Drake's 38" Oven

[DrakeRemoray]

Good idea on the aluminum foil and the plastic....

I am building a 20" high dome. More of the Tuscan design...

Drake

[arevalo53anos]

Drake:

I realize that I could attach some pictures that I taked in the vanes phase.

Luis

[mrpbjnance]

Drake - What is the size of the oven you built. It looks HUGE. Or is that just the perspective from the picture?

[DrakeRemoray]

Originally Posted by mrpbjnance

Drake - What is the size of the oven you built. It looks HUGE. Or is that just the perspective from the picture?

It is a 38" oven. It looks huge to me too... but the interior is not that large.

Drake

[Marcel]

Originally Posted by DrakeRemoray

It is a 38" oven. It looks huge to me too... but the interior is not that large.

Drake

(M) "Although the moon is smaller than the Earth, it is farther away!"

(M) Astronomy is my specialty.

Ciao,

Marcel

[DrakeRemoray]

Hi All,

I chose to cast a lintel instead of using an angle iron. I chose to do this mostly because I am planning on casting a vent, so I had the material.

These three pictures show the empty forms, the filled forms and a closeup of the filled forms.

I used "Insulcast", a castable insulating refractory concrete from a company called pryor giggey. It looked a lot like the perlcrete, but it is supposed to be strong structurally up to 1800 deg f.

I have to let these cure (and cure them by baking at increasingly hot tempratures for a couple of hours according to the instructions...), the I will put them in place.

Drake

[Marcel]

(M) If you didn't add re-bar to your lentil soup you may not be getting enough iron.

(M) If you didn't add re-bar to your Lintel form, you may not be getting enough strength.

Ciao,

Marcel

[christo]

i'm a little curious about the rebar in the lentils. Long time ago I worked with industrial boilers and mostly insulation type refractory cements. So I do not claim to know what I am talking about in this instance.

Rebar has a different coefficient of expansion than most masonries.

I'd have to wonder how many heat cycles it would take to break the lentils apart. That may be why Marcel put only a single piece of relatively small diameter rebar in his cast. That way the overall strength of the casting was superior to the force the rebar could exert???

Here's where I need to ask the collective wisdom of the list - Does the chimney throat get all that hot? Does it exceed 600 degrees - i.e. does the soot burn away during firing? I like the casting ideas that are going on here - I want to make sure they are a lasting solution.

also might get away with very small diameter wire in place of rebar to avoid any thermal expansion differences.

Drake and MArcel - nice looking stuff!!!

Christo

[Marcel]

[QUOTE=christo]i'm a little curious about the rebar in the lentils. <snip>

Rebar has a different coefficient of expansion than most masonries.

(M) That's likely to be correct, but steel may need to get a lot hotter than 700F before it expands enough to crak a casting.

I'd have to wonder how many heat cycles it would take to break the lentils apart.

(M) Maybe I was wrong in suggesting re-bar, but another builder put some in his vent manifold.

That may be why Marcel put only a single piece of relatively small diameter rebar in his cast.

(M) You must be confusing me with another builder. I made no cast.

That way the overall strength of the casting was superior to the force the rebar could exert???

(M) I doubt that. If freezing water can crack stone, then steel expanding can crack masonry. But perhaps the masonry expands more than the re-bar? Then you should have an air space around the re-bar inside the brick. Who said "A little knowledge is a dangerous thing" ? Let's get Luis, or other thermal engineers to clarify the effect of heat on rebar inside a masonry casting.

(M) I believe that steel starts to glow only around 2,200 F. and probably doesn't start to measurably expand before then. Though our ovens get hot, they don't get nearly that hot. Anyway, I'm through guessing, but I havent heard anyone complain of re-bar cracking a casting.

Ciao,

Marcel

[DrakeRemoray]

I did add 1 peice of small diameter rebar with each lintel. I painted it first per the instructions on the concrete...You can see it in picture 1 above...


Drake