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I Forge Iron

Blower for an air curtain?


Ed Caffrey

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Hi All!

I'm looking for suggestions for a blower that will hold up for use as an air curtain blower for the front of my gas forge. I've rigged up a couple of old forge blowers over the years with electric motors, but using them in an application with minimum restriction quickly burns up the motors.
My most recent "burn out" was with an electric forge blower (like the ones on the Buffalo forges with a reostat controller), that had been fitted with a 1/4hp motor. I suppose I could go to a 1/2hp motor, but I suspect the same thing will happen.
The way I have my air curtain set up is with the blower mounted near the floor, attahced to the table which supports my forges. From there is runs into 3" "drain" pipe and then is necked down into a 3" X 1" piece of steel tubing with a 5/16" slit down the long, narrow side which is mounted about 4" in front of the forge opening in a manner to blow the forge exhaust up into the hood.
Any thoughts or suggestions for a blower?
I've checked the 400CFM models at The Blacksmith's Depot, but I'm just not sure that would be enough air for the application.......but then again I'm just guessing.

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Thanks for the Welcome!
I've tried the small "squirrel cage" blowers.....they just don't have enough umph. With the heat the the forge puts out, mounting the blower on, or right next to the forge isn't an option. I suspect that I just wind up purchasing a new 1/2hp motor for the existing blower, and maybe rework the plumbing to create a bit of restriction. After studying the probelm, and asking some motor related questions, I discovered that when a motor is used in a blower application, any wide open (not restricted) flow is very tough on the motors and often winds up causing and over amperage situation, which in turn burns the run windings out. And here I was thinking just the opposite. Learn something new every day!

Thanks for the input....nothing like probelm solving to push a person to new levels! :idea:

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You're right that most blowers do need some static pressure to work properly.

Squirrel cages are designed to move air at relatively low pressures but high velocity - hence their use in HVAC and other air moving apps. Centrifugal blowers typically move air at lower overall cfm but higher pressure - which is why coal forges work better with old "paddle" fans. (In other words, a 400 cfm hand cranked centrifugal blower will always push air thru a coke pile better than a 400 cfm electric squirrel cage).

You could mount a piece of 3 inch pipe under the forge door after milling a 1/4" wide slot across the door width. That coupled with some 3" flex pipe to your big blower should make quite an air curtain.

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