Fire brick texture - How smooth??

[jbriggs]

I wanted to get everyones opinion on the texture of your fire bricks and how smooth/rough they are. Looking at the pictures of others builds, the bricks appear to be relativly smooth, crisp, and free from surface porosity. Maybe it is just the distance and lighting, but others bricks do not appear to have the same texture as the brick I just bought.

I went to one supplier and was not at all happy with the bricks they had. They were very rough and had various small pits and minute cracks, which appear to be from shrinkage when firing? I headed to another supplier to check out what they had and theirs were a little smoother, but still not what I was expecting. When I mentioned this to the guy, he said they had some of another style that were a little smoother. Attached is an up close pic of the brick that I bought. My concern is the various small "cracks" on the surface and the minor porosity. Does this look similar to what you used??

I realize that there are different varieties, and they were not able to answer what "duty" brick this was, but at $1.20 a brick i am not sure what to expect. Will the bricks wear down and become smoother due to use, or do a majority of you out there polish the bricks (hearth only?)

Your thoughts?

[david s]

Re: Fire brick texture - How smooth??

All fire bricks will be porous because they have been designed to withstand thermal shock and not to melt at high temperature. That is they are unvitrified. Any little pits or cracks should fill up with wood ash. Some builders sand the surface of their firebrick floors, but this is not really neccessary.

[jbriggs]

Re: Fire brick texture - How smooth??

Had to take the pic again at a lower resolution. It might be a bit too close, as you don't get a full perspective, but you get the idea......

I though of using a brick file/sander, which is probabally the route I will go If I am not happy with the smoothness of the floor. Besides, I am using 12"x12"x2.5" firebrick tiles so they might be a different texture alltogether. My dome will be refractory, so the only place I will really be using standard firebrick is the entry and chimney transition.

[Johnny the oven man]

Re: Fire brick texture - How smooth??

Your brick looks OK. Fire bricks are nearly always dry-pressed, some times they arent really pressed sufficiently or lacking that little bit of water content and appear crumbly. Yours have that appearance but will be fine. Porosity of a brick is measured by first weighing the brick dry, then soaking the brick submerged for a specific period of time and then weighing the wet brick. If it weighs 20% more, that is its porosity figure. Most medium duty firebricks are around this figure.

[jerrycook]

Re: Fire brick texture - How smooth??

I had the same concern. The firebrick that I got was from Muddox and was so pitted that I didn't want to use it. They make their brick using an extrusion process. The ends and sides were a lot smoother than the flat area. I opted to buy tiles from Harbison - Walker. They are a lot smoother, but are made of a different material. The Muddox are fireclay and the Harbison-Walker are more of a ceramic, silica compound. They react differently to the mortar. I think the tiles you have will be fine for your floor, they are not nearly as pitted as the extruded fireclay I used for the dome

[Fairview WFO]

Re: Fire brick texture - How smooth??

Mine were the exact same way. These are dry pressed fireclay so they will not be as smooth as a regular brick, but this gives them better thermal stability. Just pick some good ones and you'll be fine once they get dirty.

[stonejohn]

Re: Fire brick texture - How smooth??

hi J, Also a North Carolina build, did you buy your bricks at one of the adams supply locations. If so they usually stock 2 4x9x2.25 a dry pressed and a wire cut. The dry press is very smooth on the 2.25 edges were the brick touched the form, but rough on top and bottom, and one side has a makers mark like a elongated oval. The wire cuts were less expensive but where not as uniform in size or shape. I've purchased many firebrick for fireplace work,but never gave much thought to the surfaces, until the planning of my brick oven.
Good luck
John

[DrakeRemoray]

Re: Fire brick texture - How smooth??

The picture you linked looks about the same as the bricks I used. I think they will be fine.

Drake