My Forge

Here is how I built my forge.  Inexpensively.  The boards you see are treated dog eared pine picket fence that has been run through a planer.   The supports are scrap 4×4 from old fences, cut with a 30 degree taper on two sides to support a hexagonal shape.   Like a bee, a lot of what I build has a hexagonal cross section somewhere.

Forge Framework

This picture is not much different, but it does show the shape a bit better.  Inside is my old favorite tool, a Royobi 18v drill.

Forge Framework

From the top you can see the pipe with it’s holes and the framework that supports the thing.

Forge Framework downview

Here is a better closeup of the pipe.

Forge Holes

The pipe sticks out at two ends.  The far side, is connected to a small wet/dry vacuum.  Serious overkill in the blowing department.  I have an adjustable slide on the front hole.  When the forge is running, I can reduce the air flow by opening the slide.  The extra air blows though cooling the pipe and actually cooling me, so I have few complaints.

Forge Pipe end

Here it is all ready to be insulated.

Forge Frame Complete

This is an old welders blanket.  Supposed to be fire proof, it isn’t.  It won’t burst into flame so that is good enough.  This is just to keep stuff in, not really do much protection.

Forge Welding blanket

This is pearlite.   Basically lava glass, that has been puffed up.  You see this stuff in potting soil a lot.

It is light, insulates,  and does the job well.

Forge Pearlite

This is builders lime.  I pour a few bags of it into a plastic trash can, cover with water, and let sit for years.  The longer it is wet, the better it does.  I use this because it holds shape, insulates, and as the heat cracks it, it can be wet and repaired.

Forge Builders Lime

This is furnace cement.  I made a large plug of the high heat stuff below the area where the fire will be, and also coated the pipe with it, to protect the pipe a bit.  The pipe will have to be replaced every now and then, but that is expected.

Forge High Heat Goop

Three or four holes would be enough, but I can stop them with clay plugs if I am getting too much air.

Forge Ready for First Fire

Here it is after the first fire.  I used regular charcoal, and just let it burn.  I did not want high heat so much as to dry it all out a bit before the high heat.  Forges are normally hot and wet, but the furnace cement will fracture badly if it does not dry out before it is cured to a high temperature.

Forge After first fire

Here it is after the first high temperature burn.  All ready to go.

Forge After Burn

Here is the finish the furnace cement put on the pipe.  Nice and solid, this will reduce oxidation of the steel so the pipe will last a good long time.

Forge Glazed Air Holes

The walls on the forge are a bit too high.  I am going to have to cut out a bit so that the long work I heat up can remain level.

Forge Cracks in Putty

With this forge, I have tons of room to arrange fire bricks to make small ovens and pretreat coal.  It is big enough to work fairly large steel plates, much more than I usually need to work.


6 comments to My Forge

  • Skip J.

    Hello Bob;

    Looks kinda like SCA stuff, I believe you have returned to the beginning here….

    Which tools are you heat treating??? Just blades/chisels – or more detailed metalwork???

    What are the benefits to you of doing you’re own heat treating?? Certain custom-made metal parts I presume???


  • I am still working on my blacksmithing skills, but it does allow me to temper O1 steel to perfection, and to have a very quick turn around on tool making. I plan to heat up the forge this week to make a few critical parts for the treadle I am working on. I have been trying to keep the treadle plan simple so that anyone can make it, but I may have to offer a few parts, just so the project does not become too complicated.


  • Skip J.

    Ok – that makes sense.

    A treadle lathe or a treadle drillpress or a treadle jigsaw?????


  • The treadle table will be a worktable with a generic power supply. Lathe head and dogs can be mounted, as can sanding belts, grindstones, and all manner of other gear. I am planning a horizontal drill press since there is an amazing amount of overlap in parts between a drill press and a lathe. The first thing I am going to do however, since it is easy, is set up a grinder.


  • fitzhugh

    Ah, cool – how has the treadle table fared? Just last week I sketched out plans for a treadle to incorporate in my not-yet-built new bench, figuring there is a lot I could use it for, adding stuff as money and time allowed. I would love to see what you came up with since you have more experience. Would you mind emailing with any info? I searched your site but did not find anything.
    Thank you.

  • Bob Strawn

    So far, my treadle experiments have been rather weak. Eventually I need to get back to them. I have made a few sketches of an adjustable treadle, but have not really done anything with it.


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