#11  
Old 10-01-2011, 02:34 PM
david s's Avatar
Il Pizzaiolo
 
Join Date: Mar 2007
Location: Townsville, Nth Queensland,Australia
Posts: 4,737
Default Re: Preparing for steel oven build.

If that was my set up I'd be including some gussets or diagonal bracing on the stand legs that attach to the trailer chassis.
Reply With Quote
  #12  
Old 10-01-2011, 02:49 PM
Master Builder
 
Join Date: Mar 2008
Location: Washington State USA
Posts: 777
Default Re: Preparing for steel oven build.

Scarnucci,
Regarding the strength of the vermicrete: terrible in tension, better than terrible in compression but not much better. One could get really complex in designing so you have little or no heat loss in your hold downs/anchors.

Realistically (IMHO) what you want is something that will keep everything together when you are forced to do a panic stop. You most likely will be driving conservatively otherwise and so therein lies the grey area between what is enough and what is not.

An idea:

A plate of steel welded to the steel dome at each end of where the underneath supporting cross member is located. This plate is maybe something like six inches long by three inches wide and maybe 1/4 inch thick. It is welded horizontally up from the bottom of the dome where it will eventually be embedded in vermicrete. This small plate has a one inch hole drilled in it. The hole is located in the plate so that it will not be embedded in the thermal mass when the plate is welded to the dome. Thru this hole there will be a 3/8ths inch bolt which is welded to the tray support so the threaded end is upright. This bolt will be long enough so that when assembled it sticks up thru the hole in the plate by an inch (minimum). Locate the steel dome when assembling the oven so the bolt passes thru the hole but doesn't touch it. Once the dome is set upon the bottom bricks and before you pour the vermicrete thread a large nut onto the bolt. This nut can be constructed of a large fender washer welded to a regular nut, the idea is to make it so that the bolt cannot come thru the hole when attached yet the interstitial space between the bolt and nut assembly and the small plate is filled with vermicrete. Thus you have the thermal break and yet the dome is less likely to part company with the trailer when you (hopefully never) have to make a panic stop. The bolt should be a grade five...no need springing for the extra cost of a grade eight as when you weld it the heat treating will be lost and grade fives are basically grade eights without heat treatment. The weak point is the weld between the bolt and the support but hopefully some of the energy will be taken up by the compression of the vermicrete in the hole before the load is transmitted to the bolt, bending the bolt before transmitting enough energy to break the weld.

Just my thoughts and first thoughts at that. No liability as to failure, take it as worth what you paid for it...which is nada.

Hope this helps,
Wiley

Also, when I grind anything that makes a lot of dust I always try to set up my large shop vac so that the intake is where the grinder will be throwing the waste. Helps a lot to keep the dust from going everywhere.
Reply With Quote
  #13  
Old 10-14-2011, 05:22 PM
Serf
 
Join Date: Aug 2008
Location: Indianapolis
Posts: 19
Default Re: Preparing for steel oven build.

Thank you for your comments and suggestions for welding the dome in place.

I cut some bricks today and picked up the dome from the fabricators.

Some pics of where I am at:

Bricks are not locked down yet, obviously. The 2X4s are in place where a vermicrete mix will go. I'll probably end up welding some bolts in the middle of that area and then some plates from the bolts to the dome, as per some suggested.



More or less where I want the dome at.







I stopped by a local refractory fire brick factory on my way from picking up the dome. Talked to them about layering the dome in two inches of refractory cement, then insulating it. He is also into pizza and pizza ovens and suggested that the refractory be on the interior of the dome. As this is mobile, I dont really want that. He doubted the effectiveness of any refractory on the outside of the dome, and suggested that I just insulate the hell out of what I have. That the insulation and shape of the dome will keep blasting the heat downwards towards the brick floor which will absorb and hold the heat.

So, I am considering building 4 walls up from the existing frame, and making a square enclosure for the dome. Wrap the dome in 607 super wool, then fill in the remainder of the area inside the enclosure with vermiculite. Wall it off, roof it, call it done.

Is there any chance at getting away without the refractory?
Reply With Quote
  #14  
Old 10-14-2011, 06:24 PM
Master Builder
 
Join Date: Mar 2008
Location: Washington State USA
Posts: 777
Default Re: Preparing for steel oven build.

"Is there any chance at getting away without the refractory?"

Little to none IMHO especially if you expect to produce pizzas commercially (ie: lots of pizzas baked one after another sort of rapidly). But no one here has tried it so if you decide it is worth the experiment let us know how it works out.

Looks good! I would suggest that you wire wheel (large cup brush on angle grinder) the inside of the dome. My WFO has had no problem with rust flaking down on what's baking inside but if one rubs one's hand on the interior surface one does come way with a red brown colored hand. I wire wheeled the interior (exterior as well, didn't want problems with paint burning off) of the steel dome when I built mine and have had no need to further address internal rust issues. It's a dirty task but IMHO worth doing.

Bests,
Wiley
Reply With Quote
  #15  
Old 10-18-2011, 05:07 PM
Serf
 
Join Date: Aug 2008
Location: Indianapolis
Posts: 19
Default Re: Preparing for steel oven build.

Does the vermicrete border need to be of a refractory cement or will regular quick-crete work? I did pick up 3 bags of refractory, but at $30 a pop I wonder if the job will be done just as well with $5 bags.
Reply With Quote
  #16  
Old 10-18-2011, 11:28 PM
Master Builder
 
Join Date: Mar 2008
Location: Washington State USA
Posts: 777
Default Re: Preparing for steel oven build.

Scarnucci
Where I come from Quikcrete is a mix that when water is added makes concrete. It has gravel and sand and cement.

You do not have to use refractory (calcium aluminate) cement when mixing vermicrete, regular portland type 2 will work just fine. Probably portland type one or even "plastic" cement (which is plastic only in consistancy/flexibility not made of plastic) would probably work as well. There are a couple of good threads concerning how to mix so I would advise checking the archives. RTflorida (if memory serves) had a procedure for mixing and placing which allowed for high insulation with little cement and lots of vermicrete (9 or 10 to 1 vermicrete to cement ratios are possible). The threads are a couple or three years ago.

Hope this helps,
Wiley
Reply With Quote
  #17  
Old 01-09-2012, 02:51 PM
Peasant
 
Join Date: Jan 2012
Location: Oklahoma
Posts: 36
Default Re: Preparing for steel oven build.

Scarnucci,

How did your oven turn out? I have poured my foundation and liked your version for a dome.
Reply With Quote
  #18  
Old 08-06-2013, 06:33 PM
Serf
 
Join Date: Aug 2008
Location: Indianapolis
Posts: 19
Default Re: Preparing for steel oven build.

Pizza fiends,

A cheating wife and a divorce and a topsy turvey 2012 put my build on ice, but never out of mind.

If it is in your heart, in your blood, if it is your passion, you can find a way. So, here I am, keeping the dream alive.

The last photos I showed were the bricks directly on top of the insulation. During one road trip to and from the welder, I had the unpleasant experience of the weight of the dome on some bricks digging trenches into the insulation. Ive attached some photos of the tray I had built to lay the bricks into, and then of course the dome rests on top.

As you can hopefully see, there remains a gap of about the width of a two by four all the way around the tray. I added some brackets to the dome where I have eight inch, 5/8ths bolts and nuts going up through the trailer frame, through the brick frame, through the fire brick, and holding the dome in place. It seems to be fairly sturdy. Ill see how it holds up after a few road trips.
Attached Thumbnails
Preparing for steel oven build.-trailer1.jpg   Preparing for steel oven build.-trailer-2.jpg  
Reply With Quote
  #19  
Old 08-06-2013, 06:39 PM
Serf
 
Join Date: Aug 2008
Location: Indianapolis
Posts: 19
Default Re: Preparing for steel oven build.

The above pictures also show part of the frame for the "hut" that will enclose the dome. During test fires I just had the fire inside an uncovered dome. While the temps on the underside of the trailer remained warm to the touch, the heat pouring out of the un-insulated top was off the charts. I could just see waves and waves of energy escaping into the air. The pizza showed that as well. Even though my bottoms and crust was getting done, the top was never cooking at the same pace, and I had to finish them in my oven's broiler.
Attached Thumbnails
Preparing for steel oven build.-pie1.jpg  
Reply With Quote
  #20  
Old 08-06-2013, 06:50 PM
Serf
 
Join Date: Aug 2008
Location: Indianapolis
Posts: 19
Default Re: Preparing for steel oven build.

Having read another thread about turning a Webber grill into a mini pizza oven, I saw suggestions of welding a steel plate above the pies to reflect the heat back downwards. I decided to have a shelf of angle iron welded inside the dome. The shelf is sized so that I can insert about 5 fire bricks about 12 to 18 inches (I never measured) above the cooking surface. Once the oven has heated, these ceiling bricks are nearly as hot as the floor bricks. As I cook and rotate and finish the bottom of the pie, I can lift the pizza up, and char and cook the top of the pizza with the heat radiating from the ceiling blocks. I trust you can see the difference.

also, I wrapped the dome in Superwool. My goodness that is great stuff. Whereas before the insulating wool, I would have lost a limb attempting to touch the super heated steel dome, the wool insulates the dome wonderfully, and I can touch the wool with no problem. Having seen first hand how much intense heat was lost to the atmosphere before the wool, I am confident that all that heat is now being redirected back into the floor brick layer.

While I did not time my heat up and cool down times last weekend, I did monitor the brick layer at over 800 degrees. I am unconvinced of the necessity of a thermal refractory layer around the dome. I might just go buy another roll of superwool, wrap the hell out of the dome, then close it all off with my metal walled hut. I'll see if the temps hold up during long fires with many pies being cooked before I make up my mind. Good thing is, I can always go back and re-engineer at this point. Just have to remove sides and tweak as necessary.

Input appreciated!
Attached Thumbnails
Preparing for steel oven build.-pie2.jpg   Preparing for steel oven build.-pie3.jpg  
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Why Italian Wood-Fired Ovens are Round james Newbie Forum 50 04-01-2014 09:14 PM
My portable tandoor oven build voon Other Oven Types 6 12-07-2010 10:33 AM
Newbie to build better homes pizza oven BUNDYMARK Australia 16 12-01-2010 01:34 AM
New 40" oven build in Central MN goodnerbaker Introductions 4 09-08-2010 05:28 AM
Why we did the Pompeii Oven james Introductions 0 03-21-2005 03:48 AM


All times are GMT -7. The time now is 08:14 AM.

Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
2006/10 Forno Bravo, LLC