cast in place with home-brew ??

[robertjusher]

HI All
can the standard home brew , sand, cement, lime and fireclay mix be used for a cast in place dome.
I priced refractroy by the bag and nearly fell over when I worked out how many bags I will need?
Has anyone done a cast oven with home-brew refractoy mix?

Thanks
Rob

[robertjusher]

Re: cast in place with home-brew ??

HI and thanks for the reply. I have seen that thread but it kinda old and I tried to PM the guy a while back,,, must not come here to often.
I am thinking of going similar but no welded rebar. Maybe ss needles or similar if I can find them.
Just seeing if anyone else has tried the method..
Thanks
ROb

[Johnny the oven man]

Re: cast in place with home-brew ??

Try TOTAL REFRACTORY MANAGEMENT for your s/s needles, or I can send some from Melbourne.

[robertjusher]

Re: cast in place with home-brew ??

HI
I spoke with a very helpful guy from total refractory management today. Got some good advice but I was warned off going with a fireclay based homebrew.
He was I guess trying to sell me premix stuff at $40 a bag and at 25kg a lot of bags would be required..
Be cheaper to go firebrick , Bunnings kit or go back to plan A and have a go at a homebrew mortar and hope for the best.
The more I read and talk to people the more confusing this is...
Any thoughts?
ROb

[brickie in oz]

Re: cast in place with home-brew ??

The portland cement you will use in your home brew will last about 5 minutes with a full on pizza temperature fire on its face, I hope you like grit in ya pizza.

There is a reason they sell refractory concrete at the price they do.

[robertjusher]

Re: cast in place with home-brew ??

OK I was unaware the cement would fail if part of the mix.
This is getting deeper then I first thought, So much odd (bad) advice freely available out there...
Really wanted to avoid brick work but really looks like the best way to go, or just build that kit from bunnings.
More thought and reading required.
I have time the weather has put a stop to getting my stand rendered for a bit longer...
Rob

[david s]

Re: cast in place with home-brew ??

Don't be too put off, this method works. The Portland in the homebrew may fail where it receives intense heat on the inside, but that's where the lime takes over. Lots of builders have used the homebrew as mortar and I don't think anyone has reported that it has failed and bits have fallen out. As you are using the same brew you should be OK. But, there is no telling how long it will last. My guess is that it will be quite OK for at least 5 years maybe more.The homebrew is not as strong as a calcium aluminate castable.

[brickie in oz]

Re: cast in place with home-brew ??

Build it with home brew and report back.

[brickie in oz]

Re: cast in place with home-brew ??

Lots of builders have used the homebrew as mortar and I don't think anyone has reported that it has failed and bits have fallen out.

But you are talking thin joints of 5mm or less, thats a bit different to the whole dome being home brew dont you think?

[david s]

Re: cast in place with home-brew ??

But you are talking thin joints of 5mm or less, thats a bit different to the whole dome being home brew dont you think?

Yes it is, but it works. I advised a guy to try this method (unreinforced) two years ago and his oven is still working well. I don't know that he uses it all that often, but it does work. The biggest problem is eliminating the water and the risk of blowing, that's why it is important to add fibres that can burn out.

[robertjusher]

Re: cast in place with home-brew ??

HI
All very interesting, A lot of people in the "it will work camp" and enough people still unsure. I expext to use my oven a lot, so I want it to last more then a few years.
It is going to be a lot cheaper to do an entire home brew dome but if I have to rebuild it every few years ???
I am interested to find out how many pure clay/sand domes are out there working after many years of hard service.
It was the original wfo for many thousands of years and they worked.
Mine will be in the open but will have insulation and a water resistant render, afire brick base and first course.
I need to get my mind made up soon, I rendered the blockowrk today and hope to start the oven next weekend
ROb

[brickie in oz]

Re: cast in place with home-brew ??

It was the original wfo for many thousands of years and they worked.

And probably rebuilt every year too.

[david s]

Re: cast in place with home-brew ??

When we were in Europe in 2010 we saw lots of really old ovens. I was amazed to see how roughly built many of them were. Often large rocks rather than bricks were used and presumably some kind of clay or lime mortar in between. Because of the inaccesability of many of them I doubt whether they had been rebuilt on a regular basis. I think this is testimony to the dome form which is self supporting.

[brickie in oz]

Re: cast in place with home-brew ??

Often large rocks rather than bricks were used and presumably some kind of clay or lime mortar in between.

But not made entirely of home brew mortar?

[david s]

Re: cast in place with home-brew ??

But not made entirely of home brew mortar?

No.

On a scale of strength from weakest to strongest I think it would be
1. Cob (unfired clay)
2. Lime castable (Homebrew)
3. Unfired calcium aluminate castable
4. Firebrick/ fired (to 1200 C, partially vitrified) calcium aluminate castable

All of them work