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Sideblast fab


Forgingforfun

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I'm sure someone with more experience with sideblast forges than I will be along to assist soon.  A couple of issues I see worthy of consideration:

  1. The washbasin you are using is galvanized and has fairly high sides.  You are going to struggle with both getting your stock into the right zone in the fire due to the sides and potential zinc fume poisoning if the forge body gets too hot.  I suggest you look into the designs for a JABOD on this site, which is fairly easy to construct and low cost (and also answers your question regarding materials of fill):.
  2. The final piece of pipe in your air supply (tuyere) is a consumable, unless carefully water cooled (see classic British sideblast forges with circulating bosh tanks).  Instead of welding it I recommend using a standard threaded plumbing fitting so it can be replaced as required.  Also you may wish to use SCH 80 pipe for that section as the extra thickness will give more life.
  3. As regards welding, you might also consider cutting off the threads on a section of pipe before welding it.  The threaded section of pipe is thinned out and connections of that sort will be weaker (not to mention stress risers from the exposed threads).  Not a big deal for this project, as it isn't a major support area, but still worth consideration for the future.
  4. I see no practical reason for your tuyere to extend that far into your forge "tank".  Most likely the only thing needed in the forge is the smaller pipe.  As currently configured you are wasting a lot of volume that will need to be covered with fill.
  5. Deeper fires are needed for charcoal, but you indicate you are switching to coal (note there is a difference if you are using bituminous or anthracite coal - soft or hard coal in common parlance).
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Galvanized won’t be a problem if you fallow the same guidelines as to fill thickness one dose for wood. The sink won’t get hot enough to be a problem. 

A good adobe mix (1/3 clay 1/3-2/3 sand) works well, the addition of wood ash seems to help keep coal Slag from sticking to it, as dose the lower concentration of clay.

As to bowl shape, I find a slit trench 4” wide with sloping sides 8-12” works well, 3-4” deep (measured from the hearth) or so. I find a wall on each side of the trench further helps keep the fuel in place. 

 

This  should help. The drawings are at a 1” to the square scale.

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Thanks for the tips much appreciated,  I thought pipe nipple at 6 inches was to long also , I planned on the whole setup being consumable, I plan on cutting side down to allow horizontal placement of to be forged stock. Will post pics when setup. Have a cannadey otto blower with 3 inch stovepipe and want to pad area between 2 Inch pipe maybe steel wool. Beings setup is outside under 8 x8 roof, I may hookup blower only when forging and keep it in shed, dont want snow n rain ruining it.

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Understood about heat transfer, as a firefighter...retired...heat travels via conduction, convection and radiation, I will mount on a wooden slash metal plate stand probably with brick spacers,  I pulled 2 inch pipe back to tub edge, and it puts end of 3/4 pipe to center, will cut side of tub to allow stock placement, pic doesn't show end of tub with cutout, that would allow a second path to sweet spot. Will work on tommorow and this weekend, I'm fully aware of galvanized metal fumes and dangers of same thank you all for your time and experience..Much appreciated!

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When I seen your first post I thought you were building a water-cooled side blast forge. In my forge I use a sch40 pipe that I left extra long to push in as it was burned away but after nearly a year it's only lost about a quarter of an inch. It was completely encased in clay and the end was flush with the side of the trench. I just tore it apart recently to rebuild the wood box. I was surprised how well the clay protected it.  

Were you using a 3/4 inch pipe with multiple holes as a tuyere in the tub originally? 

Pnut

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I have that neo tribal video, and followed there forum years ago, neat stuff...using coal with the sideblast I would like to know where the neutral part of fire would be I assume several inches away from tip of pipe ..then up several? My main driving interest is to forge weld tomahawks,  my gas forge doesn't work well enough to do the job, I will use it for every thing else.

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9 hours ago, bill duckworth said:

using coal with the sideblast I would like to know where the neutral part of fire would be

Using a 3/4 inch pipe I have a hot spot about as big as a softball. If you visualize a softball sitting on the top edge of the tuyere and against the side of the forge where the tuyere is you'll have a pretty good idea of where the hot spot in my jabod is. The reducing area is about halfway  up the hot spot in my forge. I use charcoal mainly but haven't seen a noticeable difference between fuel's regarding the hot spot and reducing or neutral zone. Ymmv.

Pnut

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Let us start with a photo of a generic side blast forge.

image.png

The purple is the clinker, or stuff that does not burn, and gathers below the fire.  The ash below the clinker acts as insulation and keeps the bottom of the forge cool.  The sweet spot of the fire is usually 1/2 to 2/3 of the way up the fire ball.  Fuel does not make the fire hot, air makes the fire hot, so I would make the fuel deeper, and then control the air to control the size of the fire.  You can adjust the sides of the forge with brick or firebrick to control the shape of the fire.

Each forge is different so you will need to learn how to use that difference to your advantage. 

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Yes, no user name that I can remember,  but loved the simplistic use of knowledge and tools, that's were I got the wash tub idea from, I do have some charcoal that I may try with the sideblast setup. Btw I found out roofing centers have cheaper charcoal, they use in tarpots I'm told, cheaper than lumber outlets,  aside making it yourself. 

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The Irish Living History group I was president of had a roofer who supplied us with charcoal. He used it for heating soldering coppers to solder valleys on expensive houses that used real copper for them. All the tarpots I have seen have used propane.

I really enjoyed the neo-tribals in the early years when the ego levels were lower.  I remember Tai claiming that he had done the first charcoal forge for NTM, which I found odd since I had used one a decade earlier than the date he claimed and never thought I was first.  Why I now say don't worry about if you are first; worry about who is BEST!

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46 minutes ago, bill duckworth said:

that's were I got the wash tub idea from,

Got to spend an hour or so with Tim Lively back when he was in Tucson. He had a video out, called "Knife Making Unplugged" Therein, he documented the process of cooking bacon and eggs, or eggs and bacon, through constructing a washtub forge, then forging and fitting a finished knife.

Should work great.

Robert Taylor

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  • 1 month later...

It might take some tweaking to get it to get the hearth even with the hot spot but that won't take more than a few minutes. If you have to angle the stock down to get it in the hot spot just dig a little trench from the pass through you cut on the edge of the tub to the edge of the firepot to make it level with the hot spot. No problem. 

Pnut

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