Glenn's WFO

[glennb]

Re: Glenn's WFO

Just thought i'd add another quick update on my oven.
I checked the temp of the bottom of my support slab the other night after pizza's and it actually does warm up a bit. I could only test it by hand and it was warm to touch but certainly not hot, so guesstimate of 30-40 deg C.

I have a single layer of 50mm thick insulating board betweem my hearth bricks and the slab, and the concrete slab is 140mm thick, so to warm it up, there is a substantial amount of heating going into it.

It doesn't affect my pizza cooking ability as i can still get my oven floor bricks to 800F easily enough, but my oven probably isn't holding it's heat as long as others with better insulation under the bricks.

So, next time i build, i'll be either adding another layer of insulating board, or do a vermicrete layer under it as well (or both).

insulate.....insulate.....insulate....

[glennb]

Re: Glenn's WFO

Also a few notes on my oven performance:
Heatup takes 90-120 mins depending on how much wood i throw in.
Temperatures are good with 700F + in the floor and the air temp inside the dome at ~800F at cooking time. Does peak up to 1500F though when it's at full blast!

I let the coals die down and put my wood door on it at night, and the temps are at 200C the next morning and will typically drop to about 160C by that night (24 hrs).

Smoke out the front only occurs when i have the wind in the wrong direction, and if i use green/wet wood. Otherwise it draws pretty good.

I generally only cook 1 pizza at a time with the coals over to one side, but if I push it to the back, 2 12" pizza's are an easy fit in the front. The first pizza last weekend was done in the 90 second timeframe, but they take a bit longer as it cools a bit, but still 2-3 mins max.

[glennb]

Re: Glenn's WFO

wow, time flys.
I've been busy cooking and haven't posted a follow up on this, but I finally finished the render on the dome last weekend and cleaned up the arch brickwork so thought i'd post some photos.

Pizza's are going really well, although it's hard to find good Typo 00 flour here in Melbourne.
I'm loving the oven for slow cooking of one pot wonders (osso bucco, roasts, etc).
And I fail at bread making Well, there's room to improve at least.

I still need to render the bottom bricks, and paint the dome at some point, but not really in a rush at this point.

The dome render has a few cracks that open up when hot around the chimney, but this is purely due to the metal expansion and a good elastic type paint will fix it up.

[james]

Re: Glenn's WFO

When does it start feeling like autumn down there? We are definitely starting to look forward to spring up here.

Your heat up times will definitely come down -- you are seeing how important it is to keep feeding that fire and getting that high heat bouncing around. Next time your bread is starting to overproof before the oven is ready, you can stick it in the refrigerator.

James

[glennb]

Re: Glenn's WFO

Well, i haven't posted for awhile, mainly cause i've been busy cooking
I've had 4 pizza nights so far, and have also cooked a banana cake, pork roast, osso bucco, and a couple of attempts at bread. We have another pizza night tomorrow for some friends, so will be making dough again tonight.

The pizza's are improving, and i'm still experimenting a bit with flours (no caputo available in Aus, afaik). Cooking is nice and quick and they are coming out nicely done, so no problems with my oven temps. I do need to keep it hot though, by adding firewood to the coals as i'm cooking, as coals alone tend to let the air temp drop a bit inside.

The banana cake was fantastic and cooked really well, completely even both top and bottom. I actually think this cooked better than my normal fancy oven!.

My first attempt at bread failed as I overproofed it, but i was trying to cook bread during/after pizza, and my timing wasn't right. I will have to fire the oven for bread seperately to experiment some more.

The roast pork and osso bucco were fantastic, both cooked for about 3 hours at 150 C, which was the temp the day after pizza night.

My oven is taking about 1.5 to 2 hours to fully heat (floor bricks to 700F / 370C), but it's not weather proofed yet, so there is probably still a bit of moisture in the insulation. It doesn't take a lot of wood (using dry redgum), maybe 6 medium peices, plus a few to keep it going during cooking.

Once I close it up for the night at about ~300C, it is at about 200C the next day and drops about 50C over the next 8-12 hours, which is perfect for cooking/roasting. This is just using bricks to close the entrance, as I don't have a steel door yet.

Photos.

[glennb]

Re: Glenn's WFO

Beautiful job, Glenn. I really like the way it's looking. How did you fasten the chicken wire to the dome to affix the insulating blanket? Does the wire itself keep its shape? or did you secure it with wire towards the opening? I'll be doing mine probably next weekend.
Hope all continues to go well!

Carlos,
I used a couple (5) tapcon screws into the concrete slab around the dome. When i had the blanket on (it stays in place easily), i then wrapped my wire around and over the dome and just twisted a loop of wire from the bottom of the mesh, around the heads of the screws (they were hex head ones).

I should of taken a photo of that detail before i buried it

The rolls of mesh that i bought came with a bit of very thin straight wire, so I used this to tie from the edge of the wire mesh at the top to take it over the dome to the other side and tension it onto the tapcon screw.

After that, the wire just pushes into place, or can be twisted with a pair of pliers to take up any slack. The Vermicrete goes on fine without the wire though, so if you do your blanket going from the top of the dome down, then it may not be needed.

[exceloven]

Re: Glenn's WFO

Very nice Glenn. You'll be cooking in no time.

Mark

[carloswlkr]

Re: Glenn's WFO

Beautiful job, Glenn. I really like the way it's looking. How did you fasten the chicken wire to the dome to affix the insulating blanket? Does the wire itself keep its shape? or did you secure it with wire towards the opening? I'll be doing mine probably next weekend.
Hope all continues to go well!

[Salv B]

Re: Glenn's WFO

I'm concerned about the amount of moisture i'm putting back on the oven with the vermicrete as this stuff needs to be very wet to make it stick. I'll have to give it a bit of time before putting the final render on it, but i'm not worried about it cracking or anything, as the bricks will be completely dry by then.

Glenn,

Your build is looking great! It's great to get those curing fires finally going.
I know what you mean about the vermicrete. I did mine 3 weeks ago and it has been out there baking in the Adelaide heatwave and still some moisture came out after I fired the oven to pizza temperatures. I reckon it is worth doing a few full fires and cooks before putting the render on. If you are having problems with the vermicrete sticking I found mixing in a bit of fireclay into the mix helped a bit.

[glennb]

Re: Glenn's WFO

I agree with DB...Really great work. Anyone building an over now truly has a wealth of info and ideas to build a great WFO. IT kind of want to makes me want to build another.

This is a great testament to this forum and James, as I had no experience working with bricks at all before attempting this project. I knew a bit about concrete and i'm generally pretty hands on with tools and stuff but it was all new to me.

And I agree with you Bob about wanting to do it again (not for awhile though).

[glennb]

Re: Glenn's WFO

Very nice craftsmanship, Glenn! I wish I would have thought of that type of entry design....

Thanks DB! It's very kind of you to say so, but i'm my own worst critic so I look at it and think of all the ways I could do it better or improve things (next time maybe).

It was a royal pain the @$$ to do the entry that way, but i'm glad I did in the end.
Having to place small peices of wood on the fire, you need to reach in a fair way, and a smaller opening would just make it so much harder to do.

To be honest, when i look at the straight sided oven entry's, they don't look as structurally strong as a pure arch type, particularly if it's done with a single brick thickness. Doing my research, this was kinda proven by a few people who have had to brace their arch entry sides. So I sat there for about a week thinking about how I could do it better (that's the Engineer in me talking), and then proceed slowly to build it up.

Once the chimney heats up a bit, the draw is actually pretty good, and i only get a bit of smoke out the front during wind gusts.

The other interesting (funny) thing about my build, is that although I initially had the oven drawn up in AutoCAD and all these fancy plans, once i started building, I just kinda went with the flow. I didn't use any bracing inside the oven at all (thanks to the sticky premix mortar). I used a arch form for the inner arch, but the entry and vent area was built using the patented "one eyed squint" method for working out my cuts and angles.

[glennb]

Re: Glenn's WFO

Hi guys and thanks for the positive comments.
The curing fires are going great and had my 3rd one last night, with no cracks and no detectable moisture coming from the oven.

The dome's been built for at least a month now, and there is hardly a drop of moisture in the whole state, let alone my oven, but even so, i'm taking it easy with the flammage.

I've got the thermal blanket on it now and just started putting the vermicrete layer on it as well, but I only have 2 bags of Verm, which isn't going to go very far (photo shows result of pretty much one bag only).

I'm concerned about the amount of moisture i'm putting back on the oven with the vermicrete as this stuff needs to be very wet to make it stick. I'll have to give it a bit of time before putting the final render on it, but i'm not worried about it cracking or anything, as the bricks will be completely dry by then.

I've finished the brickwork around the outside and i'm happy with how it will turn out once the dome is rendered. The pavers are angled away from the dome a bit to make sure the rain runs away from it in winter.

[Bob C]

Re: Glenn's WFO

I agree with DB...Really great work. Anyone building an over now truly has a wealth of info and ideas to build a great WFO. IT kind of want to makes me want to build another.

[dbhansen]

Re: Glenn's WFO

Very nice craftsmanship, Glenn! I wish I would have thought of that type of entry design....

[carloswlkr]

Re: Glenn's WFO

How are the curing fires coming? How's the oven taking it?