rebuilding mobile oven

[orionjib]

My son and I bought the original solo pizza oven prototype last year and while being delivered to Oregon was involved in an accident and the cast oven was destroyed. We had thought some of it was salvageable, but we have decided to start from the trailer base up. We have cut out a new base of 1900 degree insulating board and have purchased a few bags of Harbison-Walker 45L refractory cement. Now, what is the best way to form and cast an oven that won't be shaken apart while driving down the road. It needs to be relatively light weight (less than 500#) and approx. 36" in diameter. We are trying to figure out how to best reinforce our pour, and if in fact we are using the best suited material. Any ideas?
orionjib

[dmun]

Re: rebuilding mobile oven

GREENLITE 45 L AL is a lightweight castable, ideal for cruces, troughs and insulated back-up linings

You really need to talk to Harbison Walker on this one. There are hundred of refractory products for special applications. Usually the "light" ones are for insulating, and you need something on the inside of your dome that will absorb and reflect the heat.

Disclaimer: I don't know anything about castable refractories.

[orionjib]

Re: rebuilding mobile oven

Actually I did talk with Harbison-Walker, but folks I talked with were not very knowledgeable about pizza ovens. They recommended the Greenlite 45L because of weight and strength, but as you say, there does need to be something on the inside with reflective properties. The original oven was a cast unit made from a heavier, more dense, smooth castable with the lightweight material packed in around it with a ceramic blanket over the top of everything.

[dmun]

Re: rebuilding mobile oven

If it were me, I'd get my weight savings by using a pre-cast refractory oven like the ones Forno Bravo sells. They are thinner than anything you can make from brick, they are strong enough to stand up to some vibration, and cost is a secondary consideration, since a mobile oven is usually for catering, and you can factor the costs into your product. Also, they're tested and proven. You aren't playing with unknown weird refractory products when you could be making money selling pizza.

I agree about the general helpfulness of the H-W staff. My local branch here in NJ was less then helpful. You may want to contact their headquarters and ask to speak with an applications engineer.

[orionjib]

Re: rebuilding mobile oven

Getting a precast unit might work, but I think the Forno ovens will not fit into my stainless steel enclosure. There are other manufacturers, but I'm having trouble locating them. Months ago a local masonry company gave me a name of a company who made a casting that doable, but I am unable find them now. We haven't had much luck getting the specific info we need from Solo. I think they are guarding their trade secrets, which is understandable.

[dmun]

Re: rebuilding mobile oven

I don't know how much smaller than a casa 90 you're going to get and still have a workable cooking floor. It is slightly heavier than your five hundred pound limit, but again, that is mass you need for wood fired cooking.

[SpringJim]

Re: rebuilding mobile oven

90 would be pretty small, particularly for catering with a mobile.

How big was the original oven?

[asudavew]

Re: rebuilding mobile oven

I have to agree with Dmun.
I was thinking the Casa coated with mortar and insulation, to help retain heat.

How about brick, with chicken wire and mortar coating the whole thing?

[SpringJim]

Re: rebuilding mobile oven

How about brick, with chicken wire and mortar coating the whole thing?

I have to tell you my first thought was Craig's ferrocrete project....

[orionjib]

Re: rebuilding mobile oven

Looking at the casa90 dimensions, I might fit albeit a bit pricey. We are starting this thing on a fat shoestring. Tell me more of Craig's ferrocrete project. Our problem is that the oven needs to fit within a SS enclosure that already has a door opening and chimney flue. We can make some modifications, but we are limited by overall dimensions.

[Groves]

Re: rebuilding mobile oven

What's the latest on your mobile oven? Don't leave us in suspense. Don't you realize that you're holding the rest of us back who are waiting to learn from your success. Did you end up casting one?

[orionjib]

Re: rebuilding mobile oven

Sorry for the delay, I had forgotten I started the thread months and months ago. I'm glad you rattled my cage (or oven). Yesterday we finished casting the walls of our oven, and it was quite a process. After some trial and error we hit upon wiggle board plywood as our form building material. It is special plywood (we used 3/8") that has each ply oriented the same direction so it is very flexible. You can bend a big piece in a 3" radius if you like. Then using a little high school geometry we made 2 segments of cone forms (inside and outside walls) did some elaborate bracing and poured/packed in our castible. On our first pour a week ago, I miscalculated how much castible to buy and we ran way short. This necessitated splining the top of the first pour with brass spline/keys and making a second pour using a refractory cement as an adhesive.We are now in the process of making a dome lid form. I made a template platform the size and shape of the oven top and used thin strips of wood (1/16" x 1/2") and arched them over the platform forming a dome skeleton. Over this we paper mach?d a skin to make our mold. next week we will finish pouring the lid in place on the oven and we will about be ready to fire it up. As for product, we stuck with Harrison-Walker. We used KS 4V Plus for the oven structure and Sairset as the adhesive to make a good bond between pours. We have Greenlee 45L to use as a insulated filler around the oven, but I don't think there will be room for much. You don't have to tell me how much work this has been. I'm painfully aware, but what a learning experience. I'll keep you posted as to our progress and can include a few pictures if you like.
jim

[Groves]

Re: rebuilding mobile oven

It's perfectly fine to delay. I'm just grubbing for some good info, stories, and progress reports. Thanks for taking the time.

As for future updates and pictures? Wow, you need not ask. We'd all love them I'm sure!

Thanks again.