Experimental Norse-Kiwi Hybrid Oven!

[cobblerdave]

Re: Experimental Norse-Kiwi Hybrid Oven!

G'day wildflower
Here's a link to Anne's oven showing her formwork

http://www.fornobravo.com/forum/6/ru...tml#post151558

Yours will need to be a little different as Annie pulled hers out through front of her oven and you can't. The end form piece will have to have hole in it so that you can access the inside of the oven. You'll need that as you can then lite a fire and burn the form out, so you had better build it out of something other than a cupboard end like Annie

Regards dave

[Wildflower]

Re: Experimental Norse-Kiwi Hybrid Oven!

Hi Dave,
Good to hear from you!
I would like the arch to extend over the row of the back wall...question for you...do you build the back wall up first, and hope that you've got the right shape, or do you build the arch first, then cut and fit the bricks in to fit under the curve of the arch?
Cheers,
Zoe.
PS Thanks for the tip about the burnable formwork!

[cobblerdave]

Re: Experimental Norse-Kiwi Hybrid Oven!

G'day
The end walls should be built first then the arches built on top of them . Then as you get expansion and contraction the arches can drop back and bear down on the end wall . Build the end wall separate it might just drop off.
As for the brick cuts you might have to use an angle grinder with a masonry or better diamond blade to par the brick down into the shape you'll want. Can't cut curves but a curve can be created from a lot of small start cuts.
Regards Dave

[Wildflower]

Re: Experimental Norse-Kiwi Hybrid Oven!

Hi Dave, as per your tip, I've built the back wall first...hopefully it will fit nicely under the planned arch. I was lucky enough to have a local bricklayer help me out by cutting the bricks for me. Finished laying the back wall and the starts for the arches today...getting the hang of this a bit now!
My design for the arches entails using very little mortar where the bricks join inside, so I was thinking about putting them into place on the form, then chocking them apart so they're steady, and then squidging the mortar down from the top while they're they're in the right position. After the formwork comes out (burns down!) I could go perhaps get inside the oven (could I fit?) and finish off the mortaring from the inside if it's needed...is this a cunning plan, or should I just butter the bricks as I go and place them on the arch from one side to the other?
Thanks again for your sage advice, it is awesome!
Wildflower.

[cobblerdave]

Re: Experimental Norse-Kiwi Hybrid Oven!

G'day wildflower,
Recon you've done awesome! You have done Annie proud, the "local bricklayer down the road" fits into local ingredients I'm sure .
I recon your plan of minimal cement on the faces then spacing the outer bricks with chocks then doing the pouring mortar in the spaces will work . In fact the Italians use the same method!
The front arch? The bit that connects to to the stove "front". What's your plan?
Regards dave

[Wildflower]

Re: Experimental Norse-Kiwi Hybrid Oven!

Hey Dave,
Well, that's nice to hear about doing Annie proud...she was a real source of inspiration that's for sure, so that's very heartening.
I will try the proposed "Italian" method for the first arch, and I guess if it's doesn't work that well, I can always change for the second arch.
I was going to use firebricks and angle iron at the front of the oven to form the "doorway", and have some bricks placed along the top and sides to link the first arch to that...will see how it looks once the arches are in place! I see from reading the forum that this area often poses the most problems for WFO builders...yikes.
I have to see if I can sort out a damper for the chimney flu too...
Totally enjoying this challenge, and looking forward to pizzas and slow-oven-cooked meals fed by driftwood off the beach.
Thanks again,
Zoe.

[cobblerdave]

Re: Experimental Norse-Kiwi Hybrid Oven!

G'day wildflower
Sounds like your going to do a series of single arches ,not the best method. Your better to build them overlapping like the bond of a brick wall. It's that much stronger and you have to build in strength when building an oven that gets to 500C plus . Notice your domestic one only goes to 240 max.
As ever parent knows when a child builds a Leggo house in single units and you tread on it with bare feet it breaks. But they discover the overlapping method and you tread on their structure with bare feet... That is going to hurt. The strength difference is like that.
I'd use Annie's method of spanning the arch ends with the tomatoe stakes ( not treated ones!)
You'll have to have 1/2 bricks and its a simple as getting a brick bulster from your bricky friend. With a hammer tap on a soft surface like the ground they will snap in 1/2... Easy. Not perfect ... Don't worry you'll only need them on the ends and they will never be seen.
Regards Dave
PS you'll need chocks, little spaces for the Italian method , purpose cut wood would be great but at a pinch a waxed cardboard fruit box cut into lengths then folding in 1/2 works. You just push them in till they hold the correct angle.

[Wildflower]

Re: Experimental Norse-Kiwi Hybrid Oven!

Hey Dave,
I was wondering if you were going to call me on my non-staggered weak arch design! Trouble is, I am using tapered bricks for some of it, and don't have enough to do that offset...I think..will double-check.
It's such a small oven, there will be only two arches. I am also going to reinforce the sidewalls and back walls by putting up ceramic fibre board back by iron grilles (yes, scavenged from the dump!). You might see the re-bar and posts I've put into the base for this purpose...such is my lack of faith in my own bricklaying ability!
Still, I'll go back to the drawing board and see if I can work out a staggered pattern with the bricks I have.
I have used my bolster and hammer to sever two bricks in half so far (in the walls), and was amazed at how easily they broke in two.
Thanks again,
Zoe.
HAHA, yes, we all know the pain of standing on Lego with bare feet in the middle of the night!

[cobblerdave]

Re: Experimental Norse-Kiwi Hybrid Oven!

G'day wildflower
Ultimately you are the builder ! You call the shots !
Me I'm here to help as much as I can. I'll feed you as much information as I'm able.
I'm sure you're WFO will work for you. Your a thinker you will make this thing work, I'm sure .
Regards dave

[Wildflower]

Re: Experimental Norse-Kiwi Hybrid Oven!

I decided to take on the challenge, and made my vault with the offset brick pattern. One or two of the wedge-shaped bricks split along a different plane than expected - I guess because they're second-hand and very old they had existing weaknesses....anyway, it didn't really matter. I did a "dry-run" over the form I built, and I was actually pretty pleased with how they looked!
The form is made of 3 custom-wood arches with an old real estate sign screwed onto the top, and some spacers in between the three. I have about 40mm gap at the front between the start of the vault and the stove, so my plan is to be able to slide the forms out and cut the top out in 40 mm strips (a bit of a pain, but I'm not too keen to have a raging great first curing fire by burning out the form work..yes, Dave, I've read about your exciting build!).
I had a bit of time today and managed to do a few rows, and it was great fun. I'm using wedges of the real estate sign between the bricks to make sure they are sitting in the right position. I decided to butter the bricks like normal, not force the mortar in once in position - so far, so good!
Also got some angle-iron from the wreckers cut so that it will fit inside the stove to support the chimney bricks...is it ok to use galvanised iron? It turns out that's what I got from the wreckers.

Best wishes and thanks for the encouragement!
Zoe.

[cobblerdave]

Re: Experimental Norse-Kiwi Hybrid Oven!

G'day wildflower
Now that's looking really good. I'm impressed with what you have achieved. I don't know wheather that signs really what the company thought they would be used for but what tha... They certainly get extra advertising exposure.
Love the cut bricks they set up the arch angles perfectly!
One thing that might be a problem is that galvanized iron. Zinc melts at. 300 C. Welders hate it as the fumes from the welding can make you sick.
I myself would not use it.
Sorry .... But I'm blunt as that . Its a heavy metal like lead.
Can not wait for more pics
Regards dave

[Greenman]

Re: Experimental Norse-Kiwi Hybrid Oven!

Hello Wildfire - Your build is inspirational and in the true spirit of those of us who believe in re purposing to get the job done on a budget. It is looking good.

I would share Dave's observation about the fumes from the galvanised steel. Someone more educated in physics will be able to provide quality information about the effects of heat and galvanised steel and how long the effect may persist.

I like your style. Good luck with your build.

[Wildflower]

Re: Experimental Norse-Kiwi Hybrid Oven!

Crikey! I had a bad feeling about that galvanised iron, and of course, now I know the zinc fumes are poisonous, well...it won't be going in my oven!
I might see if I can rustle up enough off-cuts to do an inner arch and forgo the iron altogether.

[cobblerdave]

Re: Experimental Norse-Kiwi Hybrid Oven!

G'day wildflower
A good supply of non zinc coated angle iron is old bed bases. You might want to check out the secound hand stores?Friends? Throw outs?
I've still got a couple of lengths in the shed from that source that I recon could come in handy one day
Regards Dave

[Wildflower]

Re: Experimental Norse-Kiwi Hybrid Oven!

Hey Dave, that's a great idea - but doesn't it matter also if there is paint on the angle iron? I've got other bits of angle iron around, but they all seem to be painted or galvanised. Perhaps I should just try and go for bricks and mortar.
I'm starting to wonder how on earth I'm going to join all this up with the chimney flu which is going to be floating up above the inner arch since I'm using the jotul stove. I will need to somehow funnel the smoke up to the chimney, or else it won't draw as well - right?
Anyway, I got the vault done today! No major dramas, really, except I suppose one of the "keystone" bricks was too fat - and I couldn't push one end all the way down to the form, so there's a lump in the top of the arch, and I guess a corresponding divvet in the ceiling of the vault below - but oh well, that's fine by me.
Looking forward to firing the first curing fire!!!