30" cast dome design

[danhem]

danhem Thanks!
Wrapping in plastic usually leaves an imprint on the surface, doesn't it? Also, did you moisten the perlite layer before applying the stucco? That adds some water back in but I guess not that much.
I don't mind just watching the fires at all(a beverage of choice helps). It's quiet time. Once the oven is ready and you have to make pizzas it's over!

I didn't have an issue with an imprint. The plastic is naturally smooth and I didn't pull it too tight - just made sure that no moisture could escape. At the end of each day I smoothed the plastic back over the surface and any condensation went back onto the stucco - whether that helps or not I have no idea.

I used vermiculite instead of perlite and left the layer to dry out for around 4 weeks. With that in mind I didn't want to add moisture to the v-crete as it seemed counterintuitive. I guess that the v-crete will absorb some of the moisture from the stucco helping with the bond. David S warned that excess moisture would steam during a fire, which could cause some cracking so I was very cautions to keep the v-crete layer as dry as possible.

[sergetania]

danhem Thanks!
Wrapping in plastic usually leaves an imprint on the surface, doesn't it? Also, did you moisten the perlite layer before applying the stucco? That adds some water back in but I guess not that much.
I don't mind just watching the fires at all(a beverage of choice helps). It's quiet time. Once the oven is ready and you have to make pizzas it's over!

[danhem]

David

How much fiberglass fibers do you add to stucco mix? I got a small bug that came without directions. Thanks!

Hi,

I followed David's advice also and use the AR fibers, I just mixed up a bucket of stucco and threw a couple of handfuls of the fibers in. I'm Sure David will come back with a more precise formulae, but my stucco has set really well and after a couple of full blown fires no cracks have appeared.

I did the scratch/brown coats and wrapped the dome in plastic for about 8 days until the condensation was no longer visible on the inside of the plastic. I think this process along with the AR fibers helps the stucco to cure and set strong. Providing you have driven all moisture out of the oven and perlite your stucco will be crack free.

Being patient is the real killer here, especially as you have now seen your first fire. In all honesty I am addicted to lighting and watching fires in the oven. As you progress through the curing and the fires get bigger....boy you are in for a real treat there .

Good luck.

[sergetania]

Do not use a concrete mix for your render/stucco mix. Concrete is that hard thick stuff containing large aggregate and usually 100 mm thick, composed of sand, water cement and aggregate. What you are talking about is a cement based render/stucco comprised of sand water, hydrated lime and cement to be troweled on in around 2 or 3 5mm layers (I do mine in one 10-15 mm layer reinforced with AR fibreglass fibres).

David

How much fiberglass fibers do you add to stucco mix? I got a small bug that came without directions. Thanks!

[sergetania]

I have to admit - the first fire is a sight to behold! Enjoyed it a lot!

[sergetania]

Haha! Got a ceramic egg grill, similar risk. Considering that hair have become somewhat sparse, definitely nothing to be taken lightly

[Gulf]

.........it should be able to extinguish the fire when shut.

Be careful! I haven't found much reason to extinguish a fire in a WFO other than making lump charcoal. But, If you do, don't open the door for at least a week. Underwear is replaceable and hair will grow back, but the smell will stay in your memory for a lifetime .

[sergetania]

Watching perlite concrete dry is so exciting... So I made a (semi)shiny door. I think the fit is pretty decent and it should be able to extinguish the fire when shut.

[sergetania]

I feel like I am! Be patient,cure,mix stucco with all kinds of hi-tech stuff and smear it on...in layman's terms

Thanks, David, hope you are out of the hospital and back to normal... Whatever that is these days!

[david s]

Yes, now you’re on track.

[sergetania]

David

I meant a commercial base/brown coat mix,not just a concrete mix. I think that's what you are talking about. I also ordered an acrylic bonding agent that I will use for part of the water in the mix. Now I will also get the AR fiberglass fibers like you said for reenforcement and do it one layer. Thanks!

I understand that I need to dry/cure the oven first. Thanks again!

[david s]

Do not use a concrete mix for your render/stucco mix. Concrete is that hard thick stuff containing large aggregate and usually 100 mm thick, composed of sand, water cement and aggregate. What you are talking about is a cement based render/stucco comprised of sand water, hydrated lime and cement to be troweled on in around 2 or 3 5mm layers (I do mine in one 10-15 mm layer reinforced with AR fibreglass fibres).

[SableSprings]

Sergetania, don't worry about patching the strap damage...you've got great insulation. The perlcrete is primarily to give you a more solid base for the render and to help give you a nice, smooth dome shape. As Mullster & UtahBeehiver have noted, you have a long way to go to drive out all the moisture...so making sure it's securely protected from rain is really important right now. Also, when you put a tarp over the oven, make sure your base hearth is covered so water doesn't seep in at the base perimeter seam of your oven.

[sergetania]

Mullster Thanks for the encouragement! Sometimes it's all it takes
This build was going way too smoothly till this step. So this is a good learning experience, hopefully,and nothing that needs to be redone.

Wondering if I need to patch the layer in a couple of places where I had the strap or just do it with the render.

Definitely have a plastic cover. It's a hurricane season and while they reach us weakened they still dump a few inches of rain in a day. Cheers!

[Mullster]

Got it, will wait, cure,then render. Thanks!

What about some crumbling pieces of the perlite layer? Knock them loose? How do I know if it's good enough? What if I knock off too much? Should I add more on top? Or do I fill any voids with render applying the next layer?

Definitely no expert here but having got through stage recently thought I’d chip in. I used vermicrete for the insulation layer. Yes it was crumbly. Once it once on and dried for a day it didn’t feel like it would fall apart but equally I could fairly easily flake small pieces off if not careful. For me the key thing was to protect this layer whilst getting through the curing - hence the use of plastic covers and later on a temporary roof shelter. It was several weeks in the end before I started the render layer and indeed I haven’t fully finished yet because there’s no longer a rush (temporary shelter) and every fire is just serving to drive more moisture out.

I personally don’t think the integrity of the layer you’ve built is a big problem - but you probably do need to keep it protected from the elements while it’s drying out.