Go Back   Forno Bravo Forum: The Wood-Fired Oven Community > Pizza Oven Design and Installation > Pompeii Oven Construction

Like Tree2Likes

Reply
 
LinkBack Thread Tools Display Modes
  #51  
Old 10-07-2006, 05:05 PM
dmun's Avatar
Moderator
 
Join Date: Jul 2005
Location: New Jersey USA
Posts: 4,216
Default firebox instalation



Here's the template on the insulating concrete base of the fireplace. I've chalked around it to show where to put mortar.



Here's the floor laid in, with the extra bricks around it to support the walls. I used sacrete type S (the same mortar I've used for the structural brick and block work) to stick it to the floor, and firestop 50 between the firebricks. That left me juggling two batches of mortar, and two trowels.



This is the firebox half way up: The visible part of the fireplace is seven bricks high.
Reply With Quote
  #52  
Old 10-07-2006, 05:09 PM
dmun's Avatar
Moderator
 
Join Date: Jul 2005
Location: New Jersey USA
Posts: 4,216
Default firebox instalation

Here is the firebox all the way up, plus two partial rows for the back of the Rumford throat.



A side view. Note in all these pictures a rare use of my Great Grandfather Straw's plumb bob.



Scrubbed and ready for the rest of the throat construction.

Reply With Quote
  #53  
Old 10-07-2006, 05:30 PM
CAM's Avatar
CAM CAM is offline
Peasant
 
Join Date: Jul 2006
Location: Stuart FL
Posts: 39
Default Wow

Quite the project you've got going and very nice work. Can't wait to see more. Please keep the pictures coming. Very cool!
Reply With Quote
  #54  
Old 10-15-2006, 04:02 PM
dmun's Avatar
Moderator
 
Join Date: Jul 2005
Location: New Jersey USA
Posts: 4,216
Default rumford throat

Here's the drawing for the rumford "throat".

A word of explaination: Rumford realized that all the heat from a fireplace came from radiation, rather than heating the air. His plan was to make a shallow firebox with steeply angled walls, topped with a inverted funnel with a flat back to match the vertical back wall of the firebox, and a curved front surface to channel the smoke into a narrow slot at the top. This creates a jet effect that fully burns the wood, rather than have the smoky mess that too many modern domestic fireplaces are.

The rectangle in the drawing represents the two pieces of plywood that guide the curve of the throat in the jig, like the ribs of an oven jig. This photo shows the form mounted and in position. I had to make a rim at the front of the form to support the first row of bricks.

Here are the brick wedges you see in side view in the drawing. By coincidence the angle of the strips is the same as my jig I made for the geodesic triangles. Each strip is formed by cutting an angled piece off each edge of a firebrick, and then cutting it in half.
Reply With Quote
  #55  
Old 10-15-2006, 04:10 PM
dmun's Avatar
Moderator
 
Join Date: Jul 2005
Location: New Jersey USA
Posts: 4,216
Default Rumford throat

The side walls of the inverted funnel have wierd angled curves. These were drawn to a cardboard jig, and pretty much cut by hand.

The first rows of bricks were half bricks, cut at an angle to be vertical in the front. The curve of the throat was then established by the angled strips. It's a little odd from the brick oven perspective, because the curve is concave, and the wide part of the brick faces inward.

Halfway up, an unwanted angle is appearing, because of the cumulative errors of the hand cut strips.

a (blurry) inside view.

Last edited by dmun; 10-15-2006 at 08:50 PM.
Reply With Quote
  #56  
Old 10-15-2006, 04:15 PM
dmun's Avatar
Moderator
 
Join Date: Jul 2005
Location: New Jersey USA
Posts: 4,216
Default Rumford throat

I compensated for the unwanted angle with the last row of bricks, which I cut to fit.

It doesn't look to sleek on the outside, but this will all be buried in concrete.

Speaking of buried in concrete: The back of the firebox will be insulated with pearlite concrete. I built angled forms to reduce the amount needed, it still took almost two full big bags of pearlite to do this. Partway full:
Reply With Quote
  #57  
Old 10-15-2006, 04:19 PM
dmun's Avatar
Moderator
 
Join Date: Jul 2005
Location: New Jersey USA
Posts: 4,216
Default Slab forms

I built the forms for the slab on the outside, using a shipping skid which happily could be modified to fit.





As you can tell, I don't think things that are going directly into the dumpster or kindling box shoud be built any better than necessary.
Reply With Quote
  #58  
Old 10-15-2006, 04:39 PM
maver's Avatar
Master Builder
 
Join Date: Aug 2006
Location: Puyallup, WA
Posts: 571
Default Rumford support

Fantastic work on the Rumford. How did you come up with the plan for the Rumford jig? Yours are the first pictures of construction of a Rumford that I have seen. I was (and probably still will) planning on making the BIA rumford for an exterior fireplace:

http://www.rumford.com/BIARumfordFireplace.pdf

Is there other support under the lowest bricks for the throat (a piece of angle iron) besides the form or will mortar and offset seams support it once mortar is dried?

Really neat Dmum, thanks again for posting.
Reply With Quote
  #59  
Old 10-15-2006, 08:43 PM
dmun's Avatar
Moderator
 
Join Date: Jul 2005
Location: New Jersey USA
Posts: 4,216
Default

I looked at the plans for the BIA rumford. I would suggest following the rumford.com plans instead:

http://www.rumford.com/classicflyerplan.html

I took all my dimensions, including the angles and radii, directly from this flyer.

The BIA plan gets one thing right: The flat back. Some adaptations have a sloped backwards fireback because masons were uncomfortable building such a shallow fireplace. Everything else is suspect: The walls are not angled enough, perhaps to accomodate a standard gas log. They don't use the rumford curved throat, terminating in the narrow slot. This reduces emissions, and more thorough cumbustion means less chimney creasote buildup problems.

You don't have to build the throat: Superior clay makes a really good refractory throat for a few hundred dollars, and sells matching dampers, which you probably don't need in an outside fireplace. I am just showing off/being cheap building my own throat.
Reply With Quote
  #60  
Old 10-17-2006, 08:03 AM
jengineer's Avatar
Master Builder
 
Join Date: Aug 2005
Location: Garden-A, South California
Posts: 572
Default Master Craftsman?

I don't know about the rest of you but I think this thread needs to be hit with a sticky or a new subfolder needs to made for the ramblings of DMUN so that they are easy to find and reference.

I am really enjoying this tangent on the building of dual project. It is amazing what a bit of AR, pushing the envelope, perfectionism along with some tools and patience can achieve.
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



All times are GMT -7. The time now is 03:45 AM.

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