[TheForge] A challenge to Harry

[IowaHarry]

Mikey,

    One of the aricles I have seen in reference to ITC was how it 
protected the ceramic blanket from borax. I intend to put a piece of 
kiln shelf on the bottom so that takes the brunt of the banging around 
in there but the occasional twitch could cause borax to land in the 
wrong spot. For fuel efficiency and borax resistance, these are the main 
reasons I chose to go this route. I only do this as a hobby so, being a 
practicing tightwad I am trying to do it on the cheap.

Harry

Kathy wrote:
> Harry,
> ITC #100 is an infrared reflector (actually a re-radiator) the only protection
> it provides ceramic blanket is in cutting down the amount of conducted heat
> energy into the blanket's interior from its hot-face side; this protection is
> real, but is limited. Over time, the blanket will still overheat and shrink; to
> understand this, look up both the dropping insulation values over an extended
> heating cycle, and the percentage of shrinkage expected as the heating cycles
> are repeated.  The first thing this shrinkage leads to is spalling of areas on
> the hot-face surface, because the ITC #100 coated area is unable to shrink along
> with the rest of the ceramic blanket; instead, it temporarily expands somewhat
> from the great heat it is generating. If you are looking for a protective
> coating, rather than an IR reflector, you would probably be much better served
> by Plistex from Larry Zoeller. He showed me an treated sample at the ABANA
> conference in Kentucky. It was pretty impressive.
>
> Bubble alumina is expensive; far more expensive than Kastolite 3000. Nor do I
> believe it is more insulative than the Kastolite refractory. It is, however good
> for another 1000 degrees temperature increase over K 3000. How frequently you
> have to do repairs on any ceramic blanket depends on how high a temperature is
> reached in the forge/furnace; If you turn one of my tube burners up sufficiently
> to create a white hot interior, you can count on doing repairs to the facing as
> soon as the equipment cools down >:-)
>
> Is it necessary to do so, even for casting? NO, but it is quite a temptation for
> some of us (voice of experience here). 
> Mikey
>
>
>
> -----Original Message-----
> Mikey,
>
>     How do they compare dollar for dollar? I presume kastolite 3000 is a
> castable refractory, but I haven't heard of bubble alumina. I thought the whole
> idea of the ITC  100 was to protect the ceramic blanket for more durability. And
> by frequent, how frequent?
>
> Harry
>
> Kathy wrote:
>   
>> Harry,
>> If you plan on making a good forge/furnace it would be a much better 
>> idea to use Kastolite 3000 refractory or bubble alumina instead of 
>> ceramic blanket. I do strongly urge you to reconsider your insulating 
>> refractory choice, unless you don't mind replacing the ceramic blanket on a
>>     
> frequent basis.
>   
>> Mikey
>>     
>
>
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