Cast Vertical Forge help

[JTknives]

After doing damascus steel in my current forge i quickley relized 2 things. one, i dont like wool refractory and two, I want a vertical forge. so i got some 10.25" ID pipe today that Is 18" long. what i want to do is give it a cast liner. i was thinging kast-o-lite 26 or 30. do i need the 3000 deg or will the 2600 work. also how thick do i make the walls.i have searched and i can onley find kevin cashen's page that talks about using 1.25" thick walls. any ideas? Thanks

 

[rocketmann]

JT, the forge on my shop tour page was made using cast-o-lite 26 The walls are about 3" thick It stands up to the flux very well (and I use a lot of flux with the cable). I don't know why it is called cast-o-lite because it is anything but light. My forge weighs about 100 lbs. Here is a shot of it cranking along at 2400 degrees.

 

[Stacy E. Apelt - Bladesmith]

JT,
Castable refractory is for the inner shell. You cast the sleeve (1-2" tick), then you wrap that with wool ( or some other insulation), 1" is fine, and then add an outer shell of metal. The outer shell is often thin sheet metal, wrapped and secured with sheet metal screws. If you don't add the wool layer, the outer shell will get hot.

In use, the inner shell surface heats up, and becomes its own heat radiating source. Heating is much more even. It takes longer to come up to heat, but once there it stays steady .

Go with Kast-o-lite 30.

Stacy.

 

[JTknives]

JT, the forge on my shop tour page was made using cast-o-lite 26 The walls are about 3" thick It stands up to the flux very well (and I use a lot of flux with the cable). I don't know why it is called cast-o-lite because it is anything but light. My forge weighs about 100 lbs. Here is a shot of it cranking along at 2400 degrees.

with 3" thick walls how much room is left inside. i dont think i could do 3" walls maybe 2". but would that be thick enough

 

[69_knives]

Do another layer of wool on the outside and wrap with thin sheet metal, like Stacy suggests.

 

[Ed Caffrey]

If your going to build a castable liner, I would suggest making the whole thing out of castable. And yes, 3" is a requirement for most castable refractories. Anything less than 3" and the castable will not provide full insulating value. If you can build a form to cast a liner less than 3", allow it to cure, and then wrap the exterior with 1" of #8 density kawool, it will make a really nice welding forge. Its just a lot of work and you need to be careful with a liner less than 3" thick as it can be rather fragile.
Whatever you do, I would discourage trying to put any layers of kawool in with wet castable. I tried that...ONCE. The kawool will soak up the liquid/moisture from the castable, and will never cure....or at least it won't cure enough to use. On that one, I built, I let it dry/cure for over a month, and upon first firing it, blew chunks of the castable all over the place, essentially wrecking the liner.

Something that I have done is to build a welding forge from kawool (1" thick/#8 density) BUT..I used 3" of castable for the floor, and swept it slightly up the sides. I coated the interior of the kawool with ITC-100 slurry. Its a matter of expense versus ease of repair and use.

Although a solid castable forge will last for a LONG time without needing repair, however the down side is that it takes much longer to heat up (45 mins to more than an hour), and when its done, you have to start all over with a new shell and all. A welding forge with kawool/ITC-100 and a castable floor does require that you replace the kawool more often, but its less expensive overall, and you can reuse the same shell until the shell is wrecked (I've been using the same shell for over 3 years now).

In the end, its really up to you. both have their good and bad points, but either done correctly, and with thought, will serve you well.

 

[delbert ealy]

Mine is cast and is between 3/4"-1" thick.
It is covered with 1" kaowool and thin metal shell.
It is not fragile, I regularly make billets of damascus of 13 lbs and the shells I use will easily see over 1000 lbs of steel run through them.
Del

 

[JTknives]

Mine is cast and is between 3/4"-1" thick.
It is covered with 1" kaowool and thin metal shell.
It is not fragile, I regularly make billets of damascus of 13 lbs and the shells I use will easily see over 1000 lbs of steel run through them.
Del

so if i put say a one inch cast liner on the inside of the pipe then wrap the pipe with one inch of wool refractory then put a thin sheet metal cover over that i will be good. I want it to not use a lot of propane. But could i get away with say just two inches of a cast liner with no wool.

 

[69_knives]

You could no doubt get away with it but the hotter the outside of the forge feels, the more fuel is being wasted heating the outside air. kaowool is cheap and it will easily pay for itself in fuel savings.

 

[JTknives]

You could no doubt get away with it but the hotter the outside of the forge feels, the more fuel is being wasted heating the outside air. kaowool is cheap and it will easily pay for itself in fuel savings.

i have the wool

 

[Stacy E. Apelt - Bladesmith]

JT'
I haven't done it the way you are saying, but it passes through my mind that if the refractory is cast inside a steel pipe shell, the expansion of the refractory upon heat up may cause cracks. Don't know for sure, but you might want to give Darren Ellis a call. He is very knowledgeable about castable refractories. Everyone I know with a cast liner has made a simple mold and cast the liner. Things I have heard of being used have been PVC, cardboard, sheet metal, stove pipe, AC duct, wood.

Stacy

 

[Don Hanson III]

Vertical is the way to go for welding, IMHO...

I use the Fogg style with an 18" dia, pipe and 1.5" of wool coated with satnite. Wool in the bottom cover with cat litter. With a lot of welding, I get 3 to 4 years out of the wool lining. Flux droops to the bottom and doesn't effect the sides much. Cheap and easy and I can reline in about an hour. From my experience, large cast forges are gas hogs.

 

[JTknives]

how do i do the doors. i have some square tubing i got that is 3 plus inches on the inside. Do i put a hole in the pipe and then put the tubing in the hole about an inch and then weld it. Does this protect the wool.

 

[Sweany]

so if i put say a one inch cast liner on the inside of the pipe then wrap the pipe with one inch of wool refractory then put a thin sheet metal cover over that i will be good. I want it to not use a lot of propane. But could i get away with say just two inches of a cast liner with no wool.

Don't put the pipe between the refrac and the wool.

the wool helps keep the heat from radiating OUT of the shell. The wool on the outside of the castable will really improve the performance of your forge.

The pipe would defeat the purpose of the wool.

The pipe will act as a heat sink pulling heat from the castable.

Go to Lowes or Home depot and get a sono tube, carboard tube for pouring cement forms, bucket what have you.

check out this site.

http://www.backyardmetalcasting.com/

lotsa tips on castable

 

[Don Hanson III]

I just cut square front and back door holes and welded a plate in the bottom of the opening to cover and protect the wool. Sq tubing would also work but not really needed.

 

[JTknives]

I just cut square front and back door holes and welded a plate in the bottom of the opening to cover and protect the wool. Sq tubing would also work but not really needed.

that's what i did on my forge now but when the newbies come and play thy keep hitting the sides of the opening with the stock and causing it harm , I love helping people get into knife making.

 

[Don Hanson III]

In that case, I would use sq tubing

 

[JTknives]

In that case, I would use sq tubing

i will try the wool as i have some and as long as i can protect it then thats fine. So will 1 inch of wool be ok for the walls. O and my tub of itc-100 is all dried out. I kept it in the container it came in but i looked at it last might and its all dry. Can i re water it?