winter cooking ?

[Acoma]

Re: winter cooking ?

Dave, I am not sure if less mortar gives less cracks. We need to have a tally on cracks with little and mass mortar applications. I have mass on the back so we will see with mine.

[Frances]

Re: winter cooking ?

I remember a couple times at the end of a batch of mortar that seem to drying out and now I'm worried about that.

Half of the building process seems to be worrying that you've done something wrong somwhere - I know mine was... (and still is for that matter). So don't worry too much about worrying. I'm sure your oven will cook beautifully.

The longer I'm in this forum, the more ovens I see being built and the more I fire up my own oven, the more I admire these oven plans. Simple, flexible, functional, brilliant. These are really cool ovens, with or without cracks, and don't you doubt it!

Acoma, interesting you should say that. I can't really see why less mortar should equal less cracks either. I can appreciate the beauty of exactly measured bricks and the skill of building a near perfect, near mortarless dome - but does it actually cook better or crack less? ...from a gut feeling I'd say it might last longer, and be more stable. I dunno, maybe not. Its certainly an interesting subject to follow up.

[asudavew]

Re: winter cooking ?

Well .. my reasoning...


Less mortar = more bricks.
Which ,in my brain, means expansion and contraction would be more uniform. (I'm probably wrong here)
With lots of mortar and less bricks, less uniformity. The bricks expand and contract at one rate, while the mortar at another.
I think that would lead to more stress and more cracks.

But that is just what I was thinking. It sure doesn't make it true

Dave

[gjbingham]

Re: winter cooking ?

That's an interesting idea Dave, but I'm not sure if that's the case regarding a dome. If the coefficient of expansion of the bricks and the mortar was exactly the same, you would still have thermal expansion of a rigid half-sphere as it heated. It seems to me that unless the whole thing is floating, something's going to give (crack), somewhere.

My thinking - probably way off too. Where's dmun?

[Acoma]

Re: winter cooking ?

I was thinking of this because some of us apply, or plan to apply cladding of an inch around the outer dome. This has its own expansion rate too, right? If the cladding is not an issue, and the back side of the brick has thin or thick mortar, then I see no difference. I might even feel that thick mortar on the back helps to prevent the cracks, but I am sure argument will follow to this.

[asudavew]

Re: winter cooking ?

Hey Rob.
I would stay away from cladding to much.
I had mortar on the outside of my dome.... Maybe a 1/2 inch or so on most of it. I just kind of added it as I built the dome.

My heat up times push 2 hours!, On the other hand, my oven does retain heat well. A trade off.. Longer heat up times... longer retention...
Just do what would fit best for you.

If you don't mind longer heat up times go for it!


As for cladding to avoid cracks, I've wondered if adding chicken wire over the dome(nice and tight) and then cladding over the wire and dome would help to prevent cracks.
Kind of a reinforced outer layer.

What do you think?

Your oven is looking great by the way~!

Dave

[gjbingham]

Re: winter cooking ?

Didn't you get your bricks at the same place Dusty did?

You could just hold off a bit and see how long Dusty's takes to get heated, then decide on the cladding issue. As you know, I put at least an inch on mine, and I can get the dome white in an hour +/-.
G.

[RCLake]

Re: winter cooking ?

Didn't you get your bricks at the same place Dusty did?

You could just hold off a bit and see how long Dusty's takes to get heated, then decide on the cladding issue. As you know, I put at least an inch on mine, and I can get the dome white in an hour +/-.
G.

What type and how much insulation do you have over your dome. I picked up mine yesterday, 50 sf of 2" and also of 1". So I'm hoping that will be plenty.

[Acoma]

Re: winter cooking ?

I am going with an inch of cladding, then 2 inches of the blanket, then Matrilite18. True that heat up will be longer, but the goal is to maintain the heat so that I focus more on the fun then the fire.

[gjbingham]

Re: winter cooking ?

RC,
I used two rolls of 1 inch thick, (50 sq. ft each) over mine. I got at least two inches thickness around the sides, mostly 3 inches, and up to 5 inches on the top of the dome.

They say you can't over insulate. What kind of finish are you planning for your oven??? Mine's a bit mishapen because of the variances of thicknesses of blanket on it. Sounds like you have more than enough blanket to suit your needs.

George

[CanuckJim]

Re: winter cooking ?

George,

Those wishing to have a symetrical igloo shape for the finished oven might try this approach: apply the blankets, then chicken wire, then a thickish layer of either vermic/Portland or Matrilite 18. I use Matrilite 18 because it's a better insulator at about the same price. Either material can be a bit tricky when trowelling onto near vertical surfaces, but have a spray bottle handy to dampen the blanket as necessary. Once you get the hang of it, it's not difficult to even out bumpy or low spots in the blanket layer. Even if some remain, you can fill them in the next day, once the material is set but not completely dry (alternately, you can dampen it, then apply additional). After that, you can use a stucco prep coat like Durex Monobase and finish with an exterior stucco. Treated this way, the igloo will not only have superior insulation, but it will be very weatherproof, maybe almost bulletproof. I'll post a pic in the gallery shortly.

Jim

[gjbingham]

Re: winter cooking ?

Thanks Jim,
I did a number of searches for the matrilite 18 on Google, Yahoo etc. I couldn't find much at all, and certainly no distributors.

I went with vermiculite/concrete over chicken wire (and blankets), then stucco. I'm pretty close to symetrical, but certainly not perfect. You can't really tell unless you walk around it and specifically look for asymetry.

George

[CanuckJim]

Re: winter cooking ?

George,

I thought I posted this link at one time or other, but maybe not. Look at: Manufacturer of refractories and supplier of refractory services for the aluminum industry - Matrix Refractories . Matrix is the Refractories Division of Allied Mineral Products. This is a global company, and the North American headquarters is in Texas. They do have a list of products and distributors.

Jim

[gjbingham]

Re: winter cooking ?

Oh yeah,
I'd forgotten, you did. After looking around that site, I found matri-everything except matrilite. Maybe I didn't pursue it hard enough. Good resource for others though.

George

[RCLake]

Re: winter cooking ?

RC,
I used two rolls of 1 inch thick, (50 sq. ft each) over mine. I got at least two inches thickness around the sides, mostly 3 inches, and up to 5 inches on the top of the dome.

They say you can't over insulate. What kind of finish are you planning for your oven??? Mine's a bit mishapen because of the variances of thicknesses of blanket on it. Sounds like you have more than enough blanket to suit your needs.

George

Well my thoughts are very fluid right now. It will be stone structue at the end like this photo, but just as this has taken time, I'm wondering about a temporary sollution. After the dome is done(hopefully soon!) I'll do the curing, put on the ceramic blanket and I'm wondering if I'll stucco over it to weather protect it? One reason I may not do this I won't be able to add insulation later.