remidw

First Forge Refractory

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Hey everyone,

I recently made a gas forge using k26 firebricks and a 1 inch Gameco burner. The forge worked well but there are some problems that i have to address. The first problem is that the firebricks are not strong enough and some of them have broken. I was thinking of replacing these with Kast-O-Lite 30, i have been reading a bit in Forges 101 and i'm not sure if only that will be good enough.  The second problem is that the burner flare gets too hot and should be moved up in the refractory, this can be fixed easily. If needed I will rebuild the forge. Any ideas to fix this?

Greetings

Remi

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In general insulating fire bricks are notorious for cracking and crumbling after repeated forging sessions.  However, there are some members here that swear by K26 bricks of the Morgan Thermal Ceramics brand.  They can be found on Ebay.  I have not used any of those bricks yet so I can not tell you from personal experience how they compare, but they definitely get favorable reviews on here by those who have used the bricks.

Your flare is going to get hot.  It is a consumable item, but moving it up into the bricks and out of the main forge chamber will help it last longer.

The long piece of pipe attached to the 90 degree fitting at your burner concerns me a little.  A little force on the hose end of that pipe will translate into a lot of force at your burner.  In the least case this could cause alignment issues in your burner.   In the worst case you may have a break there and if your forge were in operation at the time that would obviously be a bad situation.   If you're trying to keep the hose out of the hot zone that's a good idea.  Consider using copper tubing to resist the heat and still be flexible enough to give before causing a break at the burner or knocking your burner out of alignment.

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5 hours ago, Buzzkill said:

 

Thanks for the reply! I will look in to those Morgan Thermal bricks. xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx  I understand you're concern on the long piece of pipe. But this would seem strange to me as Gameco sells them like that.  I could of course always make something to hold up the hose, so that there isn't any force on the burner.

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Would Kast-O-Lite 30 be as good as using firebricks? I would rather use something castable .

 

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Kastolite is more durable, but not as insulating.  That's why you see the recommendation for ceramic fiber blanket with a layer of castable refractory lining the inside of it in the Forges 101 topic.  For a squared forge you may also want to consider fiber board.

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Ok, do you think that it would be possible to put a kaowool fiber blanket in this forge and then line it with Kast-O-Lite? 

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Welcome to IFI  Remi... I always suggest reading this to get the best out of the forum. READ THIS FIRST

It is possible to line the forge with Kaowool blanket ridgidized then a coating of Kast-O-lite, there are several forges like that in Forges 101.

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Thank you, i'm pretty sure that i will use Kaowool blanket and Kast-O-Lite. I'm not sure if i will use the same forge body since its build around my firebricks. And could use some improvement: the walls of the forge should probably be thicker since they are only 3mm thick. The first time the forge got hot the walls around the opening melted and bent thats why I had to cut the opening bigger.

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I don’t know how easy it will be to get K26 IFBs in Belgium. The K26 seem to be made in the USA and the JM26 equivalents are made in Italy iirc. The specs don’t usually include anything on resistance to thermal cycling. I think it’s basically a case of forge builders in the USA having found that the K26 IFBs seem to hold up better than others that have been tried.

I don’t know of a source of KastOLite30 in smaller-than-full-bag quantities in Europe.  

If you have to buy a full bag of 25kg, 55lb, I’d probably try casting a lining in the IFB Forge you already have first and keeping the rest for planB.

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I got the Firebrick from a site called Kachelmaterialenshop which is located in the Netherlands.  I have found a possible supplier for the Kast-O-Lite 30. The only thing that I still have to look for is the Kaowool, but i can probably find this pretty easy. 

 

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If I were to redesign the forge i would make it like this. The forge is inspired by Alec Steele's double burner forge except it is just one burner. The inner dimensions of the forge would be 20cm by 20cm by 11cm. Making it 4400 cubic centimeters or 268 cubic inches. The outer walls of the forge would be 5mm thick, it would have a layer of kaowool in the top and bottom of the forge covered with Kast-O-Lite. The sides would be made of only Kast-O-Lite. This Forge can be fitted to the cart that i already have made. I made a quick sketchup drawing to show the idea. Any opinions/improvements i could make to this? Thanks

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8 hours ago, Buzzkill said:

In general insulating fire bricks are notorious for cracking and crumbling after repeated forging sessions.  However, there are some members here that swear by K26 bricks of the Morgan Thermal Ceramics brand.  They can be found on Ebay.  I have not used any of those bricks yet so I can not tell you from personal experience how they compare, but they definitely get favorable reviews on here by those who have used the bricks.

"In general insulating firebricks are notorious for cracking"; just so. I recommend Morgan K26 brick over any 2300 F bricks; especially the old foamed clay type. If handled carefully, it will last; this does not make it a structural item. If used as a forge ceiling it should have a high alumina kiln shelf below it to take the wait of a burner assembly. And the brick should have a refractory coating, like Kast-O-lite 30, to armor it somewhat.

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If I were to cover my Kaowool with Kast-O-Lite, would I have to ridgidize the Kaowool then?

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No. Rigidizing the ceramic fiber blanket with fumed silica in water is always worthwhile, but a long way from a necessity if you are going to cast a minimum of 1/2"  Kast-O-lite refractory. On the other hand, if you plane to trowel the refractory on the fiber insulation it must be rigidized first.

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Okay, thanks a lot for the help! I'm pretty sure that i want to redo the forge, i'd like to make it like the illustration that i posted. Having two inches of Kaowool and around 1 inch of Kast-O-Lite.

Would you think that this is a good design for the forge?

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1" thick Kast-O-lite would make since in a ceiling slab, but 1/2" is plenty thick enough for the walls. For the floor, you would do well with Thermal Ceramic K26 bricks beneath a 1/2" layer of the cast refractory. Or, you could replace the ceramic fiber completely with the brick, so long as you don't replace the cast refractory.

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If I use wool all around would that also be good, instead of using bricks in the bottom? What temperature would the ceramic wool have to be rated at? I have found some that is 2600 degree rated or would 2400 also be good since this is a bit cheaper? Also thanks allot for the help and info you've given me. 

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I finished the forge a couple weeks ago. I used 2 inches of Durablanket Z and 1/2 Inch of Dense refractory. The outerwalls are 8mm thick. So far this has hold up pretty good, it takes a little while to heat up the dense refractory layer. Once heated it is pretty hot and I can easily let the burner run at the lowest possible pressure for regular forging. I will probably coat the forge with a layer of satanite.

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