Used Pottery Kiln Bricks???

[Mitchamus]

Hi guys,

Just wondering if it is safe to use firebricks that used to be part of a potters Kiln?

I know that some of the heavy metals used in the glazes are toxic?

what would be your thoughts on using them for a pizza oven?

obviously not for the floor - but do you think they might be safe to use in the dome?

cheers,
mitch.

[david s]

Re: Used Pottery Kiln Bricks???

If they are insulating firebricks then they are not what you want. If they are dense firebricks and have been used in a kiln doing only stoneware firings then I'd be using them.

[Mitchamus]

Re: Used Pottery Kiln Bricks???

There are both types.
I think I'm a bit worried about heavy metals from the glazes leeching out.

the kiln is old, and there is no way to know what exactly has been fired in it...

some pics...

[david s]

Re: Used Pottery Kiln Bricks???

If it is lead you are worrying about, then lead frits for eathenware glazes have not been used for decades. Another extensively used heavy metal, iron (browns and greens) is safe as is cobalt (blues), and copper (greens and reds) all used in glass ware and ceramics for centuries. Can't think of too many other heavy metals that could be a problem. The temps we fire to are nowhere near the reactive temps the glazes are likely to produce problems, however you never really know what the bricks history is if they're used ones.

[Johnny the oven man]

Re: Used Pottery Kiln Bricks???

I would be careful, if you dont know the full history of them shy away. For $3 for new bricks,it aint worth it

[david s]

Re: Used Pottery Kiln Bricks???

Did you notice the steel bracing on the outside to hold the expanding bricks in place. This is typical in kiln builds. Usually the threaded rods/nuts can be used to adjust the tension required.At the high temps the kilns reach the expansion in considerable. If you think a wood fired oven is exciting to fire you should experience a kiln being fired to stoneware temps (1200 C plus)- Pyromania- it's great!
I'm currently building a small downdraft stoneware (1200 C plus) kiln using my WFO dome mould for the top. It's going well and will post some pics when I'm a bit futher down the track.

[Johnny the oven man]

Re: Used Pottery Kiln Bricks???

Did you notice the steel bracing on the outside to hold the expanding bricks in place. This is typical in kiln builds. Usually the threaded rods/nuts can be used to adjust the tension required.At the high temps the kilns reach the expansion in considerable. If you think a wood fired oven is exciting to fire you should experience a kiln being fired to stoneware temps (1200 C plus)- Pyromania- it's great!
I'm currently building a small downdraft stoneware (1200 C plus) kiln using my WFO dome mould for the top. It's going well and will post some pics when I'm a bit futher down the track.

The steel bracing is only holding the basic shape together, there is no mortar between the bricks!!!!!!!

[david s]

Re: Used Pottery Kiln Bricks???

The steel bracing is only holding the basic shape together, there is no mortar between the bricks!!!!!!!

Yes, sometimes kilns are built without mortar, particularly if they are temporary.