42" Pompeii in Eastern NC

[Caliea]

Just answered one of my questions: the wet tile saw is too small (not enough clearance on the moving bed to the engine housing) to cut through a brick. Takes 4 cuts to score it enough to snap a brick in half. Not ideal for precision bevelling.

So... can I cut them dry?

[SableSprings]

Hi Caliea! I'm one of the folks that just used no angle/no bevel on my build--just cut 'em in half (until I got to the last two rows where I did have to cut a few angles). As JR noted, that method takes the most mortar...but the mortar is almost all on the outside and is hidden by your insulation & primary enclosure. I have read on the forum where builders have used the dry saw method. It works, but produces HUGE amounts of dust...definitely requires a good quality dust mask. Most folks either borrow or buy a 10 or 12 inch wet saw to do the cuts. I'm pretty sure there was one build where all the bricks were simply cut in half with a brick chisel (no angles, no bevels, and a learning curve I'm sure ). Since you've got another builder nearby, you might see if you can pick-up a wet saw from Harbor Freight and split the cost & use. Also, if you have any builder friends or contacts it would be worth checking with them. I borrowed a 12" wet saw from a retired contractor down the road with the promise of delivered fresh bread...after 7 years, I still deliver them a "thank you" loaf every week I bake.

I'm really surprised that getting the hydrated lime is a problem...it's available through our (Oregon) Home Depot & Lowes. It may simply be a matter of local terminology or talking to a local masonry worker. Being able to make and use homebrew mortar would be a lot less expensive than the HeatStop (which I also used -$$$$ ).

Don't forget that it will be to your advantage to put in a moisture barrier between the top slab and the hearth insulation board. Also, if you'll be baking bread, you'll probably end up getting a insulated (firing/holding) door along with a lighter (cooking/working) door. Incorporating a thermal break will also help with the heat leakage.

I've used our oven primarily for breads. I normally bake 15-20 loaves on a single firing and have done up to 30. My insulation base was only 4" of 5:1 perlite:cement and I've got about 8" of 8:1 perlite covering the dome. With my marginal insulation, I certainly do not have great, long term heat retention...and I really wished I'd sprung for the ceramic board underneath, but seven years ago it just wasn't in the budget. I've been very happy with the Pompeii oven for my bread and the 2.5" thickness of hearth has worked well baking (primarily baguettes at 575-585F -- takes about 15 min per load).

The one problem I have with bread in my oven is loading. The door width and round floor footprint make "fitting" the loaves into the oven a little difficult. I have settled into baking 5-10 loaves at a time simply because getting to the back loaves (over the front loaves) is a bit challenging. That said, the range of being able to cook a 25# whole turkey or a full sheet pan of biscotti (as well as pizza) is fabulous.

Sorry to be late to the party (and to ramble on with this post...), but I'm looking forward to watching your build progress and hope my input has some value for you.

[Gulf]

On that note, any suggestions on the first course? I'd like to keep it a true half-spherical dome, so am planning on using 1/2 size bricks, standing upright, instead of starting with full brick height. I haven't decided on 'solider' or 'sailor' though. My understanding is that they're standing the same vertically, but rotated 90 degrees depending on the type I lay. I'm leaning towards the sailor course, with the wider side of the brick facing the interior of the oven. Are there any pitfalls I need to be aware of?

I am afraid that you have been a little misled somewhere about soldier and sailor courses. However, if you want to have a "true half-spherical dome" (hemispherical), my advice is to lay the first course just like all the rest. It is a stronger bond and it will work better with your IT, without having to adjust.

[Caliea]

Hi Sable,
Thanks for the real world numbers on baking breads with the insulation you have. That sounds pretty great for what we're envisioning.

Thanks for the heads up in the vapor barrier. We just receivedette our insulating board last night, so that's the next step.

I came home today eager to get some real cuts going. I decided to try the 14" chop saw dry. When I got it home, after digging it out of my Dad's workshop, I realized that it had a 10" metal cutting abrasive blade on it. I gave it a shot, but it's definitely not necessarily option I'm willing to work with. Too slow, still didn't cut through, etc.

I then tried a small grinder with a masonry disc, but again, not a viable option. I was taking the wind out of my sails, as I was running out of options. I decided to give the hammer and chisel a shot. Amazingly, it actually worked well for me. I managed to knock about 20 bricks in (roughly) half pretty quickly, and only had 2 that broke unevenly.

So I scribed a circle on my slab as a test, and laid out my roughly broken bricks. I have to say, I'm pleasantly surprised at how well it looks at the first pass. I'm happy you hear that you did the "no cut" method, as it's looking more attractive to me by the minute!

I've posted pics of my rough layout, and what my bricks look like after my novice chiseling job. Not too shabby, IMO.

I've also posted a pic of my DIY compass. It's a lumber crayon duct taped to an arrow, with a pin pivot point on the opposite end. Very classy - I may patent it later. But it worked for a rough circle on my slab. I'm also.leaning towards using the "String Theory" when laying the brick. I know a lot.of these details may be making some of the craftsmen on here cringe, but I'm making do with what I have.

Gulf - thanks for the clarification on the first course. And I appreciate your restraint in not phrasing that as "you're so, so wrong!" I'm going to just start the dome and carry on then. No special treatment of the first course.

Hoping to at least get a course laid this weekend. Depends on weather and kids soccer schedules.

As always , thanks for your help!

[Caliea]

[Gulf]

Caliea,

It looks like ya'll have got it "going on" .

I decided to give the hammer and chisel a shot. Amazingly, it actually worked well for me. I managed to knock about 20 bricks in (roughly) half pretty quickly, and only had 2 that broke unevenly. I decided to give the hammer and chisel a shot. Amazingly, it actually worked well for me. I managed to knock about 20 bricks in (roughly) half pretty quickly, and only had 2 that broke unevenly.

What type of chisel are you using? Is it a brickset chisel aka bolster? If you haven't already, Do a search for "cutting brick with a bolster". There are some youtube videos on the subject that might come in handy for you. Here is one. There are others. In the video the guy spreads a thin base of sand on a concrete slab. The older I get, the more I am in to ergonomics. The last time that I cut brick with a brick set, I made a shallow square box to hold the sand. I placed it on top of a large butt cut of fire wood. That saved my aches and pains for other ventures.

I'm also.leaning towards using the "String Theory" when laying the brick. I know a lot.of these details may be making some of the craftsmen on here cringe, but I'm making do with what I have.

There are a plenty of easy ways to make a workable IT with no welding. I know that it is in all of us to "go full steam ahead" and to get the project started. But, I think that in the long run, if you will take a breath, and make an IT, you will be very glad that you did.

[UtahBeehiver]

Plus one on IT. You are spending a lot of time and money on this project. You can build a non weld IT for under 10 bucks. It will be worth the effort. Put those engineers to work building one. I have seen some nice builds done with brick bolsters only. You will see what we call an inverted v joint as you move up in courses on the dome. These can be minimized by sidewall bevels near the front or inside edge of the dome. It is possible you may be able to do some of this with your small tile saw or an angle grinder with a diamond cup.

[jonv]

I'm sure a great oven can be built with just a hammer and chisel, and that approach has some appeal to me too. However, I'm trying to cut all of my bricks to fit fairly close; not that I suppose it will make any difference in the end. I have some difficulties, though, as a wet cut saw here with the required depth of cut costs around £750... very envious of those folk that can get one of those harbour freight (?) saws

To make matters worse there are few diamond blades that will fit my chop saw. I eventually found one at a reasonable cost to see if the old saw would cope. So far I have just cut the floor bricks - although these are some of the more demanding cuts from the saw's perspective. I found that soaking the bricks first made quite a difference. So far the cuts seem quite good and not an excessive amount of dust (there's enough and a mask is required but less than I had expected).

Time will tell just how long the blade will last - I expect I'll need a few before I'm done. I'm hoping the chop saw will do the job. At this point I wouldn't rule it out - does need a diamond blade though.

[JRPizza]

Plus 2 for the IT. I think folks have built using string, but the IT allows you to very quickly set the proper distance and angle. I used a clamp which allowed me to mark where the brick was going to sit, butter up the footprint, the press it into place squeezing out excess mortar (needed to use wet mortar). I removed the clamp immediately and moved on to the next brick. By the time I got near the top of the dome I didn't need the clamp any more and just held the brick against the clamp to establish position and placed the bricks. You just need to make sure the center of the IT stick/rod/bar hits the brick at it's centerline. I also had best luck pulling the bracket away from the brick when the mortar was still wet (or very dry) as I found the bricks moved ever so slightly and if the mortar had started to set I could break my bond line (didn't happen if I moved it in first few minutes).

[thevance53@gmail.com]

The IT was the most important device I used in my build. Just a 1/16" off and you develop ledges that throw off future courses. Figure out how to make an IT and stick with it, It is kind of a pain, but makes it easy to keep a circle and avoid the dreaded droop. Mostimportant to tie in the entry arch to the dome.

[Caliea]

Gulf, I honestly don't know what type of chisel it is. It was the most promising looking one after digging through the tool room. Since we're 25 miles from any home improvement store, I gave a quick thought to "I'll replace it for him if I have to", and started pecking away at the brick.

For anyone else following this thread, here's what I did. I measured and marked the bricks in half on both wide flat sides. I then took the chisel and a regular framing hammer and worked my way down the line, giving a whack and scoring it as I went. I flipped the brick, did the same on the other wide side, then placed it over an empty cell in my cinder block wall and gave it a good whack (or 2) with a rubber dead blow hammer. Most (90% or so) broke cleanly. I've attached a pic of the tools I used, along with one brick that split as expected. I used this method to break maybe 25 bricks to get an idea of what the oven would look like. I think it's a viable option for just halving bricks, but I definitely don't have the skills to make any tweaks or precision cuts.

We were in town yesterday and picked up a 14" masonry blade (metal with evil looking edges). It cost $100 (ouch!) But cuts through the bricks with ease. So we made some bevels on the half bricks and will be proceeding from there.

We cut and placed the insulating board and the floor bricks last night. Originally I was planning on cutting the floor to fit inside the dome, but are now planning on resting the dome on the floor. Removes a lot of the curved cuts that would be required for the floor. I'm hoping to get the first course or two laid today, and I can't wait!

Re: the IT - my husband is going to give it a shot. He will fabricate one this a.m., while I start trimming bricks, and we're going to try it out on the first courses to see what we think. We have a caster wheel, so will be making one based on that design. From what I gather, the #1 concern is making sure the centerline of the brick is lined up with the centerline of the arm. Thanks for the encouragement and for providing me a place to gain advice and tips! Hopefully more pictures to post this evening!

[Caliea]

We got 2.5 courses done and lots of thinking/prototyping/ guessing on the inner arch and its transition.

It's not perfect, but I'm pleased with our progress this weekend. Excuse the photo. We ran out of daylight.

[Caliea]

I need help climbing out of the quagmire of arch design that I have fallen into.

Here’s what I am aiming for: an inner arch that intersects my dome “correctly” and provides a stable basis to construct a vent opening and outer arch. For now, I’m concentrating on this inner arch deal.

I’ve built an arch form, and my dimensions are a 19” opening width, with a total height of 14”. (the form is a bit short so I can shim to final height) This may be a bit larger opening than normal, but I’d like to have a good view of the fire from our deck, for when we use it as a fireplace / ambiance.

We have placed the bricks around the form to get an idea of how many and what they will look like. I would like to angle the bricks to lessen the mortar joints. I know this arch won’t be seen much, but I’d like to practice on this arch before we do the outer decorative arch.

My questions are:
1. Do I use full or half bricks to construct the inner arch? I was thinking that full bricks are the way to go, as it allows more leeway for trimming when intersecting the dome.

2. How do I locate the point at which the first arch brick hits the first course of dome brick? If I set the first arch bricks flush with the inside of the dome at the bottom, then by the time I go up a few courses, I’ll be way outside the curvature of the dome,and that i will end up with that egg-shaped distortion that I keep reading about. Or is the answer that the arch bricks just keep getting slightly longer?

3. How do I figure out what the angle is on the arch bricks? I suspect that since my dome cuts are just beveled, and not angled and beveled, that I’'m misunderstanding the cuts on the arch. If I use the dome spreadsheet, can I enter inputs that will give me brick arch dimensions? I’ve attached a picture I stole from RandyJ. It’s a Beautiful arch, but I can’t figure out how to calculate those cuts. The other arch pic is from OctoForno, and looks more similar to my dome bricks, just turned on their sides? Maybe this method is easier?

4. I was planning on constructing the inner arch, then mimicking the method for the outer arch, but making it wider (for a door reveal), and using full length bricks up the sides and transitioning to half bricks at the top to leave a gap for chimney/vent gases to move through. This would leave a 4.5” wide gap (by 15” or so). Is this enough for a 42” oven? I've attached a picture I borrowed from another forum members that shows the layout I'm describing.

I’ve laid the first 3 courses of my dome, but have left the entrance area blank until we settle these questions. I plan on laying out the entrance and inner arch and starting to work on this area this weekend.

I’ve read tons of threads on this, so I swear I’ve put effort in. I just can’t seem to get it straight in my head, and I think I’m getting more confused as I research more.

Any advice would help.

[UtahBeehiver]

Tapered inner arch is a brain twister. This is where an IT really comes into play.

Q1 - full brick required, it will be adjusted to a shorter length but greater than a half a brick.
Q2 - See pic 1
Q3 See pic 2, DJs spreadsheet of for dome bricks not arch bricks. This show a partial arch but the concept is the same for a full hemi arch.

Make sure you shim your arch form with at least 1/2" of release or you won't get the form out.

This concept takes awhile to sink in but once the light bulb comes on it all comes together. It will be difficult to cut these taper bricks with a brick bolster. In order to get even joints on the arch(s) you will need to taper the widths as well.

[JRPizza]

We recently helped one of our members work through arch placement - see posts #26 and 27 in the attached link for some cad sketches I did that show what Russell's pictures are showing in a slightly different way.