November 2/06

Here's a photo of a model I made for a heater we are going to build.

concrete panel heater model
The 3/4" birch ply represents 3" thick concrete panels at a scale of 1/4" = 1".
The concrete panels will be made by local concrete counter guys and attached
with pins and splines like soapstone.  The mantle will be steel and will offer some
additonal opportunities for joining the panels.  The wood box is lower left with
eventual wood waiter coming up from the basement.  The chimney will be
Class A stainless coming out of the right side of the heater. 
I made the model becasue I was concerned about getting the panels designed
right for the concrete guys but now that we have it it's a great tool for them while
creating the panels. It guess its what you do if you don't do CAD! It was actually
pretty fun making the model and when I brought it home my 9 month old thought
it was fun to play with. 
Anyway I thought you might find it interesting, this expiremental heater
(at least for me).  I'll send finished photos when it's done sometime in December.


Update: January 17/07

concrete panel heater by William Davenport

hi Norbert-
Here's the finished concrete panel heater- a few changes from the model Ii had made but basically the finished result as of yesterday.  Still needs the cleanouts (round concrete disks) and the firebox door of course.  Also needs the custom steel lid I'll make for the little wood box.
The project went pretty smooth- the guys who made the panels for us did a great job and we didn't have to adjust them at all as we assembled it.  There are fairly rugged splines (1/2 x 1 1/2) steel bar and pins for the head joints from 1/4" round steel pegs welded through 1/4 x 1/2 steel bar.  There's a few "L" brackets inside in a few areas too.  Once assembled the sucker was bombproof.  I wrapped the inside with 1/8" ceramic paper in most areas and 1/4"  ceramic paper around the firebox.  A little bit conservative on the slipjoint/insulation but I don't know quite what to expect yet with the concrete performance wise and so we'll find out. 
We made the mantle in our shop and fastened it between the 3rd and 4th course of panels.  We'll see how that works.  I feel that the large 1/4" steel plate will be big enough to distrubute heat out and cool where it overhangs amply.  We'll see.
Anyhow I'm pretty happy with the job becasue it was somewhat expiremental and the install went well. It took a lot of design work. The cleint is very happy.  Aesthetically people either love it or they hate it.
So now we'll just see how the concrete performs.  We'll break it in slowly and try not to stress it out as it is still curing.
I'll send some good finished pics down the road-
Hope all is well-William