New build in Sunny Canberra

[timechanter]

Got distracted from rendering and decided to tile the top and prepare landing for granite.

[timechanter]

Thanks Steady . I like your build, I don't know how I missed Ben's (Melbourne Fire brick) kits when I was researching last year. I would just grab one of Ben's kits with a few optional extras if I had my time again.

Should be tiling the landing on Saturday and Rendering Sunday weather permitting.

[Steady]

You have had a busy month timechanter

[cnegrelli]

Would never have thought about that, but that's now so obvious. Great advice.

[david s]

Question: How do you render the front edge of the flue gallery ? I have continued the chicken wire over the front edge and into gallery. But I feel the wire needs to be pinned to the front edge. Am I on the correct track.

Im not doing a brick fascarde arch.

And herein lies a problem. If you join the outer shell to the front facade of the inner shell there is a problem when the inner shell expands inside the colder outer shell..The result is some crackingwhere the two meet, not severe, but cracking nonetheless. An outer decorative arch connected to the outer shell, with a small gap between it and the inner oven allows free expansion without the cracking problem.

[timechanter]

Question: How do you render the front edge of the flue gallery ? I have continued the chicken wire over the front edge and into gallery. But I feel the wire needs to be pinned to the front edge. Am I on the correct track.

Im not doing a brick fascarde arch.

[timechanter]

Finally a dry day. Got the blanket down and found tiles and granite landing pieces.

[timechanter]

Gallery done. Not too bad for my first attempt. Looks strong enough and Chiny fits well.

[timechanter]

Just built my gallery out of foam board and sand. So excited to be laying blanket tomorrow. I'm thinking of just render if I can get the blanket smooth.

[david s]

If the newspaper is jammed in a crease that you want to fill try a stiff scrubbing brush, failing that a wire brush. The fire will deal with any other bits that are difficult to strip away.

[timechanter]

24hrs are up and with the help of a giant umbrella and a tarp I was able to remove the sand whilst the skys' opened with rain (well for Canberra it opened with rain). As I feared there was a slump at a couple of sections, only one that looked big enough to fill (doesn't appear significant, just unsightly). Out of interest, how do you get the Newspaper out (without using fire)? I want to fill the void but the paper is getting in the way.

I'd like to say those needles are damn annoying in the inner shell. I pull a few out and bent the rest my hands found (the hard way) on themselves. Is there anything I should be doing specifically for them?

The rain stopped me dead preparing the entrance, and I am evaluating the bigger reveal any way. Currently the front flue entrance will be 200mm deep and 520mm wide (interior). The Door width into the Dome is 420mm.

[david s]

You can remove the sand after 24 hrs as calcium aluminate concretes achieve max strength then. While the casting is still damp you can fill any voids with some castable. I find it works best if you sieve out the more coarse aggregate then make it into a peanut butter consistency. It won't work very well if the casting is dry. I find 24 hrs after demoulding is good. 2 cm for the rebate is not much, there are advantages to making it bigger in that working the oven is easier with the extra space, it also gives you more wriggle room for the door.

[timechanter]

Thanks Dave,

I had another piece as a front for the entrance to cement up to that I left out of the previous photo. I missed your message so I didn't put oil on its face, I hope the melamine board will release okay. My finished dome is below. If/When I do it again I will make a template for the dome curve out of something stronger than foam-board (which broke first measurement.

I'm planing on making the gallery slightly larger to create the inside reveal of 2 cm.

When finishing I realised I had left a couple of section rough and it had hardened already. At those points its about 6cm thick, so I'm hoping other than cosmetic issues (which will be invisible once the blanket goes on) it shouldnt have to do anything ?

[david s]

You should cover the sand mould to prevent the surface from drying. Cover its surface with strips of wet newspaper to give your casting a good smooth surface and prevent sand sticking to the inside surface of the casting.
if it were mine, I'd be making another door face 2" higher and 2" wider at each side to trowel against so you create the oven door mouth with a nice flat front face of the correct thickness. You also need to oil its face as a release agent, to prevent the castable bonding to it

[david s]

5% is good. 2" thick is enough to give you required strength, sufficient thermal mass, reasonable heat up time and fuel economy. In hot weather I always use chilled water because calcium aluminate cement goes off very fast. Don't mix up more than half a bag at a time and make sure your barrow is cool. ie not left in the sun.
The castable is quite thixotropic so wiggling it a bit will make it more fluid. When done, cover it for 24 hrs, but it does not have to be damp cured for a week like Portland cement as it achieves its full strength in 24 hrs.