Cracks in kiln floor

[2Relaxed]

Hi all,

My 25-year new kiln (I got it used) came with hairline cracks in the floor. I fired the kiln several times and had no issues and probably should have left the cracks alone. But. The kiln also came with a container of some sort of repair paste. It must have been around the same age as the kiln, because when I decided to use it to repair the cracks it only made things worse.

After I applied it to the cracks, dried and fired the kiln again, the paste bubbled up and detached from the bricks. I was literally able to scrape it off with a trowel. Of course it took parts of the bricks with it and now the cracks I have are no longer just hairlines - they're canyons! That have to be fixed I think.

My supplier doesn't carry kiln repair cement unfortunately, so I'm looking for quick locally-available options. 

The paste that came with the kiln is out of the question of course.

I looked for diy recipes and found some but can't be sure they're any good. Here's one thread with recipes:  http://www.potters.org/subject108752.htm I don't have sodium silicate currently but do have grog and fire clay.

I also read through this thread here: https://community.ceramicartsdaily.org/topic/5448-kiln-cementkiln-mortar/

I could go spend $60 on a container of ITC-100 (thankfully available in a store across the highway) and I do have some fiber around to follow Marcia Selsor's recipe , but are their more economical options?

Can I use something like this instead?  https://www.canadiantire.ca/en/pdp/imperial-hi-temp-stove-furnace-cement-710-ml-0642704p.html  This furnace cement is apparently just kaolin with sodium silicate. Perhaps I could use it on its own or with addition of perlite like  recipe#2 from this link:  https://www.canadianknifemaker.ca/index.php?threads/refractory-cement-recipes.2624/

What do you guys think? 

 

 

 

[neilestrick]

Post pics. They may not be an issue.

[2Relaxed]

Here're some pics. I'd still like to know though what I can use to repair...

 

[2Relaxed]

more pics

[Denice]

Cracks and chip like that are no problem,  my old Skutt's floor looks the same way.   If it bothers you a old shelf placed on it will hide it.   High firing makes the kiln bricks shift around,  your lid will eventually start cracking and it  will have to be replaced.    The cracks in the lid will sprinkle brick crumbs on your glaze ware and ruin them,   I am on my third lid on my Skutt and have never replaced the bottom.   I have had my Skutt for 40 years.      Denice

[neilestrick]

As long as the cracks  don't go all the way through, don't worry about them. If they do go all the way through and it doesn't seem structural sound, put a piece of sheet metal under the floor to support it, and make sure the body band is good and tight. None of the chips are big enough to affect the firing, and mortar won't hold the cracks anyway.

Always put a shelf on the floor, up on 1/2" posts, to protect the floor from glaze drips. And it helps insulate the floor a bit.

[2Relaxed]

OK, I guess I'll leave the floor alone. I always have 2 shelves on 1/2" posts on the bottom, and I already have a piece of sheet metal under it that has the vent attached to it. Shouldn't have bothered to change the good for the better with that old kiln paste....

 

Thank you!