Casting Homebrew Oven - Build Log

[Mullster]

10m x 10m - I thought mine was big at 6x3!! (Size isn’t everything ).

I have progressed the glazed pergola - got 1 beam set and 2 of the 3 posts for the other side ready - hoping I can have some glazing in place a few weeks now.

Can take the finishing touches to the oven at a slower pace then.

[aaronpizza]

So my dome is built and insulated (photos to follow).

I am going to tile it however it is not covered up 100%

How can I ensure it is waterproof? Or is tiling/grout enough to achieve this?

would love advise one this one please

[aaronpizza]

So my dome is built and insulated (photos to follow).

I am going to tile it however it is not covered up 100%

How can I ensure it is waterproof? Or is tiling/grout enough to achieve this?

would love advise one this one please

However, I'm also thinking a waterproof render will be A LOT easier and cheaper to do...

[sergetania]

aaronpizza I have just finished a stucco layer and after it dries for a while I am planning to use an elastomeric flashing sealant to waterproof the dome (I saw David S recommending it somewhere).

It is not cheap but if it works it is worth it in my opinion. Not sure you will like this option but at least it is an option! Sure, tiles would look better but will probably cost more and from what I could find they are not waterproof.

[david s]

I’m not sure of the product you are going to use, but if it is like a bathroom under tile sealer it may not contain UV protection and therefore unsuitable for outdoor use. Also be aware that any waterproofing will also prevent water escaping from the oven interior therefore creating moisture build up in the insulation layers. If waterproofing the exterior it is important to have some kind of valve or system that will allow the insulation layers to vent to the atmosphere.
Another approach which IMO is superior although more expensive and labour intensive, is not to waterproof, so the outer shell can breathe but then a roof over the oven. Also be aware that the oven can pick up moisture from high humidity even though no rain has fallen on it. In this case no exterior waterproofing will prevent its entry.

[aaronpizza]

I’m not sure of the product you are going to use, but if it is like a bathroom under tile sealer it may not contain UV protection and therefore unsuitable for outdoor use. Also be aware that any waterproofing will also prevent water escaping from the oven interior therefore creating moisture build up in the insulation layers. If waterproofing the exterior it is important to have some kind of valve or system that will allow the insulation layers to vent to the atmosphere.
Another approach which IMO is superior although more expensive and labour intensive, is not to waterproof, so the outer shell can breathe but then a roof over the oven. Also be aware that the oven can pick up moisture from high humidity even though no rain has fallen on it. In this case no exterior waterproofing will prevent its entry.

Thanks for this ill be sure to think about how it is going to lose internal moisture

I'm currently on the fence about tiling, I checked with my supplier and they said it is UV stable etc so fine for outside.

How do you usualy finish your ovens may I ask?

It will have a roof over it's head so maybe I am just over thinking

[david s]

If you have a roof over the oven I believe it’s better not to waterproof it. That way it can dry itself more easily when you fire it. Additionally you can probably dispense with a moisture valve provided you have driven out nearly all the moisture before applying the outer rendered shell.

The product I use to waterproof the outside is Flexible Pointing. This is a flexible high build acrylic product with plenty of UV resistance. designed to coat the mortar on tiled ridge caps. As a tiled roof experiences a wide range of temperatures and therefore movement, the mortar holding the ridge cap tiled often cracks, sometimes creating roof leaks. Before this product was invented it was a common job for roofers to remotest the ridge cap tiled back into place. Now they never do. Designed to be troweled on I find it way easier to apply by brush, but that requires dilution with water by 20% It contains fine sand which gives it a high build and 3 costs make a thickness of around 2 mm. It will cover tooling marks in the cement render coating, fill and bridge cracks, a wonderful product I’ve used in many other applications.

[aaronpizza]

Apologies for the lack of photos - uploading them are a pain as they are too big *huff*!
I fired the oven up, with good success, after the 7 day of curing it was easily hitting 600c+, highest I noticed was 633c.
I didn’t need to push it any hotter than that, I’ve cooked some pulled pork should for 6 hours (incredible) and cooked about 20 pizzas with no screw ups yet!
Thanks everyone for being so helpful - it wouldn’t have been possible without you all J
If anyone has any questions etc feel free to ask - I will probably be hanging out in the cooking part of the forum from now on!

[fox]

Wow 633c ...I did not even know that was possible without forced induction.
You must of built a super efficient oven.

[david s]

If you took the measurement with an IR gun it is reading the surface temperature. 10 mm deeper and the temperature will be considerably lower.

[aaronpizza]

If you took the measurement with an IR gun it is reading the surface temperature. 10 mm deeper and the temperature will be considerably lower.

Yes I used a fairly accurate IR gun, this was at the top of the oven, 100% not saturated at this temp, as it only peaked at that

Even taking photos of the oven is a pain, the amount of IR light makes all the photos a lovely shade of purple - and my phone has IR filters on it!

[aaronpizza]

Wow 633c ...I did not even know that was possible without forced induction.
You must of built a super efficient oven.

No idea ref forced induction - Certainly not needed so never looked into this...

I did put a lot of thought into every bit - an Engineers prerogative I guess! haha.

I'm sure a lot of the other ovens on here have said they've gone plenty above 600c that.
felt it was way too hot to cook pizza in, even though I have a thick base (75mm fire brick), the top cooked too fast!

*tempted to see how hot it gets now haha* - not going to as I'm sure it would break!

[sergetania]

Isn't it really awesome to see the oven you built gets that hot? There's something magical about it, at least for me. I am not saying I am a mother of dragons but...

I was actually surprised that pizza didn't burn immediately at around 900F but definitely need to reduce dough hydration for such temps.

[david s]

You will find, just like cooking pancakes, that the first one is not the best. Simply place the first pizza half in the entrance, half in the oven. Move subsequent pizzas in a little deeper. Always maintain a fire on the side and your oven will hit its sweet spot afte around the third pizza. With my oven, after the whole inside has gone white, I continue firing for about another 20 mins. Every oven is a bit different. You will soon find that you won’t be using your IT gun at all.

[aaronpizza]

Isn't it really awesome to see the oven you built gets that hot? There's something magical about it, at least for me. I am not saying I am a mother of dragons but...

I was actually surprised that pizza didn't burn immediately at around 900F but definitely need to reduce dough hydration for such temps.

Indeed we tried a pizza in at the temp and it was just too hot!

Didn't cook the center too well and the outside was well done in moments!