Sunday, July 01, 2012

Escential Smelting Tools

Question : What tools are absolutely required for an iron smelt?

I think these are the absolute minimum

L-R : Radner / Bloom Hook / Bloom Tongs
A length of roughly 1/2 diameter round mild steel rod, about 3 feet long plus.
One end cut flat and square, the other end forged to a blunt chisel tip.

This needs to be small enough diameter to easily fit down the inside of your tuyere. The square cut end can be used to clear slag blockages ('uvuloids' *) that form on the interior end.
The tool reversed to the chisel end can be used to poke holes into the lower slag bowl for slag tapping.

For a historic presentation,  I would suggest taking a piece of 1/2 square and forging it down to an octagon shape. This will produce both the desired profile, but also remove the modern machine made edges and look.

2) Bloom Hook

The working end forged from something like 5/8 square or 3/4 x 1/2 flat. It should have a right angled bend ending in a steep point, about 2 inches along the bend.
Mike McCarthy showed me the mounting system seen in the image. This allows for the attachment of the shorter working end on to a (replaceable) wooden handle. The metal has the upper end forged to a short right angle bend (same side as the lower hook). A forged metal ring (in this case made from a short section of steel pipe to save the time welding a ring) holds the working tip to the handle. You can see the wood is prepared by cutting a hole and a slot near the end. When the ring is driven on, it locks the working tip on to the handle.

Mike's handle attachment system

This is a pretty versitile tool. As a hook it can be used to pull loose a bloom for top extraction. It also can serve as a rake to pull free hot slag during tapping.

3) Bloom Tongs

On either top or bottom extraction, you are going to need a pair of oversized tongs to grab the bloom with. The style shown here is pretty much as simple as these can get. Made of roughly 3/8 x 3/4 flat stock. The full width is maintained at the pivot point (hot punch for a 1/2 diameter rivet). The metal is then collapsed down from rectangular to flatten at 90 degrees to the original orientation for the jaws.
On mine I cheated and welded on two sockets forged down from pipe. This allows replaceable wooden handles. Remember that you need enough length to allow you to reach down inside the furnace if you intend top extraction - that is at least 32 - 36 inches total. An alternative would be to make them up to use the ring and slot system described above. (Or just go for a full metal rein?)
 I have adjusted my bloom tongs so fully closed there is about a 1 inch gap between the jaws. More importantly, they are set so that with the jaws open to roughly 6 inches, the distance on the handles at the mid point is only about 10 inches. (This so you can get the jaws around a larger bloom, but still fit inside a standard furnace diameter.)

Things you need - but likely have around already:

4) Knife

You are going to need to cut into the clay walls to set the tuyere and make your tap arch. Obviously you can just use your belt knife for this. Personally, I don't like to use my working knife for this (wrecks the edge) and so keep a 'garbage' knife in the smelting tool box just for furnace construction.
Outside a historic situation, a small dry wall saw works wonders - especially if you are using straw cobb construction.

5) Medium / Large tongs

These would be the same sized tongs you would use for working larger diameter stocks (adjust for roughly 2 - 3/4 thick materials). The same size you would keep for working axes and the like. These for handling the bloom as it is cut into pieces and compressed.

6) Sledges

Again the same tools you would use for working heavy stock sizes. I normally work with two strikers, and keep two hammers in the 5 - 8 lb range on hand. Since I normally am not working with skilled *blacksmiths* during iron smelts, I find the lighter sizes allow for the required control.

7) Axe

For cutting the hot bloom. You *could* use one of your splitting axes for this. I personally keep a dedicated (cheap and pretty rough) axe just for bloom splitting. The combination of extreme heat and pounding will pretty much destroy any axe as a functional woodworking tool afterwards. I have wrapped about six inches of the handle below the head with leather to protect the wood.

Things you can get by without - but are nice to have:

8) Rake / Hoe

Mike also showed me a simple flat plate on a handle style, all made of wood. Kept soaked, it deals with raking away ash, burning charcoal and hot slag pretty well. Fast to make and considered a disposable.
Of course a small garden hoe works very well here.

9) Shovel

I personally like to keep all that hot stuff picked up and kept well away from the work area. In the frenzy of a major slag tap, or during extraction, the last thing you want to have happen is kneel on a hot bit of something! Again, in a historic situation, a simple wooden shovel kept soaked down works fine.

10) Ore Scoop

With gloves, its certainly possible to just pour your charcoal straight from a bucket into the top of the furnace. For ore additions, I personally like the control of a small scoop with a handle on it for adding ore. This also allows you to use a 'standard measure' for your ore additions. Can easily be made of wood as much as metal.

For top extractions


Mark Pilgrim, using the Thumper for Vinland 5

This is a roughly 4 inch diameter log section, with handles on the other end. I use a piece about 30 - 36 inches long, plus the handles (enough to reach the bottom of the furnace). This is used for compressing / loosening the hot bloom in place down the inside of the furnace. Not everyone uses this particular step, but we have found it effective.


This is a shallow bowl, about 4 inches in diameter made of heavy steel plate, set at right angles to a long handle. Again the ring and slot system can be used to secure a longer wooden handle to the working end.
This is needed to clear the last remaining burning charcoal from the furnace to expose the top of the bloom.

For bottom extractions

Pry Bar

Lee uses a length of roughly 3/4 diameter bar about 4 feet long to shove the bloom *up* to loosen it when doing his standard bottom extraction. The bar has a short 'sheppard's crook' end to it to increase the leverage and reach up inside.

There is also a section on smelting tools as part of a consideration of the Vinland / Norse iron smelt in my paper 'Iron Smelting In Vinland' - (as a pdf)

* Correction added by Vandy:

Do you mean 'uvuloids' as in "uvula" the bit at the back of the throat, and Dairy Queen commericals?

Yup - that is exactly where the term originated. Blame Mike McCarthy!

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February 15 - May 15, 2012 : Supported by a Crafts Projects - Creation and Development Grant

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