleviate the shear stress between the vent side-wall and that last brick, which being rather steep will not be a very good load-bearing joint. By cutting the vent side-wall to notch over that last brick I should be able to improve the situation a bit.

Cheers!

[jmhepworth]

This looks really good. Nice work.

[Dino_Pizza]

I really like the variation in brick color. Good job picking that up and using it. Your mortar joints look even and just fine to me. I'm really diggin' the fully arched entry and the angle you cut off those entry arch bricks.
Nice job, Dino

[kebwi]

There's something odd about these bricks. The darker ones are noticeably harder to saw through, and I believe (although I haven't measured this precisely) that they feel heavier. I would almost say I got a mix of fire bricks of varying grade, whether low/medium or medium/high I really don't know. The other thing is that the bricks aren't a clear mix of two or three types, but rather contain a smooth gradation of color and hardness. The place I purchased them from refers to them simply as medium-grade across the board.

I don't quite know what to make of it.