Fnbrokens Corner WFO in Canberra, Australia

[david s]

I've only just picked up on your thread. Have you been to your local council about your build? Our council require anything to be built 1.5 m inside any boundary fence. You wouldn't want a complaining neighbour to force you to move it all once it's built.

[fnbroken]

Hi David, Thanks for checking! I [fortunately] don't have any neighbors over the back - its a grass reserve then a main road through the suburb. I also don't have an easement along there either, so i'm pretty safe.

To be sure no one notices over the 1.9m high fence, I also have a hedge of pittosporums growing on the other side of the fence to keep nosey eyes out - at the rate im going they will be fully grown by the time the oven is ready to go. The fence height is also a bit deceiving as well as my yard has been built up by about 400mm on my side - so there is quite a drop on the other side.

I cut and placed the rebar/mesh today. Will weld it in tomorrow....

[fnbroken]

welded in - wont win any awards for being pretty, but it is strong as....

[JRPizza]

I was going to weld mine but the neighbor was helping me with my slab came over and wire tied it up in the time it would have taken me to set up my welder
That mig will come in handy when you build your door!

[fnbroken]

I needed to get it out for a couple other jobs, so made sense to line them all up at the same time. Once i put pergola posts off the top of the slabs i wanted to be sure there would be no movement - better safe than sorry (and probably over-engineered to the max!!). Once i get some of the timber formwork in I will probably weld some more steel in to be sure.

Not sure I will weld the door myself - would probably end up blowing too many ventilation holes in it, lol

[Gulf]

welded in - wont win any awards for being pretty, but it is strong as....

Greg,

I've seen several builds on this forum where folks welded their rebar. I'm pretty sure that it is ok for our purposes with building a wood fired oven. Ovens are small projects. However, just for the record, tying steel is the preferred method. Concrete rebar is a soft steel. Soft steel and concrete have about the same expansion rate at ambient seasonal temperatures ranges. Super heating soft steel changes those properties. I was taught to always tie steel and never thought about any other way. Bending steel was also always done cold with a rod bender. I once saw several tons of steel scrapped on a project. The contractors were lapping and tying the steel to code but, were heating and bending the steel at the corners. The engineer on the project ordered it all to be scrapped.

[JRPizza]

Not sure I will weld the door myself - would probably end up blowing too many ventilation holes in it, lol

Are you using gas or flux core? I was using gas and 0.030" solid wire, and was also worried about blowing holes so I did a series of tacks to hold the door together. Later when I figured out what I was doing I was able to do longer welds on similar gauge material without burning through.

[fnbroken]

Hi Gulf - thanks for the heads up - just spent the last couple hours researching weld/tie rebar! I thought it would be fine given the mesh itself is welded.

So what I learnt (being an armchair specialist welder now) - Low quality rebar can become brittle at the welded spot due to the heat stress and subsequently form the starting point of a crack. After talking with the supplier where I sourced the rebar...Australian rebar standard is reasonably high and not as susceptible to becoming brittle as it has a much lower carbon content. Much like the welded mesh - if the welds are small (more tack welds) there wont be a problem - which mine resemble. Additionally, (to answer JRPizza question) I am using a flux core wire (no gas) so the temperature reached is much lower than using a gas shielded wire. He suggested if I was worried that I should use tie wire on the key structural joins (uprights to the horizontal mesh) to assist in ensuring no movement as any weld is only likely to make part of the rebar brittle - not the whole thing.

So a note to future builders - tie the rebar together!

JRPizza - I will definately give it a go...that's what this project is all about!

[JRPizza]

Greg, I'm still learning the nuances of welding, but I've read that flux core generally runs hotter, gets deeper penetration, and is harder to use on sheet metal than gas, at least if you are using a C25 mix. That said if you practice on some representative material you can figure out what size tacks/stitches/beads will work for the set up you have. Not sure if you saw the way I tacked mine together or not - I attached a link to some pic's below.

[fnbroken]

Thanks JR - not much I can do now - only hope!

I have bookmarked a number of door builds (including yours) and will study up when the time comes....

[fnbroken]

A little more progress this week - hard yakka when temps are in the high 30's!

Cores filled and wood racks bolted to the floor. Its half the price to buy firewood in summer, so will be stocking up now ready for whenever I complete this thing.

Formwork for the doorway is next....

[fnbroken]

One step closer today.... formwork for the door arch in... ready for concrete on Friday!

[fnbroken]

and concrete....

20 barrow loads...fortunately I have a cement mixer :/

[fnbroken]

Pulled the form work off today - pretty happy with the result. Some work with the grinder will fix up the edges, plus I want to round off the corners so they are not so sharp (I banged my head twice removing the forms and it HURT!). I am debating drilling a drainage hole in the middle of the slab (and thru the steel condeck) ... thoughts?

Also got the forms and steel in for the outdoor kitchen.

Time to place an order for the oven materials - super excited to get to this point

[shanesmith80]

Looking great Greg,
I was getting the form work ready yesterday for the suspended slab and was thinking off trying too incorporate an arch like yours, but thought, too much work. But now seeing yours Hmmm.. just maybe i'll give it a go.