I've been forging for about a year, and have gone through some very old, very used fans. My current set up is a dayton squirrel cage fan (not sure of the model number) that I can control the cfm on easily. My issue with it is after a few hours, it starts to overheat, sometimes shutting off completely. I'm looking for a new fan to use, and haven't been able to find if an inline duct fan would be usable. I'm a young father of twins, so inexpensive is better.

 

Here's what I'm considering: http://www.lowes.com/pd_223430-1061-DB200_0__?productId=3199249&Ntt=inline+duct+fan&pl=1&currentURL=%3FNtt%3Dinline%2Bduct%2Bfan&facetInfo=

 

My forge is an old truck rim (about 0.5" thick steel) with an elbowed 1.5" pipe expanded out to a 6" intake. The original fan, which was out of an old refridgerator/freezer, didn't have enough airflow. I went to a blower from an oil heater, which died on me, then to the current setup. Any help would be appreciated.

 

Thanks

First how are you controling the air flow?  Redirecting the output is the best way, if you are restricting th eintake, they will over heat.  Using a fan speed control ( like used for ceiling fans) is another way to slow down the air

The fan i'm currently using has a flap over the intake (factory installed), so I'd have to say restricting. However, the maximum output is right where I need it when I'm working currently, so there isn't much flow control necessary.

hmm got me stumped as to why its over heating... the inline duct fan should be fine for air into the fire pot .

 

 Once I cheated and used an old one as exhaust fan before.  It worked, tho I wont recomend that use for them

Great! Thanks for the help.

If it is a largish squirrel cage fan it will be designed to operate correctly at higher ~500+ CFM flow rates but only with a very low back pressure. Forcing such a fan with a high output to run at full speed just to get the required flow through a narrow duct is severely restricting its output so that it will just end up spending most of its time running at full speed with its impeller cavitating ie stirring the same air round and round, which just heats up the air and will overheat the motor.

 

Many squirrel cage fans do not generate the pressure required to force air through small pipes plus a forge on the end of the pipe.  Many Inline duct fans also cannot generate much pressure so there is no guarantee that it will work either.

I've been using my squirrel cage mounted as you can see in this link for a year now without any problems.  When you redirect the air flow away from the tuyere the fan slows down, whereas if it's flush against the pipe it goes full blast.

 

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I've been using my squirrel cage mounted as you can see in this link for a year now without any problems.  When you redirect the air flow away from the tuyere the fan slows down, whereas if it's flush against the pipe it goes full blast.

 

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All of the squirrel cage fans in that thread look like they are appropriately sized (ie smallish)  to better match the needs of a forge.

It's just a guess but with a 6" diameter forge air intake it sounds like sarcat2012's fan is a bit bigger that these.

 

 

 

I used a 13 dollar bathroom vent fan for abut 6 months. It worked great and I never had a problem with it. The only reason I stopped using it is beause I got a hand crank blower.

Go centrifugal over axial. Axials are the ones that look like a propeller, and they can't  overcome much resistance.

I use a ventilation fan from a car, powered by a small battery charger (with an old battery as ballast). If you have a decent battery charger you probably won't need the battery.

A bathroom exhaust sounds like it'd be a winner. One of my company's suppliers does a small-ish one with a 60mm outlet for about $80. If I hadn't already had the car fan set-up< I'd have gone with that.