Build started on 36" Pompeii in Socal

[NCMan]

Re: Build started on 36" Pompeii in Socal

That is a long standing debate on here....how to dry an oven. True, it's done both ways. Successfully. I dried mine out w/the insulation off and it did just fine. I will continue to do it that way in the future on other ovens. The trick is to go slow and easy.

[oblertone]

Re: Build started on 36" Pompeii in Socal

I 'cured' my oven without insulation; actually I used it for a year before adding insulation, render, vent arch and flue but logically leaving it bare must allow the water to be driven out more effectively. You just have to ensure it doesn't get rained on during the process.

[RandyJ]

Re: Build started on 36" Pompeii in Socal

I am not going to tell you that you have to do it that way. That is what I did. I know people do it both ways. If you do it before insulation then make sure you start off with charcoal to have a more steady and control able heat source. I was worried about the thermal differences being grater causing cracking so I insulated first. But I am sure others will chime in on there views.

Randy

[kallipigous]

Re: Build started on 36" Pompeii in Socal

Ah I thought not insulating would help the water escape. So you think insulating first?

[RandyJ]

Re: Build started on 36" Pompeii in Socal

Congratulations on plugging the dome. It is a great feeling. I chose not to cure till after I insulated. I figured it would help even out the heat and reduce cracks.

Randy

[kallipigous]

Re: Build started on 36" Pompeii in Socal

Well It's done. It's been quite a weekend. The last two rows were tough as the angles got so weird for me but it's also pretty forgiving because they represent so little weight in the grand scheme of things. I was struggling with what angle to use and was wasting bricks so I went back to the spreadsheet and worked things out by hand based on my measurements of the height and diameters and it began to come together. In a perfect world they'd all slot into place with carefully calculated angles but the positions from bricks on previous levels dictate very much how the subsequent layer's corner bricks sit and this meant I had to do a lot of tweaking to get it close enough.

For the last two layers we gave up on our hard-working I.T. and put the exercise ball in. This was great but it bulged upwards more than I wanted. The diameter of the ball (75 cm) is so much less than the dome so I ended up cutting out a disk of stiff plastic (the top of a container) that was about 2 inches larger that the diameter of the hole that was left and stuffed it between the ball and the roof. At the edges it had no choice but to follow the curve of the bricks and this helped squash the ball's curve to something more like the curve of the dome itself. I had to still use shims but its was a lot closer.

For the keystone I coped some of the the other builds and made it in two halves that I stuffed in together. I was dreading this but it turned out ok and probably only took me half an hour or so to make. I just kept grinding bits away till a couple of taps got it in. The final levels are a little rough but I don't think they're going anywhere. I have to say it's a huge relief to get it over. I've been dreaming about cutting bricks for weeks so now I'll have to dream about building the chimney and the insulation but that can wait for a few weeks till I've cured the oven. Of course it may fall down when I'm curing but for the time being it looks good enough think.

Many thanks to everybody for their very kind help. It really would not be possible without this forum.

[kallipigous]

Re: Build started on 36" Pompeii in Socal

Next layer done. Getting there ever so slowly. Obviously if you inspect closely you'd find lots of weird holes here jammed with triangular offcuts of brick - but overall I'm happy. We're mainly level all the way round but the front part over the dome is a quarter to a half inch lower so we're slowly making that up with little wedges as we go round. I'm guessing now there are so few layers to go the weight doesn't matter now so as long as they are mortared reasonably tightly we're ok.

I'm finding getting one angle cut to work pretty tricky so we tend to do a run of three or so bricks and then find the next one can't meet without creating a quarter inch v so we leave an exaggerated gap of an inch or so and start again. Then at the end we go round and fill the gap with whatever odd shape brick it takes to to get them to match. I trace the front and back hole on bits of paper, cut the paper out and use both ends as a template to draw on the brick. Connect the lines, cut and you have a weird but nicely fitting brick and all you badly cut angles go away.

Oh and the 3d printed wedge? Not worth the effort. I'm back to chipster's jig but I've removed the bottoms as I've not enough headroom now. It worked on the earlier layers but the angles are so acute now I need to keep adjusting.

[kallipigous]

Re: Build started on 36" Pompeii in Socal

We're a mixture of both. Sometimes it's mortar and sometimes we have to tap them in place as the FB pdf says. But I was just nervous that that's where the stresses will be when they all expand. Do we know how much these bricks do expand?

Good luck gastagg. It's a good feeling when you get there - even if we are a little wobbly.

[DavidApp]

Re: Build started on 36" Pompeii in Socal

Hello Kallipigous

I did not have to Jam any bricks into the dome. There was always mortar between the bricks even on the plug bricks. On some occasions I had to do a bit of resizing when I mortared the brick and found that it would not fit.

Best regards
David

[gastagg]

Re: Build started on 36" Pompeii in Socal

You're just ahead of me kallipigous...can't wait to get past these arch cuts.

[kallipigous]

Re: Build started on 36" Pompeii in Socal

Ok it took 4 hours but we did the next layer and we're over the hump
(literally). Not as level front to back as we'd like but they are locked in and hopefully we're now in the final furlongs.

[kallipigous]

Re: Build started on 36" Pompeii in Socal

Yeah I think your'e right/ I'll leave it in the sun next week while I'm here then I can run out if things get weird.

[GianniFocaccia]

Re: Build started on 36" Pompeii in Socal

Safer to throw a tarp on it so the wind doesn't blow it off. The sun will radiate heat into the oven and moisture will find its way out. If you leave it exposed and the rogue rain (I'm 17mi south of you) shows up, you're back to square one.

[kallipigous]

Re: Build started on 36" Pompeii in Socal

Couple of questions. I was thinking about this jamming the last brick in to lock the layer. Does this not make it more likely to crack when the oven heats up? I would have thought a little bit of movement sideways would be good to allow for expansion and contraction?

Secondly. We're going away at the end of next week so that's a great opportunity to let the oven dry for a couple of weeks before we start curing. Would it help to leave the oven in the full Californian sunshine while we're away so it dries out more, or should we keep it in the shade? It's unlikely to rain in late July so I'm wondering if the hot California sun might be a nice way to start that slow curing process. The only difference is that it will be heated from the outside.

[kallipigous]

Re: Build started on 36" Pompeii in Socal

Ok that's useful actually as I have a lot of bricks I over cut before that I can cannibalise for the skinnier ones. Excellent advice many thanks.