Bentonite as a furnace lining?

[Peter.]

I plan to make a furnace using a small propane bottle for a casing and a propane burner. I have a 11kg bottle which I'll cut the lid off, and I have a 25kg bag of Bentonite clay with a chance to grab one or two more this week. I understand this clay is used as an ingredient in casting sand but will it make a good lining for my furnace?

Pete.

 

[d.bick]

Peter
I’am not sure about using bentonite as a furnace lining. I used ganister, which is
cheaper than some of the refractory linings available. As You said the bentonite can be used to make up your own molding sand.
Dave Bick

 

[tel]

Bentonite won't be of any use to you as a furnace liner, far better to get hold of some castable refractory (any potter's supply place) and make a proper job of it, it gets rather hot in there.

 

[Peter.]

Aah right - I kinda had it in my head that bentonite could be used - I'll keep the bag I have for making green sand and find some proper refractory.

Thanks for the advice

 

[Tin Falcon]

Peter : If you want o make your own lining you need fire clay from the local masonry supply . Mixed with sand an grog (Crushed scrap ceramic). But I agree with tell that you best choice would be castable refractory.
Tin

 

[db6261]

Hi, this will be my first post as I just signed up. I would like to make myself a foundry without refractory cement if possible. I believe I have found some fireclay on a hill on the side of the highway and have acquired some. I plan to use a metal 5 gallon bucket for the container. Can I get some help on what to use from there? Thanks.

 

[ddmckee54]

db6261 - This is a great site for machining but for home foundry information I would suggest that you visit http://backyardmetalcasting.com/index.html. You will find info on burners, furnaces, refractory material, crucibles and much more.

Long time lurker,
Don

 

[doubleboost]

Hi
You might get away with home brewn refractory for melting aluminium but if you plan on using bronze i would go for commercial stuff
The other alternative is to make it square and use fire bricks
John

 

[Peter.]

I watched you bronze casting videos after seeing your threading vid John - you make it look easy and the results were great!

 

[Rocket Man]

All you really need to do is buy some good fire bricks from your local boiler supply company. Stack the bricks in the shape you want, square furnace, with no cement. You can keep the brickes under the work bench out of the way until you decide to use them again. Bricks come in a cardboard box about 24 to a case. Bricks are almost as light weight as styrofoam and rated about 2500 degrees F. You can hold a brick in your hand with no glove and heat one side red hot with your oxygen/acetylene torch.

If you call Dave Bockman at Allied Boiler Supply (800) 858-0484 he can give you a price on bricks and mail them to your front door.

 

[JorgensenSteam]

I would use extreme caution if cutting into an existing drum, cylinder, etc. as they can explode due to residual fumes.

The only safe way I know of is to fill them completely first with water and then get the cut started.

I made a temporary furnace using stacked fire bricks.
It was a bit inconvenient to have to remove the top bricks to extract the crucible, but it did actually work quite well for melting aluminum.
You can store the bricks inside once they cool, but they do tend to break up over time if you handle them.

 

[tel]

As you say Pat, the fire bricks work, but they are terribly inconvenient unless you can set 'em up permanently under cover somewhere. I have two furnaces made with the refractory in metal casings (one an old LPG bottle) and they can be moved around and/or stored with relative ease.

 

[willburrrr2003]

I use #10 Lincoln fireclay from my local pottery supply store.

Regards,

Will

 

[f350ca]

Don't mean to steal this thread, but a quick question as firebrick has been mentioned. I have access to a bunch that was removed from an incinerator at a hospital, they.re the heavier type, guess not as good at insulating. They've been outside for some time, but not split from water freezing in them. How should they be dried. I'm guessing they'd explode if heated in they're present condition.
Greg