blowers

[Ed Thomas]

Another hint for scroungers...

You can buy 3" flex pipe to go from the fire pot to the blower pictured above from Centaur Forge and others. It is several $$$ per foot.

Or you can dumpster dive wherever tractor trailer maintenance is done. The flex hose from the exhaust is 3" and usually stainless steel. I think you can buy it new, but I'm not sure what fun there is in that.

[HWooldridge]

Ed brings up a couple of good points I neglected to mention.

Stainless flex tubing is great but aluminum heater duct as found at Lowe's or Home Depot also works well. One downfall is that moisture which might accumulate in the bottom of any bends can combine with coal dust and eat a hole in the Al in short notice. Another problem is that this type of material is very soft and easy to poke a hole thru. Other than that, it conducts air just fine.

More good advice is Ed's note on speed control. It is far better with an electric blower to regulate with a damper or air dump than to mess with the speed. I learned this lesson when I was able to acquire a factory Buffalo forge with electric blower and rheostat. This forge (which I still use daily) came from an old Air Force surplus sale and had seen little or no use. I was fortunate to be able to see how the factory put one together - all the way from the stock rests to the half-hood. It was readily apparent that even on the lowest setting, the fan would outmuscle the fire in seconds. I burned up a lot of material until it finally dawned on me to leave the fan on and just adjust the air gate. The rheostat had specific "clicks" so I believe it was the factory's intent to operate in this fashion. For my single dedicated forge, I never use anything above the lowest speed setting but it is clear the blower will run multiple forges, so I'd bet lunch that Buffalo made it so the shop foreman could turn it on in the morning and have the workers control their fires as required.

[RBrown]

I have used a couple of electric blowers that i have riged up but use a hand crank now and perfer it. dont have to have wire any thing up and i have better control than with the electrics. iv got a champ 25 a mohawk (think 40) and a champion 400 i use the 25 all the time and the other 2 are spair.

[Leah]

While we are on the subject of blowers, answer a question for me. I have been told that, on a blower with a rheostat, you should let it come up to full speed on high then turn it down to the speed you need. Is there any truth to this and, if so, why?

[HWooldridge]

Leah,

A rheostat reduces voltage thru some sort of resistance circuitry. A straight AC motor without brushes needs to have close to full voltage to start. In other words, a 110v AC shaded pole motor with little basic load may start down to about 75 volts or thereabouts. I'm not talking about capacitor start motors or others under load - just direct drive fans like we would use on a forge. However, they will eventually reach a stall point where they won't turn and in reality, a squirrel cage AC motor is essentially either on or off, because the little blades on the blower cage don't catch much air when spinning slowly so you are back to my earlier comments in this thread about pushing oxygen thru a mass of fuel.

The advice you've heard to begin at full speed is so the fan will start, then you can turn it down to a certain degree, but the only thing you can have almost infinite control with is an AC/DC motor that has brushes. Most of the old electric blacksmith blowers are this latter type and will continue to rotate with very low voltage so there is always a breath of air going.

I believe it is best to install your electric blower with an on/off switch then put your air gate before the firepot. Turn the fan on full speed and control the air by choking the path (or the inlet - either works). In this way, you get the maximum amount of pressure the fan can deliver, but the volume is controlled so the fire doesn't get out of control.

[Leah]

Thanks, that explains some of the wierd things my blower does sometimes.

[Ed Thomas]

RBrown: If you prefer a handcrank blower then the electric blowers you rigged up were probably either rigged inadequately or were themselves inadequate. As Hollis and I pointed out, to get control of the air you need some good steady pressure, good volume and an air controlling gate. I've had both slide gates and butterfly gates. They are both fine, but you have to have good oomph and then regulate that.

For a very long time, I felt the same way you said, and even posted publicly that effect. I like the way you can come up to welding heat and gently feather in the last bit of air to get exactly the temp you want. A good manual blower is a treat to use. At one point I even installed a 'Y' connector with a gate so I could select either an electric blower or a manual blower depending on my mood. When I realized the manual blower was just collecting dust, I finally removed it. Now the manual blowers are used only for demos and group events needing several forges.

One problem is that while you are cranking, you can't forge. With an electric blower, you can have things heating while you are hammering. If you really want to become a professional as you said, this will start to become more important.

Another disadvantage of the manual blower is material size. When you move up to larger stock, you can spend a lot of energy and time cranking away trying to get up to heat. This is especially true if you use a power hammer. You can always get a bigger electric blower... you can't always go get a bigger arm.

[elkdoc]

I sucked it up and bought the med. sized blower from Kayne and Son's. I LOVE this little blower. Way more air than I'll ever need. I hooked it up with a straight shot to the side of my firepot with a sliding air gate inline to control air flow.

Works great!

[ThomasPowers]

A nice trick I learned from SOFA was to rig the electric blower with a foot switch---so it's only on when you are standing on it. Saves a lot of coal and stock as you are less like;ly to "forget" work in the fire. They also have a switch for on all the time for when you are needing a welding or other big fire. They also have an airgate to control the ammount of air to the fire when the blower is running.

Thomas