Fire Brick Size?

[Derkp]

Hi,

We have quite a few fire brick that are 2.5-7"X5X18 long, also our design is almost all exact dry fit.

How much mortar is required if the bricks fit tight?

Anything that I should know about using such large bricks in the hearth and back wall?

Thanks
Derk

[Raffy]

Re: Fire Brick Size?

Using large brick is actually good for the hearth. The less seams the better for cooking since the the hearth/floor is the surface where the food will be cooked. If your brick is 5 inches thick then you'll have more thermal mass than most other oven's built with the FB Pompeii Plans. Standard firebrick is around 4 inches thick you see but I don't see any problems with that. Worst consequence is that it will take you a few minutes longer to heat up the floor.

[Derkp]

Re: Fire Brick Size?

Thanks for the help.

I remeasured my brick and it is 4 1/2 inches thick. It is also new firebrick from a scrapped steel factory, they had many, many, many thousands of different sizes. The company selling it said it was good for 3000 degrees F. We are planning on a 27X41 oven floor with a 14 inch arch height. We are designing a barrel oven. Does anything sound funny with those numbers?

Thanks for your advice.

Derk

[Tscarborough]

Re: Fire Brick Size?

With a 14" arch height, your opening will need to be around 8.75 to 9 inches tall. That seems pretty low. My barrel vault is 22"Wx36L" long, with an dome height of 22" and an opening of a tad over 13".

[Derkp]

Re: Fire Brick Size?

I am still in the dry fit, see what size I really want stage.

Thanks for the help.

Are there any other critical measurements that I need to be aware of before I start mixing cement?

I could just add a brick or two to the arch and opening and I could come close to your measurements. Does it draw ok?
I have ordered all of the most popular and recommended books through interlibrary loan to get all the knowledge I can before I start.

I will try to post a few photos this evening of what I have to work with.

Thanks again,

Derk

[Tscarborough]

Re: Fire Brick Size?

One match fire start and not a whiff of smoke out the front.

[Derkp]

Re: Fire Brick Size?

Is the bottom of the flue pipe at the inside height of the dome or the opening?

[Tscarborough]

Re: Fire Brick Size?

[Derkp]

Re: Fire Brick Size?

Thanks !

That is the picture I have been looking for!

Did you use regular mortar to full in the space or Refractory?

[Tscarborough]

Re: Fire Brick Size?

Home brew refractory. Link in sig has all the pics.

[Derkp]

Re: Fire Brick Size?

More great pictures. Thanks

Is this order correct:

Block stand
30X30 slabs--concrete?
Perlite/concrete insulation layer?
Thin layer of mortar to set firebricks
oven floor

I have seen a few designs that have an isulating layer recessed in the top cavity between the blocks, a layer of cement that spans the blocks and then oven floor.

I am about to get serious but I am still looking for fireclay to make my own homebrew. So far $29.00 to ship a $15 dollar bag,50 lbs.

Derk

[Tscarborough]

Re: Fire Brick Size?

Have you googled masonry suppliers for your area?

Yes, I had some old 30x30x2 inch pads I used instead of placing a slab, then 4" of perlcrete, a mortar leveling bed, then the floor.

[Derkp]

Re: Fire Brick Size?

I have found a few ceramic/pottery places I am going to try tomorrow. There seems to be different types of fireclay. Is your percrete pad sturdy? Hold the weight well ? Compress? There seems to be many approaces to slab, insulation, floor percrete combinations.

[Tscarborough]

Re: Fire Brick Size?

Ceramic/pottery places around here charge $9.50 for a firebrick while the masonry supply houses charge a buck fifty for the identical unit.

The compressive strength of 8-1 or even 12-1 is more than adequate for this application. There are many ways to skin the cat, but the purpose is to build a thermal mass, highly insulated.

[Derkp]

Re: Fire Brick Size?

Tom,

What was the recipe for your home-brew fireclay mortar? there seems to be many skinned cat ideas on this also.
I have found fireclay (dry) here in Salt Lake. It is about $16.00 per 55lb but no shipping.

Derk