Oven on wheels

[wotavidone]

Re: Oven on wheels

Set backs, setbacks.

Advice required, please.

1) Turns out my flue is only 5". I dunno how I missed it. I've built a smallish oven, and that works out to 15% of the area of my opening. Enough?
The smaller Forno Bravos, from which I drew much inspiration for diameter, height and opening size, have 5 inch I.D. flues.
2) The missus "suggests" a brick arch would look better than a stainless hood. If I build a one brick deep arch butted up against my current arch, which is a half brick deep, the entire depth of my vent/arch area will end up nearly 14 inches deep. Anyone think one and half bricks deep is too far to reach to get to the oven proper?
Regards,
Mick

[david s]

Re: Oven on wheels

I think a 5" flue is probably too small for your sized oven. Mine has a 5" flue, but it is only 21" in diam. You could increase the draw by doubling the height of the flue. Another section should fit into the top flange.

[cobblerdave]

Re: Oven on wheels

Gudday Mick
The chimney sizes had me as well.... my budget was pretty much expended by then and an 8 in stainless was out of reach. Just took the brickwork up keeping it wide... 3 1/2 bricks... and high enough over my head to take the smoke away and it worked and no smoke stains on the front as well.
1 1/2 bricks should be a problem for the entrance mines 2 bricks deep (500mm/20 in) but is wide 600mm/24. I often lite a fire in the entrance area and use a a fireplace and don't notice a problem operating the oven in fact its an advantage to have a rest area in front for pots and pans

Regards Dave

[wotavidone]

Re: Oven on wheels

I received a call from a mate yesterday, who just sold his house and is busy clearing out his sheds. He said years ago my old man bought some stuff from him and never picked it up, and he's just found it. Did I want to come collect it? So around I went and picked up a big bag of cast aluminium corner brackets for making frames from square tube. The sort that just push into the ends of the tube. Wish I'd known about them when I started framing my oven enclosure. Anyway, he had a trailer load of metal destined for the scrap pile. Including a brand new section of 6 inch stainless steel flue pipe. Problem solved!
And another mate, who was around giving him a hand said "Do you need a nice new rain cap? I'm sure I've got one, and I'm moving house soon too, I'll see if I can dig it out."

[wotavidone]

Re: Oven on wheels

S I've got the enclosure built around my oven. Yesterday I mixed 6:1 vermiculite and cement. I poured it in around the oven. I didn't do any tamping, not wanting to compromise the insulation value.
This morning it hasn't bonded the pieces of vermiculite together at all. Not one bit. I may as well have poured it in loose. Have I done it wrong, or is it just too early to be checking it?
I hope someone is on-line who can advise, as I'm down to my last bit of vermiculite. If the advice is to pull it out, at this stage I reckon I could almost resue it.

[david s]

Re: Oven on wheels

Mick,
If you have an enclosure then there is no need to add water and cement, however as you've already done it it's too late. adding cement, particularly a rich 6:1 reduces the insulation drastically. For a 6:1 brew you will have added more than double the mass of vermiculite, which increases the density and thereby reducing insulation value. You may have added too much water which tends to wash the cement off the grains of vermiculite to the bottom of the mixing container leaving you with some of the stuff not properly coated with cement. I've found the correct amount of water is 3 L /10 L vermiculite, but this does depend on the grade used (fine needs more water) I think you probably should have tamped it down a bit. Never mind, the vermicrete should still be held in by your enclosure so it shouldn't matter if some of it is loose. I find the stuff usually goes firm in 24 Hrs.
Hope this helps.
Dave

[wotavidone]

Re: Oven on wheels

Thanks Dave
being an impatient bugger I went out and dug the stuff out. I mixed a new lot, and I believe the problem is the amount of water I used. I used nowhere near the three litres per 10L of vermiculite you suggest. I made the next lot much wetter, and presto now the very coarse vermiculite granules are properly coated with cement paste. I reckon this lot will work well, I tamped it a bit this time, as per your suggestion. The very coarse particles have a lot of air spaces between them despite the 6:1 ratio, so I reckon it'll all be good. Better than no insulation, anyway. I'll find out, I guess.
Can't wait to fire it up and measure the temperture of the outside corrugated iron skin of the enclosure.
Thanks for getting back so quickly.

[david s]

Re: Oven on wheels

Mick,
If you've used a couple of bags of vermiculite then you will have added about 60 L of water. Because you have an enclosure then there is no danger of cracking your outer igloo shell, but it will take many fires to drive off the 60L. Have you left off the roof so the moisture can escape to the atmosphere? Moisture will tend to condense against the inside face of your steel sides so expect the drying process to be slow. You will find that the outside will probably be warm to the touch while the vermicrete is still moist but when it is dry the outside should be cool even after a few hours of fire. You will also notice that the oven performance improves as it becomes dryer.
Good Luck, you're almost there, throw in a chook, you won't be disappointed.

Cheers,
Dave

[wotavidone]

Re: Oven on wheels

Hi Dave.
Currently, the roofing iron is on, held down with what my mate who is married to a Filipina calls "Philipines Roofing Nails", i.e loose bricks. This is because right now its bucketing down rain.
Soon as I can get some dry weather, I'll be taking it off to get the vermicrete dry and fit my stainless steel flue.
Nearly there, hopefully I'll be lightiong a decent fire in it soon. I've had it fairly hot before I put the insulation on, and I'm pleased to report I only have a few very hairline cracks. I'm starting to feel confident nothing will fall down.

[cobblerdave]

Re: Oven on wheels

Gudday
Things never come easy to you Mick....congrats on the progress....perhaps some pics are in in order oaround now

Regards Dave

[wotavidone]

Re: Oven on wheels

Gudday
Things never come easy to you Mick....congrats on the progress....perhaps some pics are in in order oaround now

Regards Dave

Things aren't coming that hard either, Dave The rain is actually very welcome, my tank is full again, and the thing with the vermiculite was no big deal. Would help if I didn't change my mind all the time. I blame all the thinking I do at work. My hobby projects aren't supposed to require any thought at all.
Still, it hasn't tested my brain as much as my last project. See attached photo of last project celebrating Christmas with the wife's nephews.
I'm "stuck" in a flash hotel in Adelaide at the moment, some times work is so tuff. I'll post some photos later in the week.
Its all about experience. The next one would get every step done right first time, and only take half a dozen weekends.
I was talking to a guy today who has an 8 inch thick concrete slab to build his oven upon, and is not intending to insulate. I shall have to see if I can influence him to at least insulate underneath the floor.

[cobblerdave]

Re: Oven on wheels

Gudday Mick
Sorry for the late reply. We are the same up here, full tank and wettest winter for 12 yrs and this is suppost to be the dryest season! Unfortunatly wet oven/ wet wood as well so no pizza or weekend roasting for a while. So know how you feel with lack of progress.
Working on some overhead cover ideas... have the frame from a round trampoline and hope to use it to form a round cover over the WFO... hate the idea of plain square timber structure. Still in the planning stage though.

Regards Dave

[cobblerdave]

Re: Oven on wheels

Gudday Mick
Hows it going? of course I read the bambo post...so your up to drying the oven out? A coupla pics would be nice to see your progress

Regards Dave

[wotavidone]

Re: Oven on wheels

G'day Dave.
Sorry I've been a bit tangled up with work. I generally get Sunday arvos to work on it.
Here is my "tin shed oven". Can't see any major cracks. Yesterday and today I got into it and its finished, near enough.
Fired it up with bamboo and got the dome clear in less than one hour, swapped to hardwood and cooked my first pizza.
Roast veggies for tea tonight with the left over heat.
Still making condensation as it fires though, so I reckon it'll get better.
Stainless steel hood performed allright yesterday, but it was windy today, and I ended up stacking loose bricks to keep the drafts from blowing ash over the floor and smoke out the front. I may have to lay them permanently, I think.

[cobblerdave]

Re: Oven on wheels

Gudday Mick
Good to see your pumping out food from your oven....makes the journey worthwhile. Your journeys bin a bit hard for oven parts so I think that firstpizza would have been real good.
CONGRATS!!!

Regards Dave