spalling hearth

[KEmerson]

Hello,
Have any of you had to deal with a spalling hearth? I'm tempted to just leave it but what would it require to fix? None of the hearth brick is cemented of course. But how would I get some out? Is it easy to get a new one in? Is it all that necessary to replaced spalled brick?
Thanks
Kim

[Neil2]

Re: spalling hearth

Refractory brick should not spall. Is it just one brick or all of them ?

[Tscarborough]

Re: spalling hearth

Is it actual spalling? That is, are small circular convex chips popping off, or is it simply deteriorating, or is the face of the brick delaminating. A picture is worth a 1000 words, because before you bother replacing, you need to solve the issue that is causing it.

[KEmerson]

Re: spalling hearth

I'll get some pics and post.

[nissanneill]

Re: spalling hearth

kimemerson

But how would I get some out?

It is easier to et them out if you drill a couple of holes in the offending bricks and insert what we call dyna bolts. You can bolt some chain or wire under the nuts and lever them out with a jemmy bar.

Neill

[KEmerson]

Re: spalling hearth

Ok, sorry for the delay. These pics aren't great but I think they show what's happened. I assume moisture had something to do with this. I have made bread in the oven and I have "mopped" the hearth after the coals came out and sprayed/misted as the loaves went in. I know I have to do this at the bread baking temps and not the pizza baking temps so I wonder if I did it too soon. I simply don't remember. Also (not that this is the culprit but I thought I'd pass it along anyway because it could be) for one bake I tried the wood simply was not dry enough, which I discovered after lighting it and trying to keep a good heat going. Eventually the breads were baked but I decided that after I was finished for that day to simply put a ton of logs in the now hot oven and let them stay in there until I was ready for the next bake, figuring it would dry them like a kiln. A couple of weeks later as I was readying another bake, I noted that the logs in the oven had gotten mildewy. Still, I went ahead. I cannot recall if I had this brick issue before or after the removal of the mildew logs. Anyway, the bricks are indeed deteriorating somewhat. Any ideas? Thanks.
Kim

[texassourdough]

Re: spalling hearth

Hi Kim!

The mildew and logs are not the culprits. Using too wet a mop or spraying the hearth could be. If it is under area you have your fire or otherwise not in the area where you bake your pizzas I wouldn't do anything.

The mildew would be an indication that your oven did get wet over the winter. Mine does too. Good idea to heat it up gently with a few increasing fires. In theory a big fire on wet bricks could potentially cause similar damage but I don't expect it.

Look forward to others thoughts!
Jay

[Neil2]

Re: spalling hearth

From what I can see in the pictures, they do not look like refractory bricks.

Mopping the floor with a damp cloth is common and true refractory bricks are not affected.

[KEmerson]

Re: spalling hearth

Well, I bought refractory bricks. Have all the receipts. I even helped load them at the time and I saw the label on the skids they were on. We had very specific conversations about refractory brick when I bought them. I know the color on the photos is not true, so what makes you think they're not refractory? They are all the same as all the other bricks and the inner dome is dong fine. I think.
Kim

[KEmerson]

Re: spalling hearth

Jay,
the damage is fairly distributed on the floor. It is definitely right where I place pizzas and breads.

[KEmerson]

Re: spalling hearth

ok, I'm hitting the post reply button faster than I'm thinking. It's still early and I haven't had the first taste of tea yet...

At this point I think I'd like to know about the difficulty of replacing the bricks. I still have several left over and of course I could likely just flip these bricks, provided they are indeed refractory. I could just go buy new brick and triple check that that's what they are. But how hard is it to replace? What are the risks? Is there a tried and true method? (And I mean tried and true, not guessed and suspected). Naturally, they are not cemented so in theory they should more or less pop out once the first one is out, which I suspect would have to be the sacrificial brick in order to allow the others to come out. (I can't wait to crawl inside and lie down in a dark, used, cramped wood-fired oven. How much fun can one guy have?)

[egalecki]

Re: spalling hearth

I think the easiest way to get one out is as Neil suggested- drill a hole with a masonry bit and put a tapcon screw in (masonry screw, blue in color) and pull it out using the screw as a handle. You can buy them at the local hardware store and they sell the bits right with the screws.

[Wiley]

Re: spalling hearth

Kim,
Sorry to learn of your problem with the bricks. My personal opinion is that Neil's suggestion regarding expansion bolts to lift a sacrificial brick is probably the best. I would also suggest that after drilling and installing the expansion bolts that you spend a few minutes with a shop vac vacuuming out as much of the ash etc from the seams between all the bricks in the floor.

Having a few spare bricks from the batch used in construction of the floor is great. Just like tile for floors or shingles for a composition roof, having identical spares for replacement makes the job easier and the result less noticeable. While in this case there are no cosmetic concerns, any variance in the dimensions of bricks over time (our WFOs are designed for lots of years/decades of use) would certainly be problematic in making repairs. Your idea to simply invert and use the otherside of the bricks will be money saving. However, if I am reading the archives correctly, your WFO came online in October of last year; if it was somehow a problem with the bricks the other side will probably have the same issue. This would mean you might be faced with the same problem again in another six months :-(

Bests,
Wiley

[Neil2]

Re: spalling hearth

Test a brick.

Set one edge on a support and start giving it a few wacks with a sledge. It should not spall, powder or delaminate in any way. When it fails it should be by a clean break all the way through. If the batch you have is the wrong brick then there is no point in replacing the failed bricks with the same.

[KEmerson]

Re: spalling hearth

Neil,
I just did a quick test by simply hitting one of the left over bricks with a regular hammer and in one easy hit it split in two quite cleanly. Does that tell us anything?

Wiley,
I agree that if the bricks are not refractory then the problem will repeat. But if they are refractory then flipping would be ok, wouldn't it?

And if I haven't said so already, thanks.
Kim