Another WFO in the UK - 42" Pompeii

[WarEagle90]

Hearth stand looks good, Brad. I think you mentioned you were going to do a decorative arch around the opening. If that is the case, you could always pour an arched lintel as part of the hearth slab. There are several builds that have done the lintel that way including my lower slab opening. There are a couple photos in the album linked in my signature of the arch form I used. Unfortunately, I do not have pictures of how I formed up the back side but, looking at your work so far, I think you have the skills to figure that part out. Your IT is well made. The only suggestion I would have on it would be to change how you have it connected to the hinge. If you remove the tubing from the hinge, fold the hinge In half and rotate the tubing 180 degrees in the horizontal plane and reconnect, you will eliminate the issue with it hitting the plywood. Well, I guess since you have already removed part of the bottom of the tubing, you will need to spin the tubing 180 degrees around it’s long axis, too. You could also consider removing the center brick on the floor once you get to that point and constructing a “wooden brick” to put in its place during construction. This gives you the ability to adjust the height so the center point is closer to the dome floor. Just food for thought. You certainly can build the oven with the current configuration of the IT. There have been many on here that have done so with great success. Looking forward to watching the build progress.

[brad mole]

Looking great so far. NIce and neat work so I am suspecting you are a perfectionist or engineer or such. A possible mounting IT mounting option is to make a wood block the is the same size as a floor brick the you can adjust the pivot point to be at floor elevation (Gulf did this on his build). Where you see issues with off the floor elevation pivot point is if you do a tapered inner arch (recommended) as you go up the raidus distance changes so you have to make length adjusments in this area (which I did). So it is up to you.

thanks UtahBeehiver! you would be right in thinking i am a perfectionist, things take so much longer but the satisfaction in getting things done right, and neat is worth it! i had considered the wooden block to act as a floor brick but im worried that when i come to replace it with the real firebrick that it would not fit in perfect and flush, is this a problem that occurs? because id imagine its a one shot deal when you drop that brick in and it is not gonna come back out easily? I do plan to do a tapered inner arch so i may well look into that actually.

Hearth stand looks good, Brad. I think you mentioned you were going to do a decorative arch around the opening. If that is the case, you could always pour an arched lintel as part of the hearth slab. There are several builds that have done the lintel that way including my lower slab opening. There are a couple photos in the album linked in my signature of the arch form I used. Unfortunately, I do not have pictures of how I formed up the back side but, looking at your work so far, I think you have the skills to figure that part out. Your IT is well made. The only suggestion I would have on it would be to change how you have it connected to the hinge. If you remove the tubing from the hinge, fold the hinge In half and rotate the tubing 180 degrees in the horizontal plane and reconnect, you will eliminate the issue with it hitting the plywood. Well, I guess since you have already removed part of the bottom of the tubing, you will need to spin the tubing 180 degrees around it’s long axis, too. You could also consider removing the center brick on the floor once you get to that point and constructing a “wooden brick” to put in its place during construction. This gives you the ability to adjust the height so the center point is closer to the dome floor. Just food for thought. You certainly can build the oven with the current configuration of the IT. There have been many on here that have done so with great success. Looking forward to watching the build progress.

Thanks WarEagle90, that sounds good i may look into doing that, il check a few builds out as well as yours and see if i can figure something out. as for the IT, i will keep playing with it to see if i can come up with something closer to the floor based on what you mentioned, thanks for the advice!

[brad mole]

So ive managed to cut some reinforcing mesh and bar for when i come to pour the hearth, i also made a lintel to support the overhanging concrete above the log store, i just welded it up from 2 10x50mm flat bars and drilled some holes to locate it over my rebar, which should act as extra strength too. Fits great! I also made a framework to support the hearth while it sets up, i just need to find some material to board it out with then im ready to put it all together ready for pouring!

[Gretsch]

Looking good, don't forget to put some shims under the frame supports so you will be able to get it out when your slab sets

[brad mole]

Looking good, don't forget to put some shims under the frame supports so you will be able to get it out when your slab sets

Thanks Gretsch yeah i managed to remember the shims but good to have a reminder as it would be a huge pain to remove without any.

So i cut the board to support the hearth and got it screwed to the framework, i cut it from a gloss melamine material so it would release easier, but i also oiled it too to be extra safe, started installing the props and got it mounted inside sitting nice and flush, taped the gaps then added more supports underneath to be super sure it would hold the weight

[brad mole]

Next i mounted in my steel homemade lintel which you can see spanning the opening mounted over the rebar. I then cut the re enforcing mesh which i had double what i needed so i just put 2 layers in, then also added some 12mm rebar lengths in each direction then tied it all together, seemed a bit overkill but i had the material there so i thought it may as well go in. Next up was cutting the boards to form the side of the former, this was done from 200mm wide boards screwed together then propped up and leveled on more timber props, then i siliconed all the edges to stop any leaks. I held it all tight to the stand with band straps, so now we are ready to pour the slab

[brad mole]

So i finally got the concrete poured in the top, around 0.75 cubic metres was used, the slab is around 150mm thick, heres a few progress pics, it seemed to level off nicely right up until the last pass then i messed up halfway and started tamping again from halfway instead of making a full pass from the start, it all seemed level at the time but after i took the forms off and checked it it is perfect from to back but side to side it drifts off around 5mm at each side, now im going to put 100mm calsil board down first then my floor bricks, would i level off before the calsil board or after, and with what? thanks for any help in advance guys

[Unknown_element]

Looking good!

[brad mole]

Thanks Unknown_element, i finally ordered all of my firebricks and insulation, feels good to get that ordered. So i moved on to making my dome template and IT.

I ended up remaking the IT 3 times as i had something in mind but it just wasn't going to work with the first ring of bricks. Following the centreline all the way through from the pivot to the centre of the brick meant that the box section i was using was hitting my ply base before it allowed me to touch the first course of bricks on the floor. so i ended up cutting the box section in half and welding it to another piece to give me clearance underneath. My IT is made using a butt hinge at the pivot end where i cut off one of side and welded a threaded bar which then goes through the plywood and has a nylock nut holding it on the underside, i couldn't figure out how to get my pivot any closer to the floor level but its only 9mm off so surely thats not too bad? The other end of my IT is an adjustable length threaded bar with an L section arm where the bar is fixed at the centre point of where the brick will sit. I tried to be as accurate as i could just as a challenge to myself im sure it doesn't really need to be so accurate.

I also CNC cut my dome template and arch former because why not?

[brad mole]

My little (big) jigsaw puzzle fits together! here it also shows my other 2 ends for the IT i made, a narrower one for when i get high up, and a pencil attachment for marking out cuts. Screwed the arch former together and tested it in place, fits perfect, dont worry i haven't forgot the packer underneath (well i did forget but remembered as soon as i packed up for the night). Ive marked out on the arch where each brick should lie so that should help me get a neat arch.

Im pleased with how progress is going at the minute, next is to make a jig for the saw to allow me to do the angled cuts

[JRPizza]

Very nice work! I like the way you offset the end down to get the IT centerline in the proper orientation. I'm also jealous that you have CNC capability

[UtahBeehiver]

On thing you need to check on where the "L bracket" and the rod intersect is that this point will be at the vertical center of the brick. If not, the brick will not be perpendicular to the center of the dome. If this happens, the error is cumulative over the courses and the gets worse as you go up. By the way, cool plywood templates.

[brad mole]

Thanks JRPizza!

Russell i have set the intersection point 32mm down from the inner top corner of the L section as my brick are 64mm, it may look out of proportion in the picture, i think its because my L section doesnt have the full 64mm height on the inner side

[UtahBeehiver]

Then you are golden. This IT has to be one of the best machined and fabricated on I have seen. If your oven build reflects this quality then we are in for a treat.

PS on the arch template, when you install you need to add about 1/2" release or shim on the bottoms or you can't get the form out after the arch is complete.

[brad mole]

Thanks Russ. I cant promise anything special on the brickwork side of things as ive only laid any bricks once to build a little wall in the garden. Woodwork and metalwork i can do though so im excited to make some oven tools. Yeah ive just been out to put some packers under the arch former so im good to go when the bricks arrive.