dmun's 36" geodesic oven part II

[dmun]

Originally Posted by swripley

I especially like the curved lines of your roof. I am currently grappling with my very simple hip roof design and am stretched to my maximum abilities.

Hip roofs are hard, and the curve is just icing on the cake. The real work is the hip roof it's self. You have to admire the Victorians, who built riots of elaborate rooflines with no more than a framing square and a plumb bob. Can you imagine working without a retractable tape measure, let alone a CAD program?

[CanuckJim]

Dmun,

I haven't said much in response to your magesterial log of the build, but I think I speak for many members here when I say that your long term vision and execution of what you see is truly marvelous. Congratulations.

And, no, living in an 1856 balloon frame house with mortises and tenons everywhere and material dimensions we can only dream about, I cannot understand how those guys did that. I have white pine interior panelling that's 22 inches wide and twenty feet long without a knot in sight; all hand planed. Cripes, makes my arms ache just thinking about it.

There are hip roofs all around me of the same period. They did not have multi-ply, thin wood for the curves, yet they are still standing. Amazing when you think about it.

Just cast your mind back to punching that first, rather tentative, hole in the wall. Well done.

Jim

[jwnorris]

Originally Posted by CanuckJim

<snip> Well done.
Jim

Well done, indeed.

J W

[dmun]

Ok, I've been behind schedule on posting the progress with my oven, so here are a bunch of pictures to keep you informed about the progress of my chimney.



When I was last documenting my masonry work, the oven and the fireplace were both walled up to the tops of the smoke chambers, and the support bridge for the chimney had been poured over the oven. Now I start building the flue and it's surrounding block structure up from the fireplace to get them to the same level.



This part of the chimney goes up through a slot cut in the wallboard.



After some thought, I decided to tilt the fireplace flue eight degrees back, the plan being for the two flues to converge at the required five inches apart at the top of the tower. This required two eight degree cuts on every block level, and there are a lot of them.



The bricky system contains a jig to mortar the ends of four inch blocks. Unfortunatly the flue is in too confined a space to use the big bricky for the horizontal joints.

[dmun]

The refractory flue tiles, particularly the eight by twelve ones, are really heavy and awkward to handle.



Here's a couple of c-clamps pressed into service (with plywood cushons) for use as handles. Remember, you have to drop the down from above, often into a pre-built concrete hole.



In position.



Mortared in, and blocked to the height of the oven bridge.



After the refractory mortar had set for a day, I could use the top of the flue as a work position for the mortar tub. Space is really tight in the tower, and is going to get tighter as I go up.

[dmun]

I decided that the sill plate at the top of the block wall shouldn't be cut, for reasons of the structural stability of the studio.



This means that that it goes through the chimney, and needs two inches of airspace and four inches of masonry between it and the flues. A concrete slug will be formed and poured around the space around the 2x8.



Another construction detail: since the fireplace chimney goes up at an eight degree angle it will get unstable after a while (remember, the flue tiles are supposed to be free-standing). Here is a block of insblock19 used as a slip plane for the flue to lean on. I used three of these in the length of the run. Here, the lower flue tile is mortared, and ready for the placement of the next tile. See that shiny stuff at the bottom of the flue? I put a layer of bubble wrap over the damper, so falling mortar wouldn't glue my damper shut.



Onward,



and upward. Ready for the chimney block run, you can see one at my feet.

[dmun]

Those chimney blocks were heavy. There was no way for one person to carry them up a ladder, and no room for two.



Here's a winch, improvised from a big winding barrel from my tower clock. There's a pulley mounted at the top of the tower, and another one on the clamp jig, to compound it once. A direct lift was possible with the flue tile shown here, but not the chimney block.



Here's a chimney block on the way up. Every other block got one side cut off, to avoid a running seam going up the chimney, so there were only three full blocks to lift. Three were enough. Even the cut ones were super-heavy.



Swinging sideways into position.

[dmun]

Moving upward:



A chimney block in position



Another insblock19 slip plane.



As I got higher, I built a platform to work on. Notice the household storage bowl at my feet. I ran out of space for the mortar tub, and after it tipped off a precarious perch, i switched to that bowl to carry up the mortar.



I eventually put a step stool on top of that. In August, window or no window, it was a sweat box in the tower. The air conditioning didn't flow up, of course, and lugging stuff up the ladder into the heat made this one particularly unpleasant job.

[dmun]

At the tower ceiling,



The flues converge.



I couldn't climb the ladder that high, there wasn't room. I had to climb the scaffold and then scoot sideways to get onto the ladder.



At the top. From here on, it's building from the outside.

[jwnorris]

Impressive, to say the least.

J W