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New forge, side draft hood not working well


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Hello folks!

I finished my first forge today with putting a side draft on. However it dosent seem to be drafting that well. Was hoping I could possibly get a few pointers from some folks. I am using lump charcoal for fuel. The side draft is 23" tall 24" wide and 10" deep with a 6" diameter stack that is 10' tall. I apologize for the looks of this thing... It's not the best looking but it works (except for the side draft) and all parts were scrounged. The fire pot is 13" x13" and 5" deep. I've seen some other pics that have a "hood" over the opening going to try and put one on tomorrow. If anyone has any words of wisdom I would appreciate it. Thank you

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The most likely problem is the 6" diameter stack. The normal minimum recommended is 10". I suggest that you take what is probably 2 sections of 6" stove pipe and put them together to make one 12" dia x 5' stack. That should work. 

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My side draft has 12" stack, 14' tall, through the roof.  I always start a paper fire in the hood while I am starting the coal/coke in the forge.  The smoke turns sideways and goes up perfectly.  A larger pipe and more height should help.

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Almost all problems with low volume flue updraft can be fixed by going straight up with no elbows, going to a larger diameter and/or going taller.  Being in the wind shadow of nearby buildings, or over-topped by trees makes it harder to establish a draft as well.  Sometimes with very tall stacks or cold days you have to preheat the stack by burning a few sheets of newspaper inside the opening.

 

Exact same problems and solutions arrived at during the wood stove revival of the mid 1970's. ***

 

 

 

***(Whadda ya mean ancient history??? I was THERE, son!!!)

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Greetings 2ball,

 

From what I can see on your side draft I agree with John and Josh on the size of the stack.  10 inches will do but 12 would be better.. Also your opening at the fire pot is way to big.. Do some research on side drafts and suggested opening size ...  To give it a try a temp blocker of 2/3 the size would be a good start...  I hope this helps..

 

Forge on and make beautiful things

Jim

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Jim's spot on; first thing I said to myself when I saw the picture was "that opening will never work right with that pipe size!"  The opening should be smaller in sq units than the pipe is.  Then I read the post.

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As stated by others, your need to move from a 6 inch chimney to a 10 inch (minimum) chimney. There is just not enough room for the smoke AND the air to move through a 6 inch opening.

 

Your hood opening should be the same size or smaller than the 10 inch chimney. 10 inch diameter would be in quick numbers a 10 x 10 opening or 100 square inches.

 

Put a couple of sheets of newspaper on fire and st the opening of the hood, or inside, to get the air to flowing UP the chimney be fore you build a fire. Add a third sheet at the same time you light the fire.

 

This should fix all but one of your problems. Did you remember to cut the opening in the TOP of the hood larger?  You MUST have the opening from the hood to the chimney as large as the chimney, otherwise you choke the air down and it will not move. DO NOT ask how I know this, just take my word for it. (grin)

 

If you have a prevailing wind from say the side of the hood opening, simply put a sheet of metal up to block the wind when it blows. I added a 4 inch wide 7 shape piece of metal to my hood to form a roof and a wall to block the wind on my hood. It was maybe 2 inches from the top of the table so I could still use long stock if needed.

 

Please let us know what you finally decide and how it works for you.

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Double wall will do you best as well as a little hood protruding over the fire to coax it in the right direction. I don't prime mine because it has a good enough draft that it scatters ash all over the place. Prime with a blowtorch or something.

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Double wall will do you best. 

 

Do you have any references to back up the double wall is better than single wall in a chimney used for a forge?

 

 

I don't prime mine because it has a good enough draft that it scatters ash all over the place. Prime with a blowtorch or something.

 

Where do the ashes come from?  

 

You do not prime your chimney but then say prime with a blowtorch or something. Is this a conflicting statement?

 

Just trying to figure out you post. Please explain.

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Yeah it was a bit confusing. I did a test of double vs single wall, double wall worked much better. Same diameter, height etc. I don't prime with newspaper, as it gets sucked up and throws ashes, so I prime with a blowtorch,

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