39" Stargate Pompeii

[Amac]

Re: 39" Stargate Pompeii

Hi Dennis
Slow but sure will win the race - and so far you are doing the right thing - it is looking good. If I had to do again I would take more care on the slab - but you are right it is not a race (except against the weather here - today rain stopped play again).

For the arch/dome transition - I am planning to take the approach shown in the 4th picture down on this site for the last row.

translate from the dutch (google made us all multilingual)

The back of the arch is clearly visible. As you can see the shape of the stone is quite complex, but not so impossible.

The idea is that the sixth row of bricks there will soon run smoothly over it. As mentioned, the tailoring of the arch stone is the hardest drawing

I like the shape of the arch with vertical sides = but after seeing Johns (Giannis) Aceves, Karangi Dude, Sharkey and some others, I realised that the semicircular arch in a hemisphere would allow me to cut all the arch bricks to the same pentagonal template which I could work out in advance.
This is why I chose the method I used. I used a radius of 10.5" raised 1.5" from the floor giving me a dome entry height of 12". I also raised the dome 1.5 inches to maintain the arch/dome integration. The IT has to be raised 1.5" to match these.

The attached drawing shows how I cut the arch (using a life sized version). The shaded pentagon on the left is the correct shape for that combination of dome and arch..

There was a lot of discussion on this with Gianni etc over at aceves thread.
http://www.fornobravo.com/forum/8/ac...d-16501-6.html
I am sure those guys are bored with it by now

So far it is working out as I expected. I cut the arch first and built the arch first and it ties in smoothly enough to the dome. Still have to fight the "droop" as you get higher up the arch but I think it will be OK.

It will be a bit short of the 63% ratio opening to dome but I am not sure if that is a big issue judging by this comment from James on the "Opening size" thread:

Opening height does depend on dome height, and 60% is an OK rule of thumb -- though it is something of an urban legend. There is no perfect formula, and I have never seen it used in the context of an Italian brick oven. For example, the ancient ovens have really high domes (you can almost stand up in them), so the opening height to dome height ratio on those is tiny. Equally, as brick ovens gets larger and the dome gets higher, there is no reason to make the opening taller than 12"-13" -- the size you need to get a roast in and out. So in that case the ratio of opening height to dome height gets smaller and the ovens simply perform better.

If you have a 42" oven, with a 20" dome, an 19"W x 12"H opening should work nicely. Good access, good thermal characteristics.

If you have a 36" oven with a 17"-18" dome, an 18"W x 11"H opening would be good.

If you are building a Volta Bassa (low Naples style dome), you should bring your opening down an 1" or so -- but makes sure you can still fit in a turkey.

If you want to maximize heat retention, you can always arch your oven opening (higher in the middle for a roast), but lower on the sides for heat retention

I feel I am close enough to that - except the 20" limit to the width - but

Anyway Dennis judging by the quality of the work you have done on your oven area and slab - I would say you will do a good job on the dome also. I find myself taking a bit more care when I feel I have to show my handywork to the forum members. Mind you they will never be too critical - all that stuff is "between the lines" as it should be

[GianniFocaccia]

Re: 39" Stargate Pompeii

Mind you they will never be too critical - all that stuff is "between the lines" as it should be

And not too soon after covered completely with soot.

[Amac]

Re: 39" Stargate Pompeii

A couple of really nice - definitely spring and almost summery days - so I got some work on row five done and am now over the arch. It turned out better than I expected I simplified the cuts somewhat.

There were 4 brick pieces need in row 5 to complete the arch transition.

Two pentagonal shapes which were fitted first.

To fill the gap shown in the first photo I cut 2 brick pieces. First I cut a half brick, the cut angled a little. I then sliced it in two flat pieces.
Aidan
PS
I totally forgot to do the Sharkey "load test" on the arch before I covered it - when those bricks have set I will have to hoist these creaking limbs onto it.

[GianniFocaccia]

Re: 39" Stargate Pompeii

Aidan,

Your transition looks magnificent. It has that curve that flows smoothly into the dome. Beautifully crafted! Uh, your patio rocks too. Nice job.
John

[Amac]

Re: 39" Stargate Pompeii

Your transition looks magnificent. It has that curve that flows smoothly into the dome

Thanks John - I owe a lot to the study of this brick - you might recognise it
patio is not my work - I think I would be a bit more cofident about taking on those jobs now with my growing expertise with the angle grinder
Rain is back
Aidan

[Amac]

Re: 39" Stargate Pompeii

Rain cleared yesterday afternoon and I managed to get row 5 complete and 1/2 row 6. Starting to get really steep but bricks are holding well after a minute or so gripped by the IT. The inverted Vs are a problem so I bevel each brick but never quite enough but I think they are OK.
I have started to cut the bricks in three as shown in pics. I am using the outside ends in these rows and I hope the middle pieces will be good for the second last or last row.
Oh and a picture of the trees through the dome - for ...well for artistic effect
Aidan

[Laku]

Re: 39" Stargate Pompeii

With 3rd cut you could get two "perfectly" fitting bricks and one that might be usable later and one scrap.

[Amac]

Re: 39" Stargate Pompeii

Hi laku
Right now I get two usable bricks - the end pieces - I have to flip one of them so the widest part is at the top. So I can work in one direction with one end piece, and in the other direction with the other. Where they meet just needs a little more cutting.
The centre piece as I said should be suitable for the tighter rows near the top of the dome. I have seen some very similar. They will not of course be perfect.
I'm not sure if I explained that well but I prefer to use as few cuts as possible.
Could you post a photo or drawing to illustrate.
I think Aceves was making 4 cuts to get three usable and two scraps.

[Laku]

Re: 39" Stargate Pompeii

Certainly. Here's a link to a post where I've explained (with picture) how I cut my brick explanation picture

Basically the idea is the same as you've done except that' I've used third cut similar to the ones you've done in the middle of your brick. That way you get two tapered bricks and a scrap, which will get larger as your chains get smaller.

[kpms1st]

Re: 39" Stargate Pompeii

Hi been following your progress like the look of your arch .Am down in Kilkenny and nearly finished a 36in kpm

[Amac]

Re: 39" Stargate Pompeii

Hi kpm - Great to hear another oven going up here - Did you use the FB plans - and where are the pictures?

like the look of your arch

I am delighted at how that turned out and how easy it was to tie into the dome compared with the trouble a lot of others seem to have had. Next time I pass through kilkenny (which is once or twice a year) - I must call to have a look - you might be cooking by then
Aidan

[Amac]

Re: 39" Stargate Pompeii

Hi laku

Basically the idea is the same as you've done except that' I've used third cut similar to the ones you've done in the middle of your brick. That way you get two tapered bricks and a scrap,

Indeed - I was a bit surprised that the back and front of the brick took exactly the same taper (on the sides) which meant it could be done in a straight cut.
I had been shaving those tapers with the angle grinder, generating so much dust that my back garden is starting to resemble the sahara.
So it was a releif to just cut them directly. Of course I haven't measured anything - I just use the centre piece as a template - for the outside part of the brick, and the angle towards the centre has not changed since the first row so I use my old wooden template for that on top and bottom and then just join the lines on the inside.

I will change it to a more aggressive taper today

How is the weather in Finland - it seems a bit early for building or have you finished already?
Aidan
Aidan

[Laku]

Re: 39" Stargate Pompeii

How is the weather in Finland - it seems a bit early for building or have you finished already?

Mild at the moment with 70 cm of snow on the ground.

So no building for about two months still. My oven has been functional for over year. Housing is only partially finished, since I was too busy last summer to get it done.

It's weird feeling to cook with it when it's -20 c outside. Your upper body gets really warm and your toes are freezing.

[Cheesesteak]

Re: 39" Stargate Pompeii

Looking very nice -

If you want to get rid of that pile of rocks in your backyard - just put them on a pallet and ship them to me in California!

[Amac]

Re: 39" Stargate Pompeii

It's weird feeling to cook with it when it's -20 c outside. Your upper body gets really warm and your toes are freezing

Aren't finns used to extremes - like jumping from the sauna into the snow
- I researched it just now - and yes it is true

Q6 Do Finns really jump out naked into the snow in the middle of sauna bathing and roll around in winter time? Or go swimming in a frozen lake?
A6: Some do, most don't. This is a habit that requires a healthy heart and a bit of courage, but it is practised, and there are some enthusiasts who think sauna in the winter is nothing without a quick swim in the snow or freezing water. Of course, others think this is sheer madness.

But back to the bricks - I just realised that I should have been able to work out the correct angle front to back on paper in advance also. My mistake was thinking it should change as the rows went up because the circle gets smaller I've learned a lot in this build. Now I have to build another one

Finished row 6 - looks the same from the front so here is a different view. I can see why these domes crack - there is no room for expansion - in this row anyhow