My latest precast oven, struck today

[sonomacast]

Re: My latest precast oven, struck today

And the view from the rear. All concrete is 3" (75mm) thick

[david s]

Re: My latest precast oven, struck today

Someone else reported difficulty fitting the last piece with a different modular cast oven. This is probably because you need to account for the lost space created by the divisions in the mould.To do this you need to increase the division thickness slightly for the last top section, making it slightly smaller. Then all the sections will fit perfectly. Mine fits in as a conical form rather than using a step. This also helps in the fitment.I've been down this road and it takes time to get your mould working just right. Hope this helps, your dome looks like it fits together pretty well to me.

[sonomacast]

Re: My latest precast oven, struck today

There was no lost space, Basically I formed the mold in total then divided it into the segments. I poured every other segment one day, removed the stop ends, waited 2 weeks to allow for any shrinkage and poured the remaining segments minus the capping stone. I poured the capping stone last (It is conical in shape). here is my oven before I seperated the segments

[david s]

Re: My latest precast oven, struck today

Ok I see. In that case the sections should fit together exactly.
You do not have to wait for two weeks with calcium aluminate castable. It is a different chemical reaction than Portland cement concrete. You only need to cover it as soon as you've finished placing it, wait 24hrs, then remove it from the mould. Also there should be no shrinkage, providing you have added the required quanTity of water.

[sonomacast]

Re: My latest precast oven, struck today

Well there was no hurry. I am still trying to figure out how to fit it to my trailer safely, Any ideas??

[david s]

Re: My latest precast oven, struck today

my mobile sits on a slab of aerated concrete and I cut into it with an angle grinder so the base of the outside shell bonded to it. the only thing holding the inner oven in place is the mortar between it and the base and the vermicrete between it and the outer shell. It has actually held together remarkably well and probably way better than I expected. Been over lots of bad road, potholes and speed bumps. I secure it in my trailer with chains and turnbuckles. The weight of the oven seems exactly right for my trailer springs, which was pure fluke. I do not have shocks, although I have been intending to fit some for the past few years. Because mine is on a single axle and the weight is pretty much over the axle, the drawbar has gone skywards a few times at about a 45 degree angle. The oven stayed in place beautifully with no noticable movement or damage. Have since altered the ovens position, moving it forward slightly. This was really easy because its rolled on in a trolley so I only had to alter the lengths of the securing chains.

[Lburou]

Impressed!

Well, I'm certainly impressed

From time to time I'm humbled by the product of a real craftsman. I'm humble now. Everybody doesn't have the talent you demonstrate with your oven. An awesome display of persistence, coupled with uncommon skills

Congratulations. Can't wait to hear how well it works.

[sonomacast]

Re: Impressed!

Well, I'm certainly impressed

From time to time I'm humbled by the product of a real craftsman. I'm humble now. Everybody doesn't have the talent you demonstrate with your oven. An awesome display of persistence, coupled with uncommon skills

Congratulations. Can't wait to hear how well it works.

Thank you very much for the fantastic accolade. I feel like I have won the oven Oscar, cheers all

[bgreed]

Re: My latest precast oven, struck today

The oven looks great. If you don't mind just a couple of questions.
1. how tall is the wall before it turns to become ceiling?
2. why did you set your oven on the floor rather than surrounding the floor with the oven walls which should be more heat efficent?

Thanks

[sonomacast]

Re: My latest precast oven, struck today

I weighed up the pro's and con's on forming the floor inside the oven or sitting the oven on the floor and decided the easiest way was to sit the oven on the floor (I was originally going to use bricks for the floor and decided it would be too difficult to cut them in the perfect circle to fit, I researched the loss of heat by using this meathod and it is no different, I intend to wrap the entire oven in insulation anyway. However next time I shall probably sit the oven over the floor (As I have done with one of my other ovens) Thank you

[david s]

Re: My latest precast oven, struck today

"decided the easiest way was to sit the oven on the dome"

Don't understand, did you mean sit the oven on the floor?
I think for a mobile oven that this is the best way because at least it holds most of the floor in position rather than lots of loose floor bricks bouncing around inside the oven during travel.
Just cooked 58 90 sec to 2 min pizzas last night in my 21" mobile for our annual school Spring Fair. The pizzas were a hit, but unfortunately as I was cooking them one at a time, and we were swamped with orders, some people had to wait up to 45 mins for that last pizza.

[casper]

Re: My latest precast oven, struck today

That looks great, but I am wondering why you made it so big if you want to keep it portable.

I suggest you keep this in your back yard and make another to fit on a trailer... which you would need to be braked double axle to prevent it tipping.

This is the FB insulation board link
http://www.fornobravo.com/PDF/FB_board.pdf
as you see it is 3 to 4 times better than vermiculite so is much lighter and compact.
You can get it for less than 80 quid from a refectory builder's yard. My local one has offcuts which I collect from time to time, no charge/beer money

[casper]

Re: My latest precast oven, struck today

That looks great, but I am wondering why you made it so big if you want to keep it portable.

I suggest you keep this in your back yard and make another to fit on a trailer... which you would need to be braked double axle to prevent it tipping.

This is the FB insulation board link
http://www.fornobravo.com/PDF/FB_board.pdf
as you see it is 3 to 4 times better than vermiculite so is much lighter and compact.
You can get it for less than 80 quid from a refectory builder's yard. My local one builds and repairs smelters and sometimes has offcuts, no charge/beer money.
They have tapered firebricks too, makes the circles easy.

But all this is too heavy for a portable oven, u only need 2 inches on the floor and 2.5 on the roof, unless you are making constant pizza or 150 loaves a day in which case 3" is not enough, better with twice that

[sonomacast]

Re: My latest precast oven, struck today

I origionally set out to build the best ven i ould and after many months of reading material on the subject I opted for this, The trailer is an afterthought, I have purchased a used tandem trailer and my local trailer builder (Wessex Trailers) say it will take the weight as long as I am careful going around corners. To be honest I don't know what to do with it. Cheers
Also before I set out to build this oven I called several reps for refractory companies and they said 75mm should be the absolute minimum thickness better to be 100mm and I didn't want to take any chances.

[aiannar974]

Re: My latest precast oven, struck today

Sonomacast - do you have any pictures of the mold? I am having a tough time understanding how you cast it in one piece and still made the pieces interlock.

Anthony