New 42'' pompeii build in Canberra

[Dan W]

Re: New 42'' pompeii build in Canberra

Here's some pics

[Dan W]

Re: New 42'' pompeii build in Canberra

Was keen to smash a big chunk out, so called in the big guns: Me mate Laurence, the wife holding the baby and lil Apprentice, and a cement mixer to mix a ton of mortar.

Cut the arch bricks and a stack of oven bricks during the week, jigged up an arch form, waited for the fog to clear, tuned into JJJ Hottest 100 of the last 20 years, and pulled out the beers (james squire golden ale this time FYI Dave).

Got the arch done - I was slow - in the time it took Laurence to lay a course it took me that and then some to get each row of arch bricks and locking brick trimmed and happily in place. Being the novice I am, it took me a few goes on most arch brick. That was certainly trickier than I was anticipating. Given the time invested, I hope the sucker stays up now!

Thanks again to Laurence!

[brickie in oz]

Re: New 42'' pompeii build in Canberra

Its the clay, as it dries it shrinks.

[cobblerdave]

Re: New 42'' pompeii build in Canberra

Gudday
The sand in the home brew is the matrix the bit that all the rest sticks too. The Portland cement provides the initial set but is effected by heat over 300C and will eventually break down. But at the same time the lime in the mix will take over and provide the long term and heatproof glue. The limes also fairly flexible and will take the stresses put on it as the oven heats and cools. The clay is there to give the mix better workability it sticks to brick better and allows a bit of squish to placing the brick without losing the bond. It's important as it lets one time bricklayers pull of a hard task. You might put a small squit of did washing liquid to the brew as it also improves the plasticity of the brew.
It's pretty cool and dry down your way it would hurt if you covered your job overnight , cement likes warmth and damp to set correctly
Regards dave

[Dan W]

Re: New 42'' pompeii build in Canberra

A homebrewed pale ale to go with my homebrewed mortar Dave.

Thanks David will try that... you say it will 'reduce' cracking, not eliminate... so I guess the next question is therefore - do a few cracks matter? Is it worth pulling up that course and relaying it? And will reducing the fireclay mean a less heat tolerant mortar?

[cobblerdave]

Re: New 42'' pompeii build in Canberra

Gudday
What brand of beer?

Regards dave

[david s]

Re: New 42'' pompeii build in Canberra

If you halve the clay content it will reduce the cracking. You could also try moistening the bricks prior to laying.

[Dan W]

Re: New 42'' pompeii build in Canberra

Alright you lot, I think I need some tips on my mortar.

So I just laid my first course of bricks on top of the floor using homebrew mortar (1 portland cement, 1 lime, 1 fireclay, 3 sand) and as it dried, it cracked like a plumbers.... see photo.

In the pic you'll see I had a stack of mortar left which I pasted on the outside of the bricks. There seems to be hairline cracks between the odd brick also.

I'll admit to being a complete novice when it comes to bricklaying, so would love some tips.

Other info that may have been a factor: I added sufficient water to get it well mixed and just a little drier than a porridge-like consistency. It was a cool day - maybe 15deg C. The bricks were dry. I was drinking beer...

[david s]

Re: New 42'' pompeii build in Canberra

I think one about half way up the dome is a more useful place.

[Dan W]

Re: New 42'' pompeii build in Canberra

Been a bit delayed with the arrival of a baby daughter, which has been awesome. But the show must go on, so while she was napping, I:

1. pulled up the floor, scraped out sand until the vermicrete started showing through in spots (was still 5mm deep in some spots tho);
2. drilled a weep/thermocouple probe hole;
3. re-laid the floor, and;
4. cut a stack of bricks.

The floor is dead level which I'm pretty happy with. Now to the first course.

Question: was thinking I'd drill a hole in the bottom of a floor brick and bring the thermocouple probe up to within a couple of mm of the surface. Anyone else done this, or can you recommend a better/another place to put another probe (I have two) - thinking one up near the top of the dome.

Currently having a little battle with a supplier on ebay. Bought a thermometer and two probes advertised as being rated to 1200degC. However when they arrived the packaging for the probe said it's only rated to 400degC. Brought this up with the seller, and they replied 'nah, the packet's probably wrong - just test it out and we'll refund you'. Their grasp of english (despite being located only one suburb away) couldn't comprehend that it would not be an easy thing to replace once built in if faulty. What sort of temps are regular in these ovens? I presume it's over 400degC quite regularly - but much more than that? might just take a chance.

[Dan W]

Re: New 42'' pompeii build in Canberra

Thanks Al and David. Will get onto that.

[david s]

Re: New 42'' pompeii build in Canberra

The more sand you have the more it will move under the bricks,

that's why the usual brew is sand, clay and water. It sets up hard and can not move. Your layer of sand should work fine though and I'm sure it won't give you any problems.

[brickie in oz]

Re: New 42'' pompeii build in Canberra

The more sand you have the more it will move under the bricks, you really only need to level out the bumps with the sand.

[Dan W]

Re: New 42'' pompeii build in Canberra

[QUOTE=brickie in oz;151327]Thats a lot of sand, I thought it had to be 1mm or so thick? [/QUOTE

Thanks for that Al. Not too late to pull up the floor and scrape off some sand. What's the rationale behind a thin layer? Is it so the floor bricks don't compress the sand over time and become uneven? My vermicrete base has bumps bigger than 1mm tho! I'd need a little bit more than that I reckon.

So hivemind: what the max amount of sand you'd tolerate?

(ps. this forum rocks!)

[brickie in oz]

Re: New 42'' pompeii build in Canberra

Thats a lot of sand, I thought it had to be 1mm or so thick?