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I Forge Iron

Insulation question.


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I am building my forge here at home and am planning on useing a 5 gallon bucket for the body. And I have a couple of questions.

1) Is there a best brand of ceramic insulation? Like, will Kaowl wool give me the best results on forge tempature? Or are they all pretty much the same?

2) I think I understand the refractory cement a little bit. You put it on top of the ceramic fiber to help keep it from getting burnt up by the burners. But, does it also kind of act like a glue? If I am planning on putting two layers of one inch thick ceramic fiber in my forge, do I need to put the refractory cement on the very bottom, then between the two layers, and finally a third coating on the layer that will be exposed?

3) If refractory cement isn't the glue, then what do you use to keep the wool in place?

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1 I think the *BEST* would probably be something like the space shuttle tile material; do you mind if it costs in the thousands of dollars to get the *BEST* instead of 20-50 dollars for very good?  Thousands of smiths, both amateur and professional, use kaowool in their forges.

2  The coating only needs to be applied to the surface exposed inside the forge.

3.  My propane forges are made from cylindrical pipe. The kaowool layers are entire length around and use the arch form to stay in place---it was good enough for the Romans, it is good enough for me.

Remember that almost everything in a smithy is a consumable and will need maintenance and replacement---my first hammer is on it's 4th handle for instance and needs to be re-dressed as 35 years of use has worn the face flat again...I just relined one of my propane forges as students are quite hard on the liners; If I'm teaching a lot I have to reline every couple of years.  If it's only me then it's more like 5 years---of course I don't forge weld in my propane forge which helps.

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One inch thick refractory  cement is way thick.  Cement is not the same thing as refractory liner.  A thin coating will last as long or longer than a thick coating.  Most folks apply a coating of hardener to the inside surface followed by thin coatings of cement and reflective coatings.  Frosty  recommends, and I have found that a piece of ceramic kiln shelf in the bottom works well to ease the wear and tear.

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I always wondered how the ceramic blanket stayed in the upper part of a forge until I built my own. Ceramic blanket is not as stiff as cardboard, but definitely stiffer than the blanket on your bed. Once you press it into the arch form it stays in place by itself and then once you apply your refractory cement (I recommend Wayne Coe's Kast-O-Lite) it really will stay in place. No worries.

Also, a five gallon bucket may not be the best. Try an old portable air tank or a propane tank.

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In my mind it was picturing the ceramic wool being about like insulation you would put in your house. I didn't realize it was so stiff. 

I was wondering about the best ceramic wool because I have heard of like 3 or 4 different brands, and there is a guy in my local blacksmith guild who sells some, but it is just called "ceramic fiber blanket" and I didn't know if there was a best or if they were all very similar. I wish I could afford space shuttle level stuff, but that is WAY out of my budget.

Which is a better option for a forge floor, insulated fire bricks or the kiln shelf? And where do you get the kiln shelf?

I would like to try forge welding. I would really like to try making some pattern welded steel. If no more than to say I did it.

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Ceramic blanket is the usual term when talking to Mffg.  There are different grades according to temp ratting.   Depending of your intended max heat and time at heat different strengths are required. 

FASKAST 80 Castable
Alumina, High
Steel
Ferrous Foundry
 
KAST-O-LITE 20-45 G PLUS Insulating Monolithic
2000F
Ferrous Foundry
EEC
Cement/Lime
 
KAST-O-LITE 22 G PLUS Insulating Monolithic
2200F
Iron
Steel
Ferrous Foundry
Copper/Nickel and other
EEC
Cement/Lime
 
KAST-O-LITE 26 LI G ON-LINE Insulating Monolithic
2600F

To the best of my knowledge Kast-o-Lite is not a cement but a refractory clay composite. The above is from product catalogue http://www.anhrefractories.com/refractory-products

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For ceramic blanket you want to know the temperature rating and the density.  You want at least 2300 F rating and 8 lb. density.  For the kiln shelf I visited a local pottery shop and asked to buy some broken pieces.  As long as they are bigger than what you need they can be easily cut to size with an angle grinder using a cutoff wheel (I used a masonry wheel, but I doubt you'd have trouble with a metal cutting wheel).  You can also order the kiln shelf online or buy new from a pottery supply store, but it's going to be more expensive that way.  Some online places charge extra for shipping kiln shelf because it has to be packed properly to avoid breakage in transit.

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Actually Mike has been the big proponent of kiln shelving for forge floors, and I was going on and on about kiln washes. There are a couple good threads ongoing about building forges. There is good information and discussion about several ways to build propane forges, materials, construction, etc. a whole lot more than I'd care to repeat. It's not that I don't like talking about them I've just said it a bunch of times recently. So please read up on building gassers here and we'll talk.

Frosty The Lucky.

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Thank you WayneCoe! I think I may try to make a ribbon burner on my next forge, but this current forge I already have my burners built. 

I will certainly check out your site though. Thank you again. :-)

Actually,  thank you everyone for the answers thus far. They have been very helpful.

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