Cut bricks as opposed to more mortar?

[Stray Catalyst]

Forgive me if I'm asking a question that's already been answered - I'm currently reading the Pompeii Oven Plans V2.0, but it's leaving me with a few questions.

I have unlimited access to a wetsaw, with a large enough blade to cut bricks. I'm familiar with fixturing to get precisely angled cuts with a high degree of repeatability. Would it make sense to cut firebricks to the angle I need, as opposed to building up the outer edges with mortar to achieve the same angle? I expect I'd still need the mortar, though it'd be a much thinner layer of it, and the rest of the oven (cooking surface, insulation, etc) would be the same.

Stray

[carloswlkr]

Stray,

Several people have done what you are suggesting. I had the benefit of a brick foundry that sells 22 different size bricks, so was able to buy the proper tapers to build my dome. I was extremely pleased with it. Didn't need to use any support for the dome at all, and the mortar was kept to a minimum and to fill in the vertical spaces between the bricks, not create the angle of the dome.

If you've got the patience and desire to do it, I'd say, go for it!

[Stray Catalyst]

I've heard from a few people on the subject, and I think it'll be easier for me to use bricks in the normal shape, and build up to angle with mortar. Can you give me the URL for that brick place, though? That's not an option I'd considered. I probably can't afford to get them (I'd have to expect they'd be more expensive than normal firebrick) but I'd love to see what they have.

Stray

[phippsj]

Is there any difference in strength? If I take the time to cut and taper each course of bricks, would the oven be less likely to crack? Or, will the extra mortar provide more thermal mass?

It seems that the cracks would occur between the mortar and a brick, in which case I am not sure all those cuts would make a difference. I would also like to hear people weigh in on this issue as I am getting ready to start my second course.

[carloswlkr]

Stray Catalyst,

It is certainly less work and easier not to make so may cuts. I only did mine with tapered bricks because they were available for the same price at the foundry here in Costa Rica (ladrilleralauruca dot com). If they were more expensive, I would have gone with the standard size fire-brick. The hardest part of building my oven was cutting all the bricks in half, and as the dome went up, cutting off the inside corners. I was using a mitre saw with a diamond blade, but each cut took me easily 3 or 4 minutes. I was working alone, at nights and on the weekends, and managed to get about one or two chains done per day! Not a speedy process. If I had to cut tapers as well, I might still be building!

phippsj,

I have no idea if there is any difference in strength once hardened. I was able to do the whole dome without any support structures, as each chain supported itself. But I'm not an engineer, so I don't know if it makes any difference.

[dmun]

Is there any difference in strength?

No.

If I take the time to cut and taper each course of bricks, would the oven be less likely to crack?

No. Cracking seems to be independent of brick shape. There can even be cracks in mid brick.

Or, will the extra mortar provide more thermal mass?

No. Mortar and firebrick have about the same thermal mass.

About the only reason to build a cut-every-brick dome is as an exercise in craftsmanship. If your only goal is cooking, then just trim the edges of the inner face of the bricks just enough to get the look you want. Even that's not necessary.

[Stray Catalyst]

I'm looking for sturdy, comparatively inexpensive, and fun to use. I'll stick to the tried-and-true methods, and forgo the exotic cuts wherever I can use full or half bricks.

Stray