baking expert seeks oven expert. MHGSOH!!

[michaelthebaker]

hi everyone, finally got round to registering after many times reading very interesting threads. i don't do forums, apart from dan lepards excellent baking forum, so i'm a real novice and technophobe. but i've been baking professionally for over 30 years, following in the footsteps of father and grandfather, so i consider myself to be a very knowledgable bread baker. i am retired, only 45- baking is a hard life, and for the past few years have been building clay bread ovens at fesivals, gatherings etc, a real hippy- so my friends say. i call myself a sacred baker.

well my new project is to build a concrete pizza oven on a trailer to tow behind my home- a converted mercedes bus- yes really! i have done lots of research, seen the veraci pizza site and links. but i still have a number of questions, some very specific, but it seems you lot are the most knowldgeable anywhere so here goes.

the veraci pizza oven is supposedly adobe, correct? looks like some cement to me, as if adobe surely it would shake to pieces on the trailer.

using refractory cement should i strengthen it with steel, mesh, wire.

the weak point i think is where the oven shell connects with the hearth, any ideas on stopping breakage here.

the trailer is gonna be a 2nd hand caravan chassis. i believe the oven and hearth will weigh less than a ton. any ideas on suspension and stopping it all falling to pieces.

i look forward to hearing from you all, and thank you in advance. i dont often have net access living in the bus so i apologise if my repsonses take a few days, i am not ignoring you, just awol in the woods.

i will of course be posting on going pictures and stories, when i learn how to download pics and upload onto the net

hope that you all achieve everything you aim for in 2008. best wishes

michaelthebaker

[Dutchoven]

Welcome to the forum!
Hmmm! Have to think about this one a bit! My opinion on the reinforcement is Yes! Will you only be making bread or will you be doing pizza also?
Dutch

[michaelthebaker]

hi dutch. want to be able to bake many things, so need quite alot of mass in the hearth and oven walls to to bread and longer cake baking and meat roasting when oven iscooler. getting trailer with 1.5ton rating so my calculations on cement density/volume indicate i can have hearth 6-8inches, including vermiculite, and walls 5-7inches thick. strength is my main concern, as i dont want to see my livelihood fall to pieces behind me as i am driving down the road.

all comments much appreciated

HOME IS WHERE THE HEARTH IS

[n2iko]

Vermiculite concrete might not be the better choice here, look into the ISOL type bricks. There is going to be a lot of vibrations even when the trailer is sprung well.


--mr.jim

[Dutchoven]

I agree with mr.jim...I think insulating firebrick would be a better choice for the trailer application as the vermicrete that I have seen stays quite flaky...I think they are also a bit lighter in weight although with a trailer rated for the load you speak of that is not a worry...I might suggest an Alan Scott type oven if that is not already what you were thinking of...using that type you might create a steel harness around the upper walls before cladding and then insualating...the bounciness of the trailer might have a greater effect these since that is where the thrust of the dome enters the walls
Self taught hearth bakers is what we are...what experience do you have with Pumpernickel? Have made attempts at it and the flavors were spot on but made some errors in technique and got frankenstein loaves.
Will continue to share my thoughts on your project!
Best
Dutch

[Acoma]

You may be better of with some type of plate assembly oven than brick due to roads and vibrations. Your brick and mortar may hold for a few travels if all went well, but you would not want to be at some gathering, show up, and have unstable bricks cracking everywhere. FB has modular ovens that to me, seem best for such travels. Also, call their 800 number, ask for their engineer, and see if it would work.
You could also call this company that does portable oven parties.

two

[cvdukes]

A fully wire-reinforced concrete stucture shell can take an a lot of vibration. For case in point, look at how ferro-cement boats can take pounding seas where other boats break up.

Also, to minimize vibrations, get away from the idea of using standard leaf springs and shocks on the trailer. Springs between the axle and wheels are okay, but for minimal vibrations, you'll want to extend the sides of the trailer up above the level of the hearth floor and basically suspend the oven with paired shock absorbers at each corner. Countweights and damper systems can help if you get them right, otherwise they could cause greater oscillation.

[michaelthebaker]

thanks for all your suggestions. going to see some mechanical design friends this weekend for a design blitz, will put all your ideas in the mix and see what arises.

PROOF IS IN THE PUDDING

[dmun]

I'm a little concerned about the re-inforced concrete idea. Regular mesh/re-bar re-inforcement isn't used with refractory concrete because of the large temperature variations in ovens: the big difference in co-efficients of expansion between the masonry and steel can set up stresses and cause cracking and failure. Cast refractory is re-inforced with stainless steel needles.

Someone correct me if I'm wrong, but I don't think anyone here has built an entire dome out of refractory concrete, except for Ed Schmidt's geodesic. We've seen plugs for the top of the dome, and flue funnels. Would these withstand bouncing around? Refractory concretes aren't as strong as portland cement based concretes.

Once you start springing for castable refractories, and stainless needles, you're talking about serious money just in materials. It may pay to look at the pre-cast modular ovens, that have been successfully used in mobile catering ovens. They are much stronger, and less prone to cracking in ordinary service.

[CanuckJim]

Michael,

Have a look at this site: http://www.thefirewithin.biz/Home.html. Joseph uses FB modulars for his portable ovens.

Jim