pouring a forge table.

[ricejm01]

So I've been toying around with the idea of building a brick forge. However like most of us funds are a problem. so I'm trying to do this on the cheap and use as many found materials or with as relatively in expensive materials as possible. oh and to try and use as little materials possible So i had the idea wouldn't be nice to just get a chunk of stone like a stone counter top and set it on some cinder blocks to make simple forge table. Well I found this in my interwebs searching

http://www.diynetwork.com/how-to/how-to-build-a-concrete-countertop/index.html

so now I have the crazy idea of building mold (with a void in not quite in the middle for inserting brake drum for a fire pot) for pouring a forge table and setting that on four legs of cinder blocks and attach a half hood or metal side draft (a later project). (16 standard cinder blocks 4 per leg), with a table surface around 3'X3' and some flat stock to help support the table between laid across top of the legs.

My only issue with this is that i don't want to use straight cement or concrete because I read about cracking and/or exploding sending hot spall everywhere. So does any body have any suggestions or a refractory recipe that I could use instead of cement/concrete? Or do you guys think that since the fire pot will be an insert that the walls of the fire pot will be enough to block the heat to use cement/concrete, because the fire is not directly in contact with the cement/concrete? If I can find a suitable replacement for the cement/concrete or to just use cement/concrete the whole forge should cost right around 50 bucks for just the materials. I've thought about using metal plate, but cement/concrete just looks seems like a cheaper way to go in cost per surface area.

[kcrucible]

My only issue with this is that i don't want to use straight cement or concrete because I read about cracking and/or exploding sending hot spall everywhere. So does any body have any suggestions or a refractory recipe that I could use instead of cement/concrete? Or do you guys think that since the fire pot will be an insert that the walls of the fire pot will be enough to block the heat to use cement/concrete, because the fire is not directly in contact with the cement/concrete? If I can find a suitable replacement for the cement/concrete or to just use cement/concrete the whole forge should cost right around 50 bucks for just the materials. I've thought about using metal plate, but cement/concrete just looks seems like a cheaper way to go in cost per surface area.

Yeah, I'd avoid concrete, at least within say 1ft of the fire itself and a bit more is safer. The heat WILL destroy it in short order. On my blog I have a link to suppliers that you could buy refractory from. The refractory is insulative, so would tend to make your firepot/brake drum hotter. Normally I'd say that's a good thing... hotter fire, but it might make it so hot that you start melting down the steel if it can't radiate the heat away!

The cheapest place I've found for refractory "on the net" is Ellis Custom Knifeworks. Despite a shipping snafu it eventually got cleared up. You'd want the insulating 2600 probably. If you can find a local supplier you may be able to get it cheaper and no shipping. AF Green is one of the producers, so you can look up their distributors.

I think you could use one bag of 55lbs to cast the firepot then surround that with normal concrete to keep the cost down. The heat that gets through the insulation should be much less severe and won't break down the concrete. Thicker is better, so could go with 2 bags. Building sides and a lid out of it would make it that much more efficient.

This material is commonly used for gas forges. Probably not so much for coal, but there's no good reason why not as far as I can tell (other than it's "new fangled" which is a little antithetical to the traditional methods I guess.)

so now I have the crazy idea of building mold (with a void in not quite in the middle for inserting brake drum for a fire pot)

Here's a better idea... if you're going to all of this trouble to cast a table, why not just cast your firepot directly into it? If you cast it out of insulative refractory material you can probably save money on fuel costs. So, more expensive initially, but should pay for itself in the long run.

[ThomasPowers]

Me I'd just scrounge firebrick from fireplace demolitions and set it in with fire clay from the local masonry supply yard for the forge table and use whatever I found for the rest of the masonry that won't be in close contact with the forge fire.

[Sweany]

Excerpt from the old Keenjunk site.
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Kevin, depends on the rating of the clay you have, you'll have to add some stuff to it to keep it together. You'd need some stuff in the mix to keep it together. And a flux to, sinter it. If you exceed the heat limits of the refract it will melt .

Kawool is faster heating and lighter.

I realize the following is a crucible recipe but it shows some of the principals involved.

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Crucible recipe from a clayart thread

I saw one a couple of months ago a Behrens' formula I think

Epk 40
Calcined Kaolin 20
Tennessee Ball Clay (OM #1) 20
Grog 10
Flint

mix with about 500ML of water per 1000 grams mix. After an initial
wetting period of about 24 hours allow to mature for a week before
wedging and throwing. Fire to Cone 4 or higher

There's another way to go with the help of your friend.
You'll need to get investment from him. Then mold a lump of clay into a
mound. This will shape the bowl of the crucible. Set the lump onto a
smooth surface and build a wall around it with clay. Mix the investment
in a ratio of 38-40 parts of water to every 100 parts of powder by
weight. Then stir in 1/3 to 1/2 as much pumice as there is investment.
Pour the mix into the form. Vibrate it to remove air bubbles. Let it set
up overnight then fire it to 600 degrees Fahrenheit. Let it cool slowly
in the air.
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another one from the junkyard
Ed

I have had pretty good success making my own castable refractory material. 4 parts premixed concrete, 4 parts fire clay (available at masonry supplies), 1 part vermiculite. Mix with water to the desired consistency. Let sit over night and bring heat up slowly for first fire.
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I've read pearlite is better in this mix, pearlite does not soak up water like the vermicullite.

[twcoffey]

All you need is a piece of 1/4" steel plate as a table with your forge set into a hole in the plate. Put some legs on it and your done. No Masonry required.
The only high heat is in your fire pot and although the table will heat up it will be well below 300 degrees F.

Ted

[Frosty]

It's a lot easier than trying to form and pour a forge table. Concrete will NOT survive long at all, minutes if you get a good fire going.

The first wood forge I built at about 10-11 yrs. was an old top loading washing machine I turned the door over, cut a hole large enough a brake drum would fit and rest on the wider rim, leaving about 1 1/2" sticking up above the old lid. Then I rammed the lid full of adobe clay only just wet enough to stick together.

Then I hooked up my air with plumbing pipe and fittings to the brake drum from underneath and used an old style hair dryer for air blast. The air grate was a piece of plate with a bunch of holes drilled in it.

It worked fine and would still work but that was near 50 years ago.

Don't over complicate the thing, a forge is a "fire place" and unless you're doing something special it doesn't need to be much at all. For centuries a forge, even shop forge was a hole in the ground. Old school portable forges were most often wood with a clay or dirt liner to keep it from burning.

Keep it simple, the simpler the better. Once you've developed yourself in the craft is the time to start thinking of specialty tools and equipment.

Frosty the Lucky.