My UK build is out of the ground!

[Bookemdanno]

Re: My UK build is out of the ground!

You'll still get a fair amount of heat into the outer arch and area through the hot gasses flowing up the chimney and heating all the surrounding brickwork. Don't expect this area to be cool, or anything. You should however notice that when the fire dies, the chimney and arch should cool far quicker than the oven bricks.
Vermiculite bricks, like what are used in woodburners could do, but as with most insulating materials they are usually fragile. Another way is to stuff a gap with stove rope and use a heat proof mastic to seal.

[brickie in oz]

Re: My UK build is out of the ground!

Yeah, I agree Al.
I am thinking of putting a split course of those insulated firebrick in to form the thermal break, then continue the herringbone to the front arch.

Will those insulated firebrick do the job?

Cheers

Allan

I used insulating fire bricks for my heat breaks and they work really gooder.

[vincentvega_uk]

Re: My UK build is out of the ground!

Ok, got my inner arch done.
Couldn't work out the transition cuts on the back of the arch perfectly, (maybe I struggled to grasp it as im using forms rather than a IT), my cuts on the arch seem steeper than some I have seen. But as far as I can see its working out well, im cutting the arch and cutting the dome in also, and I am getting a fairly tidy transition.
I have only got 2 more chains then im over the arch now.
I pulled the dome forms out as I couldn't get the brick that would sit directly on the form in the correct position. The form was preventing the brick from following the true curve of the dome, so the brick would lip quite a bit over the course below. They were a good template for my first few chains, but as the radius tightens I think it would have only got worse if they stayed in!

Any feedback always welcome.

Cheers

Allan

[vincentvega_uk]

Re: My UK build is out of the ground!

Yeah, I agree Al.
I am thinking of putting a split course of those insulated firebrick in to form the thermal break, then continue the herringbone to the front arch.

Will those insulated firebrick do the job?

Cheers

Allan

[brickie in oz]

Re: My UK build is out of the ground!

I think heat transfer would act very similar to water.
If there is continuous contact or it can flow unimpeded without a barrier then it will.

[bobmurphy]

Re: My UK build is out of the ground!

I also wanted to do something for a thermal break. Of course I am not sure if this has any effect at all, but here is what I did. I did basically the same thing between the inner arch and the entry. Just a few cuts with the saw to lessen the surface area of contact. I'm sure it will fill with ashes, but still should help.

[jms]

Re: My UK build is out of the ground!

If I would like to install a fire break in the firebrick floor at the entry to the inner arch, what would I use to make the firebreak itself?

Cheers

Allan

Myself and many others have used a piece of stainless steel box tubing which we packed with leftover Calcium Silicate or Ceramic wool insulation.

[vincentvega_uk]

Re: My UK build is out of the ground!

If I would like to install a fire break in the firebrick floor at the entry to the inner arch, what would I use to make the firebreak itself?

Cheers

Allan

[david s]

Re: My UK build is out of the ground!

Im sure there may be another way to construct a vault to reduce the depth though!

Cheers

Allan

you can cast the entry and make it really shallow.

[vincentvega_uk]

Re: My UK build is out of the ground!

Hi Joe,

Yeah thought a lot about the reach, I knew it was going to be quite deep as I still have a brick and a half arch to build out of firebrick for the vault, then a face brick arch to finish it off. Like you say, similar to yours.
Im sure there may be another way to construct a vault to reduce the depth though!

Cheers

Allan

[Bookemdanno]

Re: My UK build is out of the ground!

The bricky skills are showing through!

As for the slight imperfections in the floor, try a peel or something across it, if it does catch you can dress the whole lot off with one of those masonry grinding discs.
I used an Itool, and then a wooden former for the top 3 or 4 courses, but your idea should work. Not used homebrew but it does seem very claggy and rich.
I'm sure you'll get a great result Allan!

[Gulf]

Re: My UK build is out of the ground!

......

Could I build a brick chimney on top of the vault arch? If I did the chimney itself wouldn't have to be firebrick would it?

And I think I would have to buttress the arch to stop any spread due to the extra weight of a brick chimney.

Anyone have thoughts on this?.......

Allan,
It looks like you are going to have a very long reach to access your oven. I do as well. That will most probably bring on plenty of discussion . I built a full heat break around the oven arch and was concerned about the weight. Knowing that I was going to build a brick chimney, I decided to spread the weight around the outer arch(s).



I still built a facebrick chamber around the firebox (entry) and filled with vcrete for buttressing. Firebrick is not necessary for the entry and chimney. But, I did because I wanted to be able to use the extra deep entry for a fireplace as well.

I lot of over kill, probably .

Joe

[vincentvega_uk]

Re: My UK build is out of the ground!

Thanks Boerwarrior for the advice on the vault. Firebricks it is!

Could I build a brick chimney on top of the vault arch? If I did the chimney itself wouldn't have to be firebrick would it?

And I think I would have to buttress the arch to stop any spread due to the extra weight of a brick chimney.

Anyone have thoughts on this?

Thanks

Allan

[vincentvega_uk]

Re: My UK build is out of the ground!

Thanks again everyone for the recent advice.

Yes, laying bricks is my day job, so building a nice brick stand wasn't a problem for me.
Building the oven dome is still scaring the crap out of me though!
Obviously my job will help, but these ovens are so unusual in terms of shape and materials to building home extensions etc.

Anyway made progress yesterday. I got my cal sil board down on a dry sand/fireclay mix as suggested by David and others. It didn't take much but did even out a slight rock in the board.
I then tiled the firebricks in on the floor in a herringbone bond. Should I be concerned about the slight difference in thickness with some of the brick? There is maybe 2-3mm difference in height here and there which is just how the brick have been manufactured. Will the peel catch?
I then set out the dome and entry arch and made my entry arch form.
I have also made some templates for the dome itself as you can see in the photo. I am planning on using these as a guide until the bricks reach such an angle that they need supporting. Then I am planning to fill in between the templates with sand and compact. I can then finish of the dome.
Does this plan seem fine or am I better making a IT?

I then got the brick on edge round for my first course, then got 3 1/2 chains done. I have found that on the 4th chain I have had to put a couple of 3/4 cuts in to keep some sort of bond. I think I will have to start cutting all the bricks down in the next chains as the radius tightens.
I have left the arch and transition for now, I think it will be better to do this as I go rather than attempting to cut all the arch bricks first.

I have been using the homebrew mix which I found really strange. I found it to be very sticky and clay like.

Here are some photos of my progression:

[Bookemdanno]

Re: My UK build is out of the ground!

Hello Allan!

Nice base!

You'll be best off laying your floor/hearth bricks on a mix of homebrew or sand and fireclay, so that'll sort out any minor imperfections in the calsil. Get a 10mm notched trowel and lay the hearth bricks like floor tiles.

Good luck!
Danno