42" Pompeii construction in Adelaide

[MarkJerling]

G'day All,
Hope everyone is going ok in the crazy climate in which we live. I recently travelled overseas with work and therefore had to complete 2 weeks hotel isolation once back in Australia confined to the room. Had its benefits though, I knew when I got home I'd be super busy for, well months really. I think I'd be happy with a weeks isolation ( forced rest) every month!!
So the build continues, many thanks to all for the terrific advice and assistance along the way, it's made a huge difference.
Things are getting seriously steep now. I've been quite surprised though, resting the brick in the IT tool for just a few minutes is all that's required before it can be removed and the brick stays in place. I'm not yet vertical but it's not far off. I think the next level will require longer support. Also, tapping the brick down in place, whilst in the tool, I think that helps. I made the IT tool with a clamp but haven't as yet fitted it and I don't think I will, just not required.
Up until now after laying each brick I have reached in, tidied up the mortar and wiped the face clean with a sponge. Very soon I will not be able to do this. I expect the inside to be a mixture of joints with spewing out mortar and joints requiring additional mortar. A similar thing to photo 1 and 2 where the inside of the dome arch couldn't be accessed. If able I'd appreciate comments on what you did to deal with this issue?
One other question relates to the flue. I plan to have a flat metal base plate fixed to a horizontal brick surface, above the vent arch/vent. I was talking to someone who raised two concerns about this plan and I would appreciate any thoughts comments regarding,
Firstly, assuming some sort of brick bolt/screw fixing, the metal plate and bricks would have vastly differing expansion/contraction rates. I wonder if sitting the plate on some insulation type material and having large holes in the plate would allow the necessary movement?
Also this chap has concerns the collected water running down the flue will eventually run into vent brickwork which will soak up water every time it rains and when fired up will mean significant drying of the bricks, possible quite often. Has anyone experienced/heard of this as an issue?

It's great to be back, thanks for reading my post and good luck to you all.
Regards
Greg

Your oven is coming along nicely. Well done! I note your comments with regard to a deep entry arch. Feel free to look at my build drawings. My entry arch is quite deep and I find that it works very well. But then, I did make my own tools with decent length handles! LOL

[david s]

I'd be dampening the area where the crack is so it's damp not wet then trying to rub some mortar into the crack. Try sieving out the coarser sand from you mortar first so it's really fine. The crack will probably reappear when you get around to giving it some decent fire so don't worry over it too much.

[UtahBeehiver]

I would call that arch crack a beauty line. The mortar joint is a little thick on the outer edge but IMHO I think you damage would be done by replacing joint or adding a voussier. Full arches are self-supporting.anyway.

[P3 Stoaker]

G'day All, little reply to my previous post, not sure if they're being read. I'll give another post a try and look at the counter on the front page this time.
Progress today, I have removed the IT tool and I have a little timber plate up under the rather large plug hole and a large 2 piece plug cut ready to finalise the dome tomorrow. I have been quite surprised as its only been the last 2-3 rows that have required a little support once the bricks are in, and after just a few minutes the IT tool can be removed.
I wanted a quick and easy way to get the mortar fully in the joints where, like on the last brick of some rows, you cannot hammer the brick down in place. So I got a large syringe (photo 2) and happened to have a suitable size piece of thin plastic tube (happened to be shrink wrap). This allowed me to push the thin tube all the way in and fully fill the joint with mortar, quickly and easily, with the brick simply sitting on the IT tool.
I had a large slab of timber in the place of the 2 cleaner looking floor pavers (photo 3) upon which the IT tool was fixed. I was glad to see the floor pavers (actually fire brick) fitted back in the hole. Whilst there was no reason they shouldn't, I did wonder if anything moved !!
I do have one question for anyone that can offer feedback. I realise these type of ovens will develop cracks and I'm not concerned about that. Question is do certain types, size, location of cracks justify any sort of repair? I have a small crack at the top of the dome arch and whilst its minor I can access it now. I wouldn't wand to cover most of this minor crack with the vent arch if later i'm advised I should have taken action while I could, whilst I had access.
So I should pass the significant stage of plugging the dome tomorrow, and then onto the vent arch.
Regards to all.

[P3 Stoaker]

G'day All,
Hope everyone is going ok in the crazy climate in which we live. I recently travelled overseas with work and therefore had to complete 2 weeks hotel isolation once back in Australia confined to the room. Had its benefits though, I knew when I got home I'd be super busy for, well months really. I think I'd be happy with a weeks isolation ( forced rest) every month!!
So the build continues, many thanks to all for the terrific advice and assistance along the way, it's made a huge difference.
Things are getting seriously steep now. I've been quite surprised though, resting the brick in the IT tool for just a few minutes is all that's required before it can be removed and the brick stays in place. I'm not yet vertical but it's not far off. I think the next level will require longer support. Also, tapping the brick down in place, whilst in the tool, I think that helps. I made the IT tool with a clamp but haven't as yet fitted it and I don't think I will, just not required.
Up until now after laying each brick I have reached in, tidied up the mortar and wiped the face clean with a sponge. Very soon I will not be able to do this. I expect the inside to be a mixture of joints with spewing out mortar and joints requiring additional mortar. A similar thing to photo 1 and 2 where the inside of the dome arch couldn't be accessed. If able I'd appreciate comments on what you did to deal with this issue?
One other question relates to the flue. I plan to have a flat metal base plate fixed to a horizontal brick surface, above the vent arch/vent. I was talking to someone who raised two concerns about this plan and I would appreciate any thoughts comments regarding,
Firstly, assuming some sort of brick bolt/screw fixing, the metal plate and bricks would have vastly differing expansion/contraction rates. I wonder if sitting the plate on some insulation type material and having large holes in the plate would allow the necessary movement?
Also this chap has concerns the collected water running down the flue will eventually run into vent brickwork which will soak up water every time it rains and when fired up will mean significant drying of the bricks, possible quite often. Has anyone experienced/heard of this as an issue?

It's great to be back, thanks for reading my post and good luck to you all.
Regards
Greg

[Baza]

Looks FANTASTIC - I struggle with the fear of too much mortar showing in the interior and I know it is brick over mortar for the interior - but I think there has to be some forgiveness (I sure as hell hope so!) to give us some permission for leeway! The thing will still cook a mean pie!
Great job, mate - looks like a solid clean build.
Barry

[P3 Stoaker]

G'day All,
I had to stop work around 3 weeks ago and I've been meaning to update since then. Unfortunately work will prevent any chance of continuing the oven for the next few months.
A huge thanks to all for your comments and assistance so far, certainly results in not only a much better result but no doubt quicker as well.
It was good to at least close the dome off over the inner arch before I stopped. I'm still not sure I really grasped the tapered inner arch, I think it was a lot of luck but I do know the assistance from forum members informed me enough to get the position of the arch reasonable which was the main thing.
I purchased the dome bricks as is, tapered. The benefit for me was they were available, for the same price as square bricks and have reduced cutting. My old petrol brick saw probably wouldn't make it through cutting all the dome bricks and I had little appetite to do so, so these bricks became an obvious choice. I'm not too fussed with some mortar joint on the inside, I've kept it neat so hopefully all will be fine. Main thing that has caught me out with using them is the joints aligning. Difficult to predict and as you can see quite a few vertical joints have aligned, despite attempts to avoid. Even though I'm only mixing very small batches mortar there is still the need to get on with it and by the time I get bricks wet, height, square, aligned etc etc, well the bloody joints caught me out, a number of times. I can only hope this wont become a significant issue.
As you can see, row 6 is where the switch happened, all bricks are then the same way up. I'm not sure how they will go for the higher rows?
Regards to all, and thanks again.
Greg

[UtahBeehiver]

My build ranks right up there in slowness. I started in 2011 and barely put the finishing touches on in 2021 and only because I needed a Covid 19 stay at home project..LOL.

[P3 Stoaker]

Thanks BeanAnimal, and thanks to all for the feedback. In the end I drew accurate lines in the arch form, where the centre of the arch brick needs to be and I'l aligning that with a centre line along the centre of the brick. I'm keeping the gap required at the inner joints and then simply aligning the brick line with the form line. To be honest I still don't know why the measurements of the required gaps based on the circumference (mathematical calculations) didn't work but oh well pressing on anyway. So getting there around work and other things requiring time. Is there a comp for the slowest build??
Regards

[BeanAnimal]

As mentioned above, the center of the brick face is what needs to be touching the form. So, less wedge angle for each brick.

[P3 Stoaker]

Thanks Russell. Certainly makes sense what you are saying, but achieving it, or importantly why I'm not is the question. The first brick is square and not tapered, 75mm (2 61/64") thick and the bricks above that I'm planning to use are tapered, with the same size at the back, or outside of the arch and reducing to 65mm (2 9/16") on the inner face. As detailed above I positioned that lower brick and started the arc above the floor. For info, given all the advice is that the radius of the arch width along the bottom, across the arch is shorter than the height required what is the common way to combat that ? ( some measurements in posts above). What I did was to start the arc at the top of that first brick which meant the radius width and height worked, but as described the height was lifted by the lowest brick thickness which is why its a square brick.
So currently working through, do I cut it all out, or continue where I'll likely have a wedge at the top as a result of not opening the gaps at the back to the required 24mm.
I'm going to run into the same issues with the outer arch so understanding this will be important sooner or later, might as well be now. Many thanks for your ongoing assistance.
Kind Regards

[UtahBeehiver]

I agree with JR that prelaying out the full arch is you best bet. I also believe the issue starts with the first arch brick, the face is not perpendicular to the center of the arch but rather tipped up too much. Mark the center point on the face of the brick this should be the contact point on the form, not the edges of the brick.

[P3 Stoaker]

Thanks JRPizza. Initially I was going with a lower inner arch and I did dry lay which worked perfectly. I then thought safest to stick closer to the 60 odd % ratio and raised the arch, using a new form for which I didn't do a dry lay. I've just now removed the form and tried a dry lay which has the same problem. One issue I previously looked at was the inner arch height (radius) needs to be taller than the radius of the arch width, according to all the guidance. I assume everyone works through this, did anyone have the same considerations? So the arch height is 315mm (12 inch and 13/32) and the radius of the width is 240mm (9 inch and 29/64). So what I did which may be the problem was to essentially start the arch radius around 3/4 the way up that first brick which was layed on the oven floor.
Another possible problem may be the bricks I'm using. I've worked out the required gaps along the inner and outer to be around 3.25mm (1/8") and 24 mm (15/16"). The bricks are already somewhat tapered but it seems that opening the back up to 24mm causes the inner edges to be mis-aligned and yes that lower brick is not tangent to the form, but seemingly cannot be when the back is set to the required gap.
The only thing I can think of so far is to reduce the outer edge gaps thereby improving the inner alignment which will most likely require a wedge at the top. A little disappointing given bot too much of the brickwork is ever seen and the arches definitely are seen !!
Any thoughts/comments on how to solve this will be greatly appreciated.
Kind Regards

[JRPizza]

P3, I'm a big fan of laying out the arch flat on the ground to make sure you know how it is going to look. If it is not too late I'd encourage you to do similar to the pic I attached. If you do this you can probably come up with a better way to space the bricks and index them to your form. At the very least you need to make the center line of the brick tangent to your form, which the lower bricks don't appear to be. This also requires your form to be a nice smooth circle.
As far as mortar goes, I had the same problem and all I can say is try to butter up enough mortar that you can see the joint being filled and the mortar squeezing out as uniform as possible - you have visibility on the lower rows. Then try to do same on upper rows. I had to go back and do some grinding and filling after I pulled my form.

[P3 Stoaker]

G'day All,
I've run into a bit of an issue with the inner arch which is causing a few headaches. In addition to the question above in the last post I have also discovered the inner edge of the arch bricks are kicking out and therefore look stepped. To be honest I'm not not all that fussy but I will try to get things looking reasonable, and the misalignment looks worst than the photo shows. In photo no 1 you can see how the lower edge of the next brick kicks out in relation to the brick below. Any thoughts on why or how to fix would be appreciated. I don't really want to continue as the stepping may get worse ?
Few other photo's of progress.
Kind Regards