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I Forge Iron

Forge Hoods Explained


Glenn

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  • 1 month later...
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Well, I took advantage of the sunny day today and almost finished my new coal forge project. I bought another fire pot from Dave Custer and installed it. I really like those fire pots!

I still have to mount my blower and the tabs for the small opening piece. The culvert stack is 16" diameter. The table size is 42" square.

I bought this from my local industrial surplus store cheap. It was new and never used. It originally was a hopper made for the Philip Morris company. Now it's a forge/smokestack.

How's that for irony!

Thanks again for all of your input guys!

16_INCH DIAMETER STACK.jpg

DAVE CUSTER FIREPOT.jpg

PROJECT CONCEPTUAL.jpg

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First test of the new forge and Wow!! I can't believe how great it draws... I set some lump charcoal in it with a small wad of paper and it took off

like a F-111 in full after burner. And that was without using the blower! My buddy and I forged for 4 hours Sunday and I've never had a better

fire to work with. We hardly had to use the blower, only when we needed the extra heat.  hat  36" tapered cone and 16" diameter stack must work like a super vortex.

Very happy with this project. Now on to the surface grinder/belt grinder project...

Video here

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  • 1 year later...

I am building the Mark A. design Side Blast Forge. The location for the tuyere has been determined but is yet to be installed.

I built the Lester Beckman Super Sucker Hood and am getting ready to mount it above the Tuyere.

My chimney is a 10" steel grain auger tube. The chimney was cut in two because of a large kink in the middle.

This is my mounting plan: With the Tuyere mounted thru the side ofthe Hearth, the hood will also be mounted to the same side of the hearth just above the end of the Tuyere.

From pictures I have seen of the Supper Sucker Hood, it is drawing smoke and fire from the forge into the hood. 

How far above the Tuyere and back from the end of the Tuyere should the Super Sucker Hood be mounted?

I am concerned about how hot the hood and lower pipe could get. The steel square tubing that I want to use to mount the hood is galvanized. Will the hood get hot enough to vaporize the galvanize off the mounting tube?

There will be 10' of chimney going straight up inside the building and another 10' above the roof. How hot can I expect the hood and chimney inside the building get? The chimney will be in contact with the steel mounting bracket and the sheet steel roofing where it passes thru the roof. The steel chimney supporting brackets are 4" from a wood beam.

 

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  • 1 year later...

Appalachian Area Chapter of Blacksmiths (AACB) has been building and using portable forges with side draft hoods (see photos) since 2013 for training and their conferences.  The design allows them to be used from either side of an open shed or tent.  The hoods measure 5 ft. long, 12 in. sq. with a 6 ft. tall 10 in. dia. spiral pipe.  The forges use electric blowers with butterfly valves that have controls going in each direction allowing the operator to control the air from either side of the forge.

The horizontal part of the hood is made from two pieces of 1/8 in. (11 Ga.) steel measuring 2 ft. x 5 ft., bent lengthwise and tacked together to form the five foot duct.  Then a 12-in. sq. piece is tacked to one end of the duct, then the seams are welded together.  Next, the fire end is cut at an 75 degree angle and plated with three pieces of 1/8 in. x 3 in. flat stock to form a flange to cover the opening, with one inch towards the inside and two inches toward the outside on the sides and top.  The bottom of the flange is 1.5 inches and goes only to the outside and goes straight down (nothing to the inside).  The hood is a perfect place to store the flue pipe when transporting. The late Lester Beckman who was known for promoting the side draft hood told me that the 3 in. plates lining around the opening is one of the big key things that make the side draft hoods draw so well.

To finish, cut a 9.75+ in. diameter opening for the flu pipe near the closed end, make a 1.5 in. flange from 1/8 in. or thinner material, and weld it around the opening.  It helps to wrap this flange around the spiral flue pipe material that is recommended as it is much more rigid than regular duct work.  You will need to support the vertical spiral flue pipe as well as the five foot horizontal duct.

When starting the fire outdoors you will need to put a little amount of burning paper in the hood to just start the draw, then once it warms up just a little it will roar.  Side Note: Lester told me that if the flue pipe end of the sq. tube was cut at an angle (45 degrees or so) it would draw better (no square corners).

Hope this will help someone out.

Slowpoke 

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125431549_2829979407278770_6709490395738619620_o.jpg

Edited by Mod30
Fixed the degree angle.
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  • 2 months later...
 A buddy of mine has an old satellite dish made of 1/8" thick aluminum with perforations throughout.  He said I could have it for free.  Thinking it might make a good hood form that I could cover in rock and refractory cement later.  I know it melts at 1200 degrees but it would be easy to cut with a sawzall and form to my imagination.  Any thoughts?

Image preview

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Forge hoods work best when they are ONLY pulling in hot smoke from the forge A wide flattish dish  spaced a distance above the firepot will pull in mostly cold room air and not work well at all. I was given a solid dish with an 8" duct off of it and it didn't work well at all.  Now I use a 10" spiral seamed round duct that comes down close to the forge and has an apron that encloses 3/4 of the firepot and duct and works pretty good.

 

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I don’t know what happened with the pic, sorry.  I didn’t mean leaving the dish in its original shape.  I would cut it with reciprocal saw and reshape the perforated 1/8” aluminum to fit my 4’ diameter fire pit.  I would tighten the cone to 12” pipe on top.  Then cover with rock and shape 3 arches to my imagination.  I have heated my house solely with wood stove for past 17 years with 20’ long flue.

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This is that 7' diameter aluminum 1/8" thick+ dish I can get for free to build forge hood on my ground firepit.  Using a truncated cone formula layout a 4'diameter firepit would be 13' base circumference and the top of cone would be 1' to accept 1 foot exhaust pipe.  My reciprocal saw would make fast work of this see-through thick perforated aluminum.  Resizing it cold hammering.  Even 3 arches could be cut.  My forge is used as a regular firepit for entertainment and a forge, all I need to do is adjust air accordingly.  Their is already existing rock that the cone will sit on.  The cone can eventually be covered with smeared fireclay then rock.

image.png.7426d6f2b44d70a28f5d5c6c33da0125.png

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I'm thinking you should cover it with rock, stand it outside and when you have friends over play the Flintstones on TV. 

A side draft hood will work a treat even for a cook fire, much better than "conventional" smoke hoods. 

I thought a solar forge would be a cool thing but started to think about how dangerous the INVISIBLE solar death beam would be. A 4sq foot Fresnel lens burns flaming trenches in wood in seconds. Be fun if I could figure out how to make it fool proof safe but we know how clever fools can be. No thanks I don't personally want to help chlorinate the gene pool.

Frosty The Lucky.

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