Help with Casa2G90 castable refractory pitting

[ncsmoker]

Upon firing up my oven this past weekend, I noticed that the lip around the oven door had some small pitting. I started digging at one with my finger, and it literally just crumpled away.

I installed the oven in September 2013 and have used it approximately once per week or so. I broke it in as stated in the manual, letting the curing fires run 12-14 hours per day for 5 days straight at recommended temperature. I'm not sure if this is a castable refractory problem or what, but any thoughts as to what is going on would be very helpful.

I called FB, and was told they can send me a patch, but did not really answer my question as to what caused this.

For more information on my build, you can visit my page here:

http://www.fornobravo.com/forum/f6/d...ild-20119.html

[Wiley]

Re: Help with Casa2G90 castable refractory pitting

This is just my first thoughts, but it simply appears to be small areas where entrained air in the casting material got "stuck" and failed to migrate to the top when it was vibrated. Surface tension and other factors cause small bubbles to hang up at the margins where the castable material contacts the mold.

The same thing happens in concrete when it is poured and is why one will often see workers hammering the forms when a concrete pour is made in an attempt to free the bubbles and have them migrate to the top surface. These small bubbles often have a thin shell next to the mold which in time breaks revealing the small cavity (formerly a bubble). Mostly this is cosmetic and not to be too concerned with (at least regarding overall strength of the structure). Most people are unaware that in the case of concrete one deliberately adds air entraining agents to the mix to create very small bubbles which actually improves the strength and other properties of the concrete.

In this case I suspect the small bubbles were entrained during mixing.

Hope this helps,
Wiley

[ncsmoker]

Re: Help with Casa2G90 castable refractory pitting

Thank you Wiley.
Just heard back from the FB rep, who said it was due to improper curing or moisture in the oven, which didn't sound right to me.

They are sending out some sort of a "kit" to repair this. Not sure what the contents are or what it entails, but we will see.