FINALLY!!! - Start Of Building My Oven

[david s]

Re: FINALLY!!! - Start Of Building My Oven

Yes you should do the vermicrete and then drive out all the moisture slowly, but the vermicrete will be crumbly, I wouldn't leave it for a couple of months, maybe a couple of weeks, if possible and don't let any rain get on it in the meantime.

[Oven_Man]

Re: FINALLY!!! - Start Of Building My Oven

Hi David

I've wrapped the oven with the Ceramic Blanket. I never knew how irritable that stuff can make your skin when touched.

Never the less, I never expected wrapping the oven would be such a challenge.
I wrapped Chicken Mesh wire oven the blanket and that was a little disaster as the wire kept catching on the blanket and ripping pieces off. Anyhow, I filled any gaps with more pieces of blanket and all looks good so far.

Tomorrow I add on Vermiculite. I know you mentioned no need for sand in the mix but if you were to suggest the least amount, how much would it be? I just want to add a little strength - remember when I laid my vermiculite floor, I used sand because of strength and I found the material easy to work with - I'm sure without sand the Vermicrete is difficult work with.

By the way, the only reason I don't want to stucco right away is because I plan to redo the vent at little later - don't have the energy now - I'm too anxious now to get this thing up but I'll take some pics of my current vent - I'm sure you'll be able to help me fix my current design.

Thanks again for everything
Regards
OM

[david s]

Re: FINALLY!!! - Start Of Building My Oven

Ok, if you must add sand then go ahead. The blanket will do a good job of insulating. How thick is your blanket layer? The primary reason for the vermicrete layer is together the shape back to a hemisphere neatly anyway. Just add enough sand to make it nicely workable. It does make the mix easier/better to apply.

[Oven_Man]

Re: FINALLY!!! - Start Of Building My Oven

The blanket is 50mm thick - 25mm wrapped around the oven twice.

Just out of curiosity, is ceramic fibres a Health Hazard. The reason I ask is when working with it, I wore a silk cloth over my face but it was difficult to entirely prevent those fibres from my face - I'm just worried I may have inhaled some - sorry, I know this is not the forum to ask this type of question but I'm just the paranoid type.

[david s]

Re: FINALLY!!! - Start Of Building My Oven

Insulation thickness is fine then. You're good to go.

The blanket is not considered safe. It is classified as a class 2 carcinogen ie it has created tumors in rats but so far not recorded cancers in humans (yet)
I work in a school and we are not allowed to have any ceramic fibre in our kilns because children are considered more susceptible.

Read this
http://www.unifrax.com.au/msds/Fiberfrax%20Paper.pdf

[Oven_Man]

Re: FINALLY!!! - Start Of Building My Oven

Wow, that's scary.
I guess if you work with this stuff daily, you are at risk but for someone like me who only uses is once off - it may just create some short term effects - like my sinus is activated after working with it.

Anyways, I will still take all the precautions I need to - thankully I was working in an open ventilated area.
The only concern is I left it in the house in a plastic packet - I need to go and get it out.

Is it safe to use in a pizza oven considering you said you're not allowed to use It in a kiln?

[david s]

Re: FINALLY!!! - Start Of Building My Oven

Once it is installed there should be no way the fibres can escape.

[Oven_Man]

Re: FINALLY!!! - Start Of Building My Oven

Oh thank goodness - thought I would have to rip out the Ceramic Blanket

Anyways, I managed to cover half the dome with Vermicrete - damn it takes long - I just got tired and had to stop. I used the mix ratio 1:1:8:3 Sand:cement:Vermiculite:water

The product still was not very easy to handle but I managed to place it on. Now I understand why you said I won't be able to leave it like that for a few months, leave a few months - I don't think I would leave it a few weeks. It's very crumbly and the slightest touch causes it to fall.

So, now that I would need to stucco immedietly after vermicrete, I need to find the best way to do it.
I remember asking quite a few refractory suppliers and hardware stores for stucco but no one seems to have heard of it. They probably have another name for it and I just can't explain to them what it is. Is this stuff easily DIY? Maybe I should just make it myself.

I was wondering, do I need to add refractory cement along the archway of my opening?

Thanks
OM

[david s]

Re: FINALLY!!! - Start Of Building My Oven

Assuming the vermicrete doesn't get rained on, leave it for a week to dry, then try 4:1:1 sand, cement, lime mix and cover it with cling wrap for a week so it damp cures.

[Oven_Man]

Re: FINALLY!!! - Start Of Building My Oven

Perfect! My oven is under a shelter so no rain should come close to the Vermicrete.

Thanks for the Stucco Recipe.

1. I've never worked with Lime before. Is it the same stuff you get in Gardening Stores?
2. How thick should I go with the Stucco?
3. Do I fire cure the oven before or after i Stucco?
4. Now I'm on the lookout for Pizza Tools. I'm contemplating between buying and having them custom made. I more or less know most of the tools but there's one that I'm not sure how it works. It's the round peel found here Pizza Tools | Pizza Peels | Pizza Oven Tools . Does this thing have a lever of some sort that you press and it rotates the pizza 180 Degrees? Any clue how this works?

Thanks
Regards
OM

[david s]

Re: FINALLY!!! - Start Of Building My Oven

Perfect! My oven is under a shelter so no rain should come close to the Vermicrete.

Thanks for the Stucco Recipe.

1. I've never worked with Lime before. Is it the same stuff you get in Gardening Stores?
2. How thick should I go with the Stucco?
3. Do I fire cure the oven before or after i Stucco?
4. Now I'm on the lookout for Pizza Tools. I'm contemplating between buying and having them custom made. I more or less know most of the tools but there's one that I'm not sure how it works. It's the round peel found here Pizza Tools | Pizza Peels | Pizza Oven Tools . Does this thing have a lever of some sort that you press and it rotates the pizza 180 Degrees? Any clue how this works?

Thanks
Regards
OM

1. No, you need builders lime
2. Two layers about 10 mm thick each (24 hrs between coats) should work well.
3. Cure before stucco.
4. No special lever, you learn to lift the pizza and rotate it by giving it a slight twist.

[Oven_Man]

Re: FINALLY!!! - Start Of Building My Oven

Thanks.

Another question just popped in my head - do I need to line the inside of the Opening Archway with Blanket or can I leave it just as it is - refractory only.

[david s]

Re: FINALLY!!! - Start Of Building My Oven

No insulation on the inside, but you can insulate it over the top.

[Oven_Man]

Re: FINALLY!!! - Start Of Building My Oven

Hi David

I will be hopefully finishing the Vermicrete layer this weekend. Once complete, I'll leave it till next weekend to dry.

Next is to cure it. With regards to curing, I remember reading the curing fire should be lit over a period of 6 days starting with a small fire on the first day and increments each day after.

Do these fires have to be lit over 6 consecutive days or is it fine to break it up over 2 or 3 weekends. The reason is I only have access to the Oven on the weekends.

Thanks
Regards
OM

[david s]

Re: FINALLY!!! - Start Of Building My Oven

It is fine to leave it after only partly cured, in my opinion. In fact you could argue that it is better to do it that way because the moisture gets driven off at the top of the dome first while the base is still fairly cool and moist. By leaving it the oven has a chance for the moisture to migrate back up to the top again, so when you re-fire there will be less of a temperature difference between the top and the bottom of the oven. The same would happen with the floor where the centre will get hot and dry before the outsides.It will take a lot longer than 24 Hrs for this moisture to even out throughout the structure so waiting longer is not a problem.