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Refractory kast o lite 30


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Im building my first propane forge. I just lined it with 2 one inch layers of ceramic blanket and sprayed it with ins tuff rigidizer. In the morning i plan to coat it with kast o lite 30. After i coat it with the kast o lite will it be ok if i just leave it for around 5 days without heating it up?? I wont have time to do any heat treating until next weekend. Ive read a bunch of stuff but nothing that answers my question. Thanks yall!

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Welcome aboard... I always recommend reading this to get the best out of the forum. It's full of tips like editing your profile to show your location, how to do the best search for topics/information and how to keep the moderators happy.:)  READ THIS FIRST

It won't hurt the Kast-o-lite to let it cure without heating, it cures like concrete, you could put an incandescent light bulb inside to help dry out excess moisture. Some folks recommend wrapping the forge in plastic with a damp towel inside for a day or so. We just let ours cure for several days when the humidity was high before firing.

https://www.iforgeiron.com/topic/56991-curing-kast-o-lite-30/

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I will. It shouldn't get that cold. Our low tonight is around 38. The rest of the week its supposed to be warmer. This stuff is a pain to make stick to the sides and top or my forge tho! I assumed it was gonna be more like portland cement. But its much more coarse. 

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  • 5 weeks later...

Between the kast-o-lite and the Mizzou which is better? I've read up on both, and each seem to have their own pros over the other... One insulates better, while the other is tougher. My problem is the kast-o-lite is out of stock everywhere I search, and I don't need 55lbs. I've sourced 13lbs of Mizzou from Canadian forge and farrier. It's all I need to finish my forge, and I'm thinking about pulling the trigger... Thoughts?

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It's not so much a matter of which is better as it is of what fits your needs. Unless a guy is REALLY hard on their forge interiors Kastolite is more than tough enough and is both insulating and impervious to molten borax welding flux. It's a relatively new refractory on the gas forge scene so you don't see it in farrier supplies and such. 

Mizzou has been in use in propane forges since I don't know when and lives up to it's rep and then some. It just has about the same insulating properties as the same thickness of limestone. One foot thickness = R1. It's an excellent flame face and I've never heard anybody complain about flux dissolving it. 

You can buy small quantities for reasonable from the Iforge store though I don't know about shipping or mailing to Canada.

Were it me I'd pull the trigger and finish the forge, you can try something else on the next one. 

Frosty The Lucky.

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Should mention... My itc100ht came yesterday, I was home but they just left it on the step. Couldn't have been much longer than an hour. I think it may have froze a little. The bottom of the jar had a small crack and a very small amount of brown liquid leaked out. I sealed the crack with duct tape and set it on the lid in a dark closet. It should still be good to use?

Edited by Roudyroddypipper
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  • 4 months later...
On 2/4/2020 at 6:25 PM, Frosty said:

Mizzou has been in use in propane forges since I don't know when and lives up to it's rep and then some. It just has about the same insulating properties as the same thickness of limestone. One foot thickness = R1.

Well Frosty's comment sent me on a hunt that lead me to this site https://www.naturalstoneinstitute.org/stoneprofessionals/technical-bulletins/rvalue/ for the R-value of Limestone. I am going to make a post in resources with more information but here is something I found out. Please note that this is comparing Apples to IPhones in a way because the numbers I have for Mizzou are at 2000 degrees and I don't have that level of info on Limestone. 

The R-Value is an imperial system unit of measurement (ft^2·°F·h/BTU) 

Mizzou Castable Refractory 7.4 btu-in/hr-F-ft^2 at 2000 at degrees 
Limestone 8.74 btu-in/hr-F-ft^2

Kast-O-lite 26 LI Insulating Castable Refractory: 4.0 btu-in/hr-F-ft^2 at 2000 degrees
Kast-O-lite 30 LI Insulating Castable Refractory:4.54 btu-in/hr-F-ft^2 at 2000 degrees
IFB 23 2 Btu-in/ft², hr, °F at 2000 degrees
Kaowool 2.98 BTU-in/hr-ft²-°F at 1800 degrees

 

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My problem is I know Kast-o-lite had an r-value but I had no idea how much. I got what is in reality "Brand X"  Cast Master Propane Furnace that has about an inch of bare Kaowool on it. As people have said in other posts talking about this type of  Propane Furnace there is very little air space between the crucible and Kaowool. That suggested to me I was not going to be able to add Kast-o-lite or Mizzou (what I have on hand) on top of the wool. 
That makes me need to know what an inch of Kast-o-lite will get me vs the wool. Given every photo or video showing this thing post first use looks like the wool wilted (for lack of a better term) at least 1/4". 

That was the reason I when head first down this rabbit hole. 

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Oh yeah, ceramic wool refractory does NOT hold up well in flame contact. Propane is very chemically active, especially at high temperature. 

So, rather than using Kastolite,  Plistex can be applied in much thinner layers and will seal the blanket reasonably well against flame contact.

Unfortunately with so little room in the melter it's not likely you'll be able to protect the blanket from high temps, it's going to have a relatively short life span compared to a forge liner.  If you go with Plistex you want to apply multiple thin coats and dried thoroughly between. Mix it like thin latex paint and remember to butter what you apply it to before applying it.

Frosty The Lucky.

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