Forge (Furnace) Liner

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Hello folks. I am in the process of making an old gas BBQ into a portable forge. I want to line it with furnace liner. I have a recipe that I printed from this web site but am at a loss to find out what one ingredient is. The recipe is:

4 gallons fireclay, 4 gallons silica sand, 3 quarts borax powder and 4 gallons of grog.

What is grog??

I sure hope you can help me out here or if you have another recipe for forge liner, I will glad to get it from you.

Thanks in advance.

Brian in Ottawa

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Posted · Report post

Grog is small pieces of fired clay. It, like the sand, will help control shrinking. It should be available from a ceramics place, if they carry raw materials. I think Dick BLick art materials can get it too. They are online.

Jeff

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Posted · Report post

The recipe is:

4 gallons fireclay, 4 gallons silica sand, 3 quarts borax powder and 4 gallons of grog.

I sure hope you can help me out here or if you have another recipe for forge liner, I will glad to get it from you.


That mix is going to be heavy. Are you making a gas forge or a solid fuel forge.

If you are making a gas forge, I would suggest getting some Kaowool from a kiln or pottery supplier, and some Kaowool Rigidizer from Thermal Ceramics. It will be much lighter. Oh and don't buy the Kaowool from Thermal Ceramics, not unless you "want" a 7 metre roll.


Regards Charles

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Posted · Report post

Thanks for the info Charles but I am building a coal/charcoal forge.

Brian

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Thanks for the info Charles but I am building a coal/charcoal forge.

Brian

That's cool, how low tech do you want to go? My first forge was a wooden box lined with hard firebricks. I have since found ways to make even simpler forges.

The simple forges are cool as you can make them very large, and they cost next to nothing to make.


Regards Charles

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Posted · Report post

You may want to look at the Blueprint BP0300 on Getting started in Blacksmithing.

BP0133 the 55 Forge and BP0238 55 Forge/side blast are very simple to make forges that work. Neither forge is lined but uses ash as a insulating material. There is other information there you may find of interest as well.


Even simpler, a piece of pipe, with holes drilled along it's length, dig a trench in your back yard, keep the drilled holes pointing up, bury one end in dirt, fill the rest of the trench with charcoal or coal, blow air through the other end of the pipe.

The only real draw back is that if the wife catches you :-D

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Posted · Report post

I scavengened a gas bbq from the garabge. I have cleaned it up and painted it black and am looking to fill the inside with the liner. The plan is to drop in a fire box and fill the area around it with the liner material. I will be have a 3 inch pipe connected to the fire box out the bottom of the forge to another 3 inch pipe which will be connected to my blower. There will be ash dump at the bottom of the down pipe and air damper in the side pipe.
I will also be cutting down the sides of the bottom section of the BBQ/forge so that I can move long/large pieces into the fire.

Brian

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Posted · Report post

You can use castable refractry or fire brick or any number of fireproof materials to line the forge and forgo the firebox.

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Posted · Report post

I scavengened a gas bbq from the garabge. I have cleaned it up and painted it black and am looking to fill the inside with the liner. The plan is to drop in a fire box and fill the area around it with the liner material. I will be have a 3 inch pipe connected to the fire box out the bottom of the forge to another 3 inch pipe which will be connected to my blower. There will be ash dump at the bottom of the down pipe and air damper in the side pipe.
I will also be cutting down the sides of the bottom section of the BBQ/forge so that I can move long/large pieces into the fire.
Brian


Cheap would be rammed dirt. Castable refractory would be more expensive, maybe 165 ARC from Foseco, it sets overnight (ready to take heat the next day), has a high heat shock resistance, and is solid enough to make a weigh bridge out of.

You could use Kaowool, and cover with a castable refractory.

There are endless possibilities.

Regards Charles

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Posted · Report post

Kitty litter, the cheapest kind (bentonite, not fuller's earth), and certainly use the unscented kind. It should dissolve into mud when wet if it's the right kind. Mix in a bag of perlite or vermiculite (potting soil additives), then when it dries, fill in the cracks with more of the same. It should be less than $10 to fill a forge that size.

Michael

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The cat will be upset (hahahahaha!!!) when she sees that I am heading outside and not cleaning out her box with the new stuff.

Brian

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I made some refractory for a small foundry using sillica sand, fireclay (Hawthorn bond), Mizzou, perlite, and sawdust.
The sawdust will burn out making the mix more insulating. Any kind of fireclay will work.
I let it set up for a month befor firing. I then fire it as if it were ready to go. I melted some brass and had no cracks when done.

Fred

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I made a forge from an old barbeque too. No liner. The funnel shaped coal box is made from mildsteel is surrounded by an air box. I blow my air in that box, it come out the bottom preheated and it cools the funnel at the same time.

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