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I Forge Iron

is my hood to tall ?


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To answer you question, does smoke get into the room? Try opening a door or window to let an equal amount of air in that goes up the chimney. Go outside and look at the amount of smoke coming out of the chimney. That is the amount of air you need to bring into the room to replace what went up the chimney.

If you still get smoke, lay some metal up against the end first, then in front of the hood from the top of the hood down. You may want to close up the sides on the front some. Once you get no more smoke, problem solved.

You do have a chimney attached to the hood don't you? What size / diameter?

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Do not skrimp out on the diameter of the pipe! Or the height of the pipe. The exit of the pipe must be above the roof line. The taller the pipe the more velocity it works, but there are limits (laaws of physics).

Many old school people always had their chimneys 2 feet above the peaks in their roof. So, there must be something to that.




Carry on

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I found this 'cone' at least 35 years ago in a junkyard and paid $15 for it. It's been through more moves than I care to remember and it's always functioned just fine with a 10'' pipe. I've thought about upgrading to a fancy side draft, but it ain't broke......Hoods can be used in a couple of ways that I wouldn't try with a SD, that is if I have a small painting project or acid etch to do I can do it under my hood (cold of course) and the fumes are wisked away no problem, otherwise they get done outside. 2' above the roof is minium and may be more as per code. Never scrimp on the length, but if it's too long it will tend to cool the smoke too much which can cause drawing problems.

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macbruce that looks like a cne I made well over 30 yrs ago.I am sure it is not tho.I used the cone off of an OLD belt drive feed grinder.it had a 6" pipe
I unbolted the dust separator on top,flipped it over and hung it in the shop.no back or sides.just hanging above the forge

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  • 1 month later...

Well that's bad news, I have been watching your shop build and was hoping for better results for you.
If that taller pipe doesn't do the trick for you close off about 25% of the bottom of that pipe with a ( temporary ) piece of sheet metal. Just to try and get some draw going. If it doesn't help you are out about five minutes of work and I will catch a lot of flak from my friends here at IFI. Oh but if it works........

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Our shop is small and because of a number of things the diameter of the pipe was limited to 10 inches.... I think. It has been a number of years so we ended up installing a draft inducer in the pipe where it went through the second floor roof and there is literally no smoke in the shop. After the fire is hot we many times turn the fan off and it will draft ok but if it's windy the fan just keeps running.

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Man you never ask that question, its like a lady asking "do these pants make me look fat?"  :)

 

I use triple wall 8" id, on a side draft and don't have issues, draws well. BUT that is with triple wall all fuel stack that keeps those gasses hot till the exit.

I use a small 7" stack on my demo trailer, and it is a intergral side draft, and about 8' tall. Sucks up the smoke and it exits above head height so me and the viewers don't have to eat smoke:)

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If you already have the wood stove going, that has probably already got the draft coming down the forge flue. Try lighting the forge first.

 

But it works good once it gets going? Preheat the forge flue.Try lighting a piece of newspaper and putting it up the pipe before you light the forge.

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I always lite the wood stove first it gives me the coles I need to light the forge fire. So with the shop being hot that makes the Forge flue backdraft ? And I've always balled up newspaper and put it in the flue Per Glens advice . It's only coming out toward the verry edges of the forge hood . I'm almost certain if I lower it some it will draw just fine....

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Just a thought, is your shop closed up very tight with winter being here etc? I know if our furnace is running and I open a outside door I will get a blast of warm air as the furnace is an ols system and uses outside air source. If the forge is running in a tight room it might be possible it isn't having a free flow of air to the outside. Again just a thought.

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We installed a Tjurland draft inducer..... if memory serves me right in the stack within the second story. It runs on 110v and we use it to start the draft. Once all is hot and working you can shut the fan off and it all works quite well. The box we built to house the fan at the roof penetration area has a temperature sensor in it so we can tell how the stack and box are at the roof. The readout for the sensor, blower control and fan control are all at the forge on the first floor.

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