"Red Gum Roarer" Part 2

[Bacterium]

As you may already know - I got to a point with my oven where I had built the basic dome and put a cement caping over it. From there it was cured and I have been having a great time cooking in it (posting some stuff in cooking area shortly). So here is where the story picks up again......flue, insulation and more.

first pic is the flue top to bottom - Its a 7inch stainless steel flue that extends beyond the ridge capping of my pergola. This works great at keeping the smoke well above it all.

next pic is the bottom part of flue as it comes out of the arch.... yep that knuckle head looking bloke is me

[Bacterium]

Re: "Red Gum Roarer" Part 2

The front section (oven mouth) is quite short as I didn't want to lose much of my driveway behind and I wanted to be able to access the front of the oven from inside of my pergola.....which would enable me to use it even on a rainy day. Its basically 2 arches where the innermost one is halved in depth about half way up. This gves me a nice slot to lead up into the flue. Yes I'm not the neatest brickie.....I call it "rustic"

After about 10 cooking fires in this thing I have refined my firing techniques. Intially it was taking me 3 hours to heat soak the dome (soot burning of whole of dome) but now I have it down to 2hours reliably. You guys that mention putting your wood on the rack are spot on. Next pic you can see the mesh grates I use under the wood.

and 3rd photo is what they look like. They come out glowing red hot.....

[Bacterium]

Re: "Red Gum Roarer" Part 2

ok the insulating bit. ...After much reading of posts on here (and as per plans here) the best option seemed to be a thermal blanket and some amount of perlite/vermiculite layer. I put on the cermic fiber blanket (1inch) and then some perlite (local landscape supplier) between 1 and 2 inches.

the perlite it weird....just as everyone says strange to put on and it makes you wonder if it will go hard at all. 1 week later (and keeping the kid away from peeling it off) it has now gone rock hard...while the pictures don't show it the whole dome - all the way down to the brick base is covered with the blanket and vermiculite.

I fired it up over a week later, just to see how it went. It amazing how more efficient the oven is. There were a couple spots where I could feel slight warmth but the rest of the dome was stone cold. The warm spots seem to be where I had trouble getting the perlite on thick.

Some days later I then read a post where james and others say "more is good" (insulation that is). I had some blanket left over (enough to cap the top half of the dome) so I put that on top of the vermiculite making sure it covered the two spots where there was some warmth when I fired it......probably not the ideal way but I'm hoping better than none at all.

I then put another layer of chicken wire over the whole lot with the idea this will tie it all down to the base for when I render over the whole insulated area. The wife has booked Sat. and Sun. night with people coming over so it looks like I won't get to do the render for another week......but I will get bread and pizza going....ok time I posted that in the cooking area.

[nissanneill]

Re: "Red Gum Roarer" Part 2

Bacterium,
I did a little tweeking of your initial posting pics as I couldn't see much detail. Here they are, look better on my screen aftera little photoshop work (30 seconds). Will check them out once up on FB site.
I have posted the details:
http://www.fornobravo.com/forum/f14/...photos-90.html
permalink #6.
Regards.

Neill

[Bacterium]

Re: "Red Gum Roarer" Part 2

thanks Neill....got a bit rushed last night - I overlooked the obvious

[Bacterium]

Re: "Red Gum Roarer" Part 2

The weather held off yesterday so first render (stucco) coat went on. No cracking next morning whereas when I did the mortar cap over the dome bricks it did. Main reason being the plasterers sand is quite different to the brickies sand.

[nissanneill]

Re: "Red Gum Roarer" Part 2

Yeh Damon!
the right materials for the right job. Brickie sand will always crack when used to plaster or render.
Did you all a little (a small cap full, approx 1 tablespoon) of domestic laundry detergent in your mix when you made it? It makes it flow and work a lot better. Used by plasterers and brickies everywhere.
Neill

[Bacterium]

Re: "Red Gum Roarer" Part 2

Yeh Damon!
the right materials for the right job. Brickie sand will always crack when used to plaster or render.
Did you all a little (a small cap full, approx 1 tablespoon) of domestic laundry detergent in your mix when you made it? It makes it flow and work a lot better. Used by plasterers and brickies everywhere.
Neill

ahhh laundry detergent....didn't know that....might give it a try as its a bit tricky to work with.
On building sites I've seen gyprock guys put transmission oil in their mix (for same reason).....or salt to make it go off quicker

last coat tonight, have done the first 2 (scratch & brown)....its all drying nicely....no cracks.

Bolzons (local landscape supplier) have given me a contact of a guy who sells all the different sorts of sealers for render. I want something on last that will stop mould etc. so it keeps it looking all nice.

[nissanneill]

Re: "Red Gum Roarer" Part 2

Damon,
the Gyprock guys simply coat the sides of their buckets with transmission oil (or any oil for that matter), so that they simply crack and tip out the left over hard plaster, NOT to improve the workability of the plasters used. A qick and easy cleanout for their next mix.
When I built my current house back in 75, the brickies bought 20l buckets of a mild liquid detergent which was in reality a surfactant and was used to improve the workability of the mortar. Only last year when I undertook a major renovation, the plasterer was mixing a tablespoon of laundry detergent powder in his base render mix for the same reason when he was hard plastering the feature brick walls and plaster patchups where we removed brick arches and unwanted walls.
Hey, have you bought redgum firewood lately? Thought that I'd buy a bit of nice dry wood for the Pompeii on Sunday, could only fit 70kg in the boot (together with my toolbox and dismantled sacktruck trolley) Aus$258 per ton!!! I haven't bought wood for 10 to 12 years. It is transported 800km from Balranald in the NSW. I used around 1/3 of it so it will cost around $5 to $6 per firing. Not bad for a family and friends fiest.


Neill

[Bacterium]

Re: "Red Gum Roarer" Part 2

Neil

yeah its interesting some of the "tricks of the trade"

I had a bad feeling last night as I tipped my final render coat into the wheelbarrow...oops I forgot the detergent..... In the end I got the final render coat on and covered it all up to beat the very windy/rainy weather last night.

Wow redgum is expensive to buy. I have about 20 redgum sleepers (each 2-3metres long) left from some retaining walls I am replacing with concrete sleepers. They have been sitting for 20yrs and burn very well.
Also my Dad dies wood turning and sources some great timbers......It great to see his cutting outfit working on a full size redgum. He can drop a dead redgum tree and then cut it up into planks, tabletops or whatever......seeing/hearing a 4ft bar chainsaw going flat out is just awesome.

I have often thought when my timber supply is getting low of going into the Adelaide Hills and having a chat with a few of the Orchard guys (Apples, pears etc)..... Jim and other have mentioned how good using "fruit" timbers are......your thoughts....

[david s]

Re: "Red Gum Roarer" Part 2

Hi, I'm up in Nth Qld and use Lychee wood. It is really dense and burns nice and hot. But the best wood is free wood. No way would I want to pay money for wood! I pick up fallen gum tree branches every time I walk the dog. The council guys will otherwise remove them and put them through a gas guzzling chipper, so you do everyone a favour

[Bacterium]

Re: "Red Gum Roarer" Part 2

Hi David - free wood....spot on....

Ok, its been a while since I updated my progress. I did the final render on my dome and then let it cure for over 3 weeks and then did a firing. Overall its been fine except for a crack in the front area (near flue) and one down the back. They are minimumal in thickness (back one is quite long). I can't see the thing falling apart with 3 layers of wire mesh contained (within the various layers) but I do wonder if I should try and seal them? They are not in an area where water can sit as such.
Any ideas?
I've fired it 4 times since the cracks appeared and they seem to have settled down.

The dome insulation has worked well and the outer surface doesn't heat up when oven is fired. During/After firing the outer temperature is whatever the ambient temperature is on the day and doesn't vary from this.

I've got some doors to build and am thinking of sealing the outer dome (render/stucco) with some sort of coating so that it keeps the mould off and keeps it looking good.

...its actually quite a nice sunny day here now....hard to get the right picture tho!

[JoeT62]

Re: "Red Gum Roarer" Part 2

Looks fantastic! What are your plans for the doors?

[Bacterium]

Re: "Red Gum Roarer" Part 2

thanks Joe

I'm deep in the planning stage for extensions of my house and the oven has taken a back seat - as far as finishing the doors.

however my thoughts so far:

the oven door will be something simple yet reasonably insulated - I posted this: http://www.fornobravo.com/forum/f6/o...-not-2149.html

Now the doors for the wood storage and ash box areas (bottom front area). I was thinking maybe doing them in steel with some sort of steel frame behind......open to suggestions though.
The idea would be to keep the critters out of the wood area AND to have the ash box behind doors where the hot coals(once removed from oven) can't hurt anyone - they are 2 seperate area seperated by a sealed brick wall.
Maybe a sheetmetal mate of mine will get me motivated with the right ideas and we could do it over a weekend