Falling bricks?

[dublintom]

I am about to start my 36" build and i am lucky enough to have tapered bricks that should form my dome easily. I have noticed that most people use the indispensable tool to help form their dome but does this also allow the brick to set for a bit. I am finding it hard to understand why the bricks don't fall as you get higher before you have the chain completed and wedged. I know i can use Styrofoam forms but most do not and i feel it could get in the way. Have been looking at loads of pictures and it seems like the bricks are staying up by magic or really fast drying cement. Nerves before i start?

[Tscarborough]

The way masonry works is thus (simplified to answer your question):

Wet mortar is applied to dry bricks.
The moisture is sucked out of the mortar into the brick.
This facilitates short term adhesion and long term bond strength.


This is why you do not soak your bricks, but in extreme conditions may have to dampen them. It also explains why mortar should not be considered to be concrete. They both contain cement and aggregates, but do not share desired physical properties or application methods.

[Les]

Originally Posted by Tscarborough

This is why you do not soak your bricks, but in extreme conditions may have to dampen them. It also explains why mortar should not be considered to be concrete. They both contain cement and aggregates, but do not share desired physical properties or application methods.

Or you could use hot melt glue

Worked for me...

[Dino_Pizza]

About to start, Dublintom? Good for you and congratulations on beginning you oven. The bricks really do stay put quite easily. On the lower oven rings the bricks are not deifying gravity so they stay put. On the upper rows, you just hold it there for 1-2 minutes, and if you didn't over-soak your bricks (see tscarb's reply above) it sticks, and you can move on. If you are building the oven all by yourself, it helps to have sticks, or pvc pipe, wooden stakes or whatever to hold up a brick while it sets for a few minutes while you move on to the next row.

I feel the work and time of cutting a Styrofoam ball could go into just holding the brick in place for 1 minute or placing a stick to give the brick the 3-5 minute support it needs until it's permanently set. The bricks stick surprisingly well. HOWEVER: it wouldn't be a proper wfo building experience until a few bricks fall just when you turn your back. I have 42" oven and I would say maybe 5 brick fell (near the top) that I had to scrape off the mortar, clean them, and re set them. And this time, hold on to them for a few minutes longer before removed my hand. The arches absolutely need forms (a plywood arch) to keep them from falling unless you cut good wedges with little to no mortar.

good luck on your oven build, Dino

[jmhepworth]

I was surprised that even toward the top the mortar held the bricks after a half minute or so of holding them in place. I just used the string and knot method and it worked fine. I'm envious of the perfect shape of the ovens that use the indispensable tool, but I suspect the pizza doesn't care that very little about my oven is perfectly round, square, plumb or level.

[dublintom]

Thanks for the replies lads. Next thing is to figure out how to upload photos but i reckon that a job for the young lad!
Tom

[Neil2]

The Styrofoam form need not be a solid ball. I made mine "fan shaped" with leaves cut from a sheet of 1/2 in foam.

[LTG]

Originally Posted by dublintom

I am about to start my 36" build and i am lucky enough to have tapered bricks that should form my dome easily. I have noticed that most people use the indispensable tool to help form their dome but does this also allow the brick to set for a bit. ..............

Hello "dublintom"...Greetings from another Dub Tommy "LTG" ...near Cabinteely....just now ready to build 39 Inch Pompeii oven....I have base and concrete plinth completed....laid the vermiculite base of 4 Inches 48 hours ago ( today sat 14th Aug 2010)...now concerned that it's a bit spongy....and concerned about oven weight standing on it !.....used " Dineen exfoliated" vermiculite sized 1 to 15 mm and ratio portland 1:5 vermiculite.

Wondering did you use the same product and how did you get on with the insulating base under the fire hearth.

Would be interested in talking to you over the phone about your experiences to date.

Will worry about the bricks falling later !
Tommy 087-624 2244

[dublintom]

Hi LTG
Well done on starting. I wouldn't worry about the base being spongy, give it a week and it will be fine. I used a mixture of medium and coarse vermiculite at 7:1, went away for 3 weeks and it was fine. I laid out the base last Sunday week and i put in the keystone at the top of the dome tonight so I am celebrating. Guess I was lucky with the weather, not having rain for a week. I have loads of pictures but havn't had time to put them up yet. I am actually from your area ie Sallynoggin but am living in Drogheda now. I have a lot of bricks over which are tapered and you are welcome to them. Best of luck with the build.
Tom
Ps only one brick fell!

[leckig]

Tom, congrats! It took me two months what you did in a week Did you use any support for the last 2-3 chains?