42" Pompeii construction in Adelaide

[P3 Stoaker]

G'day All,
Thanks again Russell, and I must say I had a good laugh at your comment, paralysis by analysis, I know it got me !!
I have had some progress, a little slow with competing time consuming requirements. First course down this morning and preparing to lay the second, photo's later tonight.
One thing I've discovered is the inner arch template prevents access to that mortar line to tidy it up/finish it, the long inner line along the inner joint of the inner arch, and will be the same for outer arch I guess.
What did you all do about this? Did you simply tidy that mortar joint later when the template was removed?
Regards

[UtahBeehiver]

IMHO, you will be fine by using a peanut butter consistency slurry of 50/50 fireclay. The difference between the cuts and factory edges cannot be extreme, what are we talking, 1/16 or 1/8"? There is plenty of compressive strength in the slurry and merely acts as a spacer. These ovens are not precise tolerance, you can work yourself into "paralysis by analysis" pretty easy.

[P3 Stoaker]

G'day All,
Thanks Russell / Tom appreciate the feedback.
Pretty much set to lay the first course but its pissing down rain all weekend so I might start next week as looking a lot better.
I'm using 12" square floor bricks and 2 of the cut edge pieces are a little lower which will cause the dome brick to tilt back out of reasonable alignment ( dome on floor). So I thought I'll get some fire clay, start at the highest point without the fire clay and move around the dome, using the fire clay to keep things level. I'm not a person to fuss too much but I do figure the better the first course is the less work later.
When purchasing the fire clay the salesman knew it was for a pizza oven but no detail. He advised me it wouldn't set and would wash away with rain or water. Whilst it shouldn't get wet and I don't plan on hosing it, I do wonder about its weight bearing strength? I know the advice is 50/50 fire clay and sand but I can't imagine sand increasing it's strength. So I'm now wondering if there is a difference in the product here in Australia compared to USA, I know other products are significantly different to the point I'm cautious and like to avoid a disaster.
I might mix some up and do a test.
Regards

[GreenViews]

Greg, If you see my build, I did that very thing. I placed my first course (actually did half solder even) flat on ground, then over compensated with angle of my second course (which for me was also half soldier). That worked out very well for me! I found that adjusting as I went with my template worked very well and I didn't sweat it when one course or another ended up slightly off... I just adjusted the next as I went.... for the last few courses, I stopped using my template at all. The ending became obvious p.s. our ships in life usually never fully sail, the journey just changes course or direction. You got this.

[UtahBeehiver]

As you lay the dome bricks, any corrections such as width, or less perfect bricks place towards the front half of the dome with the best work and brick faces on the back half of the dome, you can only see the back half when the dome is complete and fired up. Also watch to make sure you stagger the vertical joints from course to course, looking on the outside joints of the dome does mean the inside joints are the same.

[P3 Stoaker]

I'm with you Russell, in that mortar is your friend, or in my case will be. I am just getting ready to lay the first course. I'm happy with, and many thanks for all the advice, but just to explain where the comment came from, in regards to the sizeable second course joint, When laying the first course flat on the floor bricks it obviously doesn't commence the dome curve. I assume this means the second course has a larger gap at the outside where it meets the first because the second course, if aligned correctly with the IT tool will take up the gap for the first and second courses, in comparison to the case if the first was laid in true alignment with the IT, and had appropriate gaps at the rear.
Hope that makes sense, either way I'm laying the first course flat on the floor bricks and I will be using a little fire clay for the rear quarter as its a little lower, I plan to start laying at the highest point and keep it level from there. I'm just in the middle of modifying the IT tool with a fork bolt at the bottom to better align with true floor level.
Kind Regards

[UtahBeehiver]

Tight inner joints is what you are after, backfill the sides and back with mortar. I am a little surprise that you say the second course has a sizable horizontal gap, what do you consider sizable? You never see the back side one all said and done.

[P3 Stoaker]

Thanks Russell, apologies for confusion, I meant to say floor bricks rather than Casil.
I'm laying first dome course on the floor bricks as a header, it's a tapered half brick though and I suppose my main question was whether it's lifted at the back so as to start the 'dome curve'. As you say just lay it flat on the floor brick and mortar the side vertical joints. I guess that means as the second course is risen at the back to align with the IT it will have a sizeable gap to fill with mortar?? As you say mortar is your friend.
Regards

[UtahBeehiver]

I am not quite sure I follow, Second sentence say dome "On Top" firebrick, which a fine. Then second paragraph talked about first course on CaSi or do you mean floor brick. Bottom line, The horizontal joint between the floor and the first course is NOT mortared, the vertical joints are. This is done so the dome and the floor expand and contract more independently and reduce potential cracking issues. No sand/fire clay need since floor appears level,

Fire clay sometimes call "brickies clay", it is powdered clay. Can also be found at pottery stores as well.

[P3 Stoaker]

Also, meant to ask, doesn't seem to be much around home when searching for fire clay. Might be called something different here in Aus? Has anyone found any and what was it called?
Can anyone tell me what it's made from, and the rough ratio's? I'm concerned I'll be told something is fire clay but it may be something all-together different?? If I know what's in it I can check it's the right stuff.
Regards

[P3 Stoaker]

G'day All,
Thanks Russell. I hope to start the dome soon, which will be dome on top of the floor brick method. The Casil is level and the floor bricks quite even so I hope not to need fire clay under floor bricks. If I do I recall 50/50 fireclay and sand.
What I am wondering about is I have read many times, ' do not mortar the first dome course down, use fireclay if necessary'. In the end mortar between the bricks will obviously be required which has me thinking about this first course, do we sit the first course up at the back, properly aligned by the IT tool, (mortar or fireclay would be required) or should it be laid flat on the Casil without mortar, except of course mortar between the bricks will be required.
Clearly, I don't have this bit sorted, any assistance/comments will be greatly appreciated.
Photo below for info, shows the overall level surface, perlite surrounding the Casil board.
Regards

[UtahBeehiver]

1. You only need fire clay/sand under firebrick if one the CaSi board needs leveling or two the fire bricks have various thickness and also need leveling. If everything is flat, no need.
2.Yes and Yes,

[P3 Stoaker]

G'day All,
Progress a little slow, eldest son's 18th with family last weekend and his mates for bonfire next weekend, yes, two 18th's, thanks Covid!!
So I recently filled the side area's of the Pizza oven base with perlite concrete, mainly as it's lighter and easier to work with compared to normal concrete. Mosaic tiles on the bottom and 3 by 1 inch layers of casil board on top. (photo's 3-7) I hope to start the dome soon. Will appreciate thoughts on a few things;
1 I've read plenty, lay the first dome course on the oven floor on fireclay. Can/should that be thick at the back in order to start the dome arch? In line with the IT?
2 I'm looking at using a tapered half brick for the dome. Initially for the lower dome courses they can be lay'd offset as per photo 2 and when the curve begins to sharpen they can be lay'd as per photo 1. What do you think? Has anyone seen or used something similar?
Kind Regards

[JRPizza]

It looks like you have your arch location well dialed in. It will be fun to watch your build progress!

[P3 Stoaker]

G'day All, Some progress today. Made another arch template and worked out the taper arch cut position on TDC (photo no 1). No actual brick in the photo as I couldn't hold the brick and take the photo. I think the IT and lines drawn give the idea. At the moment I have a caster at the bottom of the IT but I believe it is quite accurate as it sits in the photo. I have a fork bolt and I'll improve the IT before I get into dome works. Given TDC sort of governs or effects the position of the lowest arch brick I was keen to get this finalised so I could cut the floor tiles, (photo 4 and 6). The tiles are 12" square by 2" thick and the size made the whole cut process quite easy, as best as I can tell anyway not having built an oven. The floor is 1" larger than the dome all around just to spread the load. Possibly not needed but easy to do so went for it. Photo 5 jumped in there, an open fireplace adjacent the pizza oven. The blue board will be rendered ( I think called strucco in the US) to match the pizza dome render.
I previously posted in 'tips' but for those that didn't see it and are thinking of using Mosaic Tiles under Casil board, DO NOT LET THEM GET WET. The glue holding the netting dissolves quite quickly when wet, meaning they can only then be moved as individual tiles, not good !!!! Less than half got wet and luckily I have a lot of extra sheets and managed to salvage some of the wet one's by getting them on sheet metal. I think the glue has reset but also to the adjacent sheet as well.
Has anyone heard of or used waterproof perlite? I'm wondering if it dries quicker. I'm only using the perlite to build up/fill the area's beside my dome but would be handy if it dried quick. The description says "LiteFill Perlite is treated in a solution to give each particle a waterproof coating".
Kind Regards
Greg