100 cm oven build, Sweden

[ugnsnisse]

Re: 100 cm oven build, Sweden

Finally! I lost momentum for a while, especially since the mosquitos and sandflies made their entrance.

Since I've had no feedback on the buttressing I went without. To minimize the load the flue will be welded to a fitted metal sheet and fastened somehow to the arch with no more bricks.

All in all I'm really happy with the entry, the bricks have been cut on the visible side to make a nice clean impression.

[ugnsnisse]

Re: 100 cm oven build, Sweden

Lit an imaginary fire yesterday, chipped of the wedges with a chisel and filled back the stone wall.

The oven floor is situated 140 cm above ground, and that is too high even for tall handsome men like me.

The plan all along has been to build a deck in front of the oven, until that is done I will fit a metal platform of 150x150cm directly on the massive rock that I unearthed below.

I'm thinking 110 cm from platform to oven floor, any other suggestions?

[Greenman]

Re: 100 cm oven build, Sweden

What is comfortable to lean on is a starting point. There are more considerations like the view of the fire for the guests and things like that. It comes down to personal preferences and not cooking 50 pizza at a session means that the physical operation of the oven is less important than the other things for me.

[ugnsnisse]

Re: 100 cm oven build, Sweden

Made some oven tools today. The wide one is really heavy but as greenman says it won't be used for hundreds of pizzas at a time.
Have found some wooden handles of 180 cm length that I'm considering using.

Also set a newspaper on fire in the oven. Had some smoke escaping out the front and that makes me think that I could've made the chimney-opening a pair of bricks wider.

My thoughts on the 7 day curing process are as follow: what's the purpose of it?

If it's for drying out the brick and mortar, wouldn't it be better with a continous source of heat, for example some tea candles?

Just one blazing fire for 20 mins every 24h seems to do little good, theoretically.

[Gulf]

Re: 100 cm oven build, Sweden

My thoughts on the 7 day curing process are as follow: what's the purpose of it?

If it's for drying out the brick and mortar, wouldn't it be better with a continous source of heat, for example some tea candles?

Just one blazing fire for 20 mins every 24h seems to do little good, theoretically.

More bad than good imo. The fires are meant to be started small, adding fuel slowly to get your oven up to temp, and holding that temp for as long as you have time for, that day. And that means resisting the urge to go overboard with it! I personally like the charcoal (heatbead) method introduced by one of the pioneers on this site, Karangi Dude, (for the first fires). Tea candles might make a great pic, but would be like pssing into the wind, as for as drying the oven goes

Edit: Also, preheat the flu/chimney before starting a fire in the oven, and see how that works out for you .

[ugnsnisse]

Re: 100 cm oven build, Sweden

After reading 5 or 6 pages in the curing thread I came upon the new (newest?) recommendations that seems to make more sense, longer fires that is.

I got the flue today and sanded it with a 120 grain paper to a matte finish. The pipe plus the sheets that I will weld it to weighs in at 15 kg. I have no idea if that is a lot of strain for the arch or not.

The metal sheet with the hole in it is in fact two layers of 1 mm sheets that will be spot welded together, with the intention to get a product that resists warping better than a single layer.

I light a fire in the morning then keep a continous fire in the afternoon/evening. Have had the back wall of the dome up at ~170 C. It's raining here so the curing is taking place under a tarp.

[ugnsnisse]

Re: 100 cm oven build, Sweden

More curing going on today. The dome has catched a leathery tan and is reaching the mid 200 C.
There are some hairline cracks on the outside but nothing can be seen inside.

[UtahBeehiver]

Re: 100 cm oven build, Sweden

Really be patient with the cure. Slow is good. I know it is exciting to see fire but don't go too fast and hot too quickly. Hate to see all this work get ruined.

[ugnsnisse]

Re: 100 cm oven build, Sweden

I'm trying to stick to the schedule and hope for the best.

I'm considering putting in a vent in the render, maybe a 60 mm circular net of sorts.

Top or bottom placement?

[ugnsnisse]

Re: 100 cm oven build, Sweden

Decided to go with buttressing the outer arch. The angle irons were welded on spot to get the right support.

[ugnsnisse]

Re: 100 cm oven build, Sweden

Tried a pizza tonight, it went well. The first one at least.

The second one clinged on to the peel and got banana shaped but also very tasty.

The vibrating interior of the dome and the acoustics of the fire is a fantastic experience.

Play with fire AND make pizza!

[ugnsnisse]

Re: 100 cm oven build, Sweden

The oven keeps on churning out pizzas. A crack has appeared in the back interior, maybe 1 mm wide and 40 cm long. Is it possible to smear some mortarslurry in there when the dome is cold or should I just let it be?

The S/S-tools feels rough on the oven floor. I've changed from steel to aluminium on the peel, the turner is still steel.

[ugnsnisse]

Re: 100 cm oven build, Sweden

Someone wrote that a rendered finish on the dome is the easiest way to go. That person must either be crazy or seriously deranged. Or is it just me using the wrong stuff.

What I'm talking about in perticular is layer nr 2, making it stick to nr 1.

I just can't seem to make layer #1 wet enough that layer #2 will smoothly attach by force of whatevermakesitwork.

The technique that I developed consisted of using my hands to smear the stuff on to the first layer and by doing this I actually made some progress. Will give it another try tomorrow or some other day.

As you can see in the pictures there's no vermicrete in this oven. Wasn't any room for it really.
Got given some ceramic blanket that just about was enough for the dome, then I used some rockwool and finished of the whole thing with a layer of nasty old fiberglass blanket with chicken net already attached.

Got a cracked floorstone and one crack in the inner arch. Still standing.

[Gulf]

Re: 100 cm oven build, Sweden

This is what I did, though I applied mine over vcrete. But, it should be the same:

Get some some acrylic concrete fortifier. It is also a good bonding agent. Paint it on with a brush, and go to work before it dries.


I used a 12" short handle sheetrock seam trowel.



It has a slight curve built in to it. It will take a little pratice to figure how much stucco to load on to the trowel. Forget the handle, grab it by the ends. Start at the bottom and apply in a vertical motion. It will apply about 3/8" to 1/4 " for about 16 to 18 inches verticaly. Go all the way around the dome overlapping the runs about a couple of inches. Now go back to where you started. If it has dried out, you will need to apply some more fortifier by brush. Overlap the bottom run by about 4". Each horizontal run gets shorter (and faster) as you go up the dome towards the apex.

If after completing one complete layer you decide to stop for lunch, or the day: (before doing so) Take a course sponge and wet it in a bucket. Wring it out and start at the bottom in the driest areas. Wet a small area with the sponge. Use circular motions to knock down the high spots and fill up the low spots. Rewet the spong and repeat until you have covered the entire dome.

Before applying another layer, apply another coat of fortifier.
It takes 3 to 4 applications to get 3/4 to 1" of stucco on the dome. But each coat is much quicker than the one before.

This method will add and lock in water to your oven's insulation. I very much advise installing a vent at the apex of your dome. At least temporarily.

I hope this helps .

Edit: This technique can be applied to your entry as well. You just have to orient the trowel to the curve of your entry arch.

[ugnsnisse]

Re: 100 cm oven build, Sweden

Ok I will try that approach. Though I thought that it was good to leave the surface as rough as possible for the next layer.