Finally decided on 32in castable dome

[david s]

The soot should burn away at around 300C (572F) By the sound of it you still haven’t got the oven hot enough yet. Sometimes a wet oven wil display a persistent ring of black around the base of the dome. This is an indication that it is still damp in that place, so the fire still needs to be fairly gentle. I catered for a wedding last night and I fired my oven for longer than usual because there were wedding delays. After 3 hrs the top of the dome registered 650C although this is only the surface temperature (IR temperature guns are not really that useful).
Regarding the wire brush, do not use it. There have been incidents of people ingesting bits of wire with can lead to very serious consequences. A length of 1/2” pipe is far better, just blow, don’t suck.

[Mullster]

Ready for my first pizza tomorrow!

So I think (never sure) the curing has gone well. A week of increasing fires - saw 700F on the dome tonight. There doesn’t seem to be any sign of damage or cracks, no suspicious smells other than smoke.

I have lots to learn about fire and oven management and I know most of that will come with practice and getting to know my oven but I do have a few questions hoping you guys can help with:

• what does clearing of the dome look like? I get the sense the soot disappears at a certain heat? So far it’s pretty black in there!
• Tomorrow when it’s pizza time do I simply move the fire (I’ve been practising) and then wire brush the hearth to move as much dust/ash as possible?

Can’t believe it’s almost pizza time!

[Mullster]

All awesome advice - much appreciated! As suspected my expectations are probably a bit high for how much the oven can ‘do’ yet. Tonight’s will be smaller logs and briquettes too

[david s]

It's important to try to keep flame impingement on the dome to a minimum during the first few days. That is why using briquettes in conjunction with a little wood to keep them alight works pretty well.
This is the advice I provide for my ovens. Bear in mind my oven is only 21" diameter so some adjustments would be required re size.


Use the seven fires in seven days method.
This process is important
Start with a very small fire in the centre of the oven, using small sticks only. If this first fire has flames touching the top of the oven for too long, then the fire is too big. Repeat this the next day, making the fire a little bigger and of course it will burn for a little longer. Repeat this procedure for seven fires getting progressively bigger and longer.

Heat beads are a good way of getting gentle heat into the oven, so as well as the wood, add one handful on Day1, 2 on Day2, 3on Day3 etc.

(You will probably notice dampness of the insulation layer as you heat the oven. This is normal and indicates that the oven is drying itself out. These damp patches will feel hotter to touch. This is a good indication of how the heat can pass more easily through wet material. Your oven will be far more efficient once it is properly dry. Some 50 litres of water has gone into the construction of the oven and considerable fuel is required to convert it to water vapour .Be careful- don’t be tempted to build up the fire too much, but try to keep those coals burning as long as possible- all night if you can)

This process is a bit laborious and goes through quite a lot of fuel. However, once properly dry you will be amazed at how little fuel your oven will use- around 4-5 Kg to get to temp. and that energy will be captured for hours of useful cooking time.
By all means use the heat you’ve generated to do some cooking. Maybe a loaf or two of bread, a roast, marshmallows or pastries etc. But don’t attempt to get up to pizza temperature yet. (You can test if moisture is still present by placing some plastic on the outside and seeing if moisture is collecting there.)

Driving off the moisture

Day 1: 1 sheet newspaper and half a dozen small sticks, 1 h’ful of heat beads (about 5 mins of flame)

Day 2: 1 sheet of newspaper and about 10 thicker sticks, 2 h’fuls of heat beads (about 10 mins of flame)

Day 3: Bigger sticks, plus 3 h’fuls of h’beads (about 15 mins of flame)

Day 4: More wood, plus 4 h’fuls of heat beads (30 mins of flame)

Day 5: wood plus 5 hfuls of h’beads (45 mins of flame)

Day 6: wood plus 6 hfuls of h’beads (1 hr of flame)

Day 7: wood plus 7 h’fuls of h’beads (1 ½ hrs of flame)

[deejayoh]

Hugh is right that Chestnut is probably not the best choice for cooking, but it doesn't really matter what wood you use for curing - as low and slow fires are best. I think I used a mix of framing timber and other softwood lumber...

Your issue might just be that the dome is still fairly wet. Doesn't look like you've gotten the dome very hot as there is still newsprint on there. You might just want to use some briquettes/aka heat beads to get it up to a reasonable temp for a long period of time.

[hughjamton]

I’m not sure to be honest - it’s from a local farm shop who in turn get it from a local wood - I’ll ask next time - if it was chestnut would that be a problem?

It wouldn't help, it doesn't produce much heat when compared to other timbers and doesn't burn well, if I use it in my log burner I put a different wood in with it to keep it burning. It also spits a lot so not recommended for open fires.
Although I believe that all ovens are a pain to keep the fire going until they dry out properly regardless of the wood used.
Are you getting a strong concrete smell during the firing?

[Mullster]

Is that chestnut wood?

I’m not sure to be honest - it’s from a local farm shop who in turn get it from a local wood - I’ll ask next time - if it was chestnut would that be a problem?

[hughjamton]

More curing fires - I think my fire-building needs work!

So the top of the dome hit 500F momentarily during tonight’s fire but I’m not convinced about how I’m building the fire - I’m not sure the logs are burning as long as they should and at this rate I’m going to need quite a lot of them to hit a 700F fire.

A few questions:

1. Clearing the ash from previous fire - should I salvage any solid pieces (see pic)?
2. Do you think the logs I am using are too big?
3. Im using kindling and firelighters at the top which is getting it started well but maintaining seems to be the challenge - any tips based on the pics?

Cheers guys

Is that chestnut wood?

[Mullster]

More curing fires - I think my fire-building needs work!

So the top of the dome hit 500F momentarily during tonight’s fire but I’m not convinced about how I’m building the fire - I’m not sure the logs are burning as long as they should and at this rate I’m going to need quite a lot of them to hit a 700F fire.

A few questions:

1. Clearing the ash from previous fire - should I salvage any solid pieces (see pic)?
2. Do you think the logs I am using are too big?
3. Im using kindling and firelighters at the top which is getting it started well but maintaining seems to be the challenge - any tips based on the pics?

Cheers guys

[Mullster]

Brilliant, cheers, just to check, was it 1:2:3 mix of cement:sand:gravel? Just reading different things and kinda hard to see what would work. I've got some glass to put in to try and polish up. I'm on amazon as we speak for polishing discs lol. Budget is blown so what the hell

Cheers

Yep a 1:2:3 mix - I think the dye was an extra - I probably used a bit more water to balance things out. Looking forward to seeing your arch/front!

[Daveholdn]

Thanks Daveholdn I like it too - hoping I can get it to shine some more with some sort of varnish. I just did a standard concrete mix (all one mix) in the end made with pea gravel - you might be able to find some more detail earlier in the thread. I bought a 1kg cement dye to try and get it black and even though jet black was the aim I’m not sure how possible that is - I used the whole tub and the arch is not that big!

For polishing I watched a couple of YouTube clips and then invested in some polishing discs for my angle grinder. I think they were about £20 off Amazon for a set of 15. You start at something like 20 grit and work your way through the discs up to something like 3000 grit.

To be honest it was hard work. The vibration on the grinder was unreal - if I had my time again I would spread the effort over a few hours and do an even more thorough job - I was too keen to get it done and see the final shine! I probably could have spent a bit longer on it.

Brilliant, cheers, just to check, was it 1:2:3 mix of cement:sand:gravel? Just reading different things and kinda hard to see what would work. I've got some glass to put in to try and polish up. I'm on amazon as we speak for polishing discs lol. Budget is blown so what the hell

Cheers

[Mullster]

Looking really good Mullster , I'm about to cast the front decorative arch. Can I ask what mix you used and did you cast in two different mixes? Also just waiting on my coloured glass but how did you polish up your front arch? Looks class.

Cheers.

Thanks Daveholdn I like it too - hoping I can get it to shine some more with some sort of varnish. I just did a standard concrete mix (all one mix) in the end made with pea gravel - you might be able to find some more detail earlier in the thread. I bought a 1kg cement dye to try and get it black and even though jet black was the aim I’m not sure how possible that is - I used the whole tub and the arch is not that big!

For polishing I watched a couple of YouTube clips and then invested in some polishing discs for my angle grinder. I think they were about £20 off Amazon for a set of 15. You start at something like 20 grit and work your way through the discs up to something like 3000 grit.

To be honest it was hard work. The vibration on the grinder was unreal - if I had my time again I would spread the effort over a few hours and do an even more thorough job - I was too keen to get it done and see the final shine! I probably could have spent a bit longer on it.

[Daveholdn]

Looking really good Mullster , I'm about to cast the front decorative arch. Can I ask what mix you used and did you cast in two different mixes? Also just waiting on my coloured glass but how did you polish up your front arch? Looks class.

Cheers.

[Mullster]

Aiming for 400F

So it was my 3rd curing fire today. I bought myself some wooden fire lighters - made it so much easier to the get the fire going. Also tried the top-down approach - logs on the bottom, kindling next and then the fire lighters on top. Worked well and the fire got going pretty good.

I only managed to max out at 300F rather than hitting 400F today. I’m not too worried - all the advice is to take it slow rather than push it so I’ll go again tomorrow and see if I can nudge it up.

To be honest I think I have quite a bit to learn about how to effectively build a fire - configuring the fuel and stuff so perhaps that’s what held it back today. Perhaps the oven still has a lot of moisture and that’s holding it back?

I don’t mind too much - I’ll only worry if a few days from now I’m still not getting above 4-500F!

On another note I took the plunge today and starting building the glazed pergola the oven is going to sit under! Had to create a hole in the existing decking so there is no way back now - feels a bit like when I ripped the flagstones up 4 months ago and went all in on the oven!

[Daveholdn]

First curing fire!

Its here! I finally arrived at the point of the first fire! Following the 7 day guide I loaded a few balls of newspaper into the oven and set my first fire. The paper lit easily (no surprise) and it burned well. I used a full newspaper in the end for a fire of about 10 mins.

Ive bought a laser thermometer so had fun checking the temperature at various points of the oven. Saw the dome hit 200F towards the top of the oven so even though it was brief I thought I’d play it safe and leave it at that for tonight. Kindling fire tomorrow.

The flue seemed to work, drawing the smoke up - there’s no soot on the oven front - which feels like a good sign to start with.

I want to reiterate a massive thanks to all of you who have got me this far and encouraged me along the way.

I know I’m not home and dry yet - more still to do before I can taste pizza over and over again.

Looks class, great job mate.