I have decided to fire my coal forge using an electric blower. To get it adjustable, I've considered two methods

1) Building something like this; or
2) Having a sliding cover over my blower's intake that restricts the air flow.

Does anyone know if the first thing will actually work? It says it's designed for an electric motor, but I'm far from being an electrical engineer.

Are there any downsides to physically restricting air intake?

If the motor doesn't have a start winding then you should be able to use a rheostat to control the speed. They a fairly inexpensive at Lowe's or Home Depot. You could restrict the intake or you can use a blast gate between the blower and forge which is what i have on my forge. McMaster-Carr has them

When it comes to electronics I'm a first class weldor so I don't know what the diagram says. However, I do know the electronic cycle controlers work fine with induction motors but power reduces with RPM.

Restricting intake works fine as long as the motor doesn't rely on blower air for cooling.

A bypass in the outlet is another if more complex option that allows plenty of air for the motor. Bypassed air can be directed up the flue to increase draft.

Frosty

Why not put an air gate in the line, it won't hurt a thing and is simple to adjust.
Travis

I use an air gate that I bought from the internet. Simple and works well.

You might also consider adding a spring loaded foot switch, so that the blower is shut off when you step away from the forge. After you forget to shut off the air and burn up some steel, you'll find it handy. I made one from the foot switch that came off an old sewing machine.

Steve

I just use a butterfly valve I made to go in the pipe, it looks like the manual choke on a carbuerator.

When you buy a CF PB50 blower you get with it a speed control which is a heavy duty light dimmer switch normally used to dim lights. Most folks that use that blower only use the speed control, infrequently, to slow down the speed of the motor, when possible, to keep the noise of the motor down to a more comfortable level. The electronic speed controller works, but the motor reacts too slowly for most folks. Everyone I know uses an additional aluminum & galvanized sliding gate in the output tube as a main air controller. CF sells sliding gates for around $12 (been awhile since I checked the price). They can also be purchased from woodworking supply stores as a damper for sawdust collection systems. Maybe they can be purchased from the local furnace supply outlet. I made a sliding gate for my permanent forge. I put the CF sliding gate on my portable forge. I'd never make another one considering the price of the purchased sliding gate and since it works exceedingly well. I have a pivoting plate that covers the input of the fan on my gas forge. It works well also, at least for that purpose, but wouldn't work well for my coal forge as the fan is to low and inconvenient to reach. The sliding gate on my coal forge works off a push pull rod right under my forge table next to the firepot. It is handy.

I suggested an air gate but any kind of valve will work. I set mine and very seldom move it. I also use a foot control, saves a lot of coal.
Travis

Thomas Powers once mentioned, that it is better and easier on the blower motor to restrict the amount of air going into the blower, rather than restrict the air coming out of the blower. I have my forge setup so, i set the blower at whatever level of airflow I need, then have an ON/OFF air dump valve, on when heating off when you step over to the anvil to hammer.

Yo can make a sliding air gate very simply: IronFlower Forge - Construction

Although this on is implemented on the output (blow) side of the blower, there is nothing to stop you doing it on the intake (suck) side.

Something I've been interested in but not yet needed is a blower muffler. I read this in The Artist Blacksmith by Peter Parker-Pearson; build a box from boards (lower density is probably best) and line it with something like rockwool (quite loose fibreglass insulation). Put the blower inside and have the intake hole reflexed; rather than just a hole, build an extra insulated enclosure at 90 degrees to the axis of the hole. With this setup you can reduce noise, easily add an intake filter and, crucially for this thread, add an intake control gate, irresepective of how your blower is built.

Edited May 17, 200818 yr by matt87
Pur speelin an grammare

My blower is so quiet, you barely know it is on at all. It's the one from BS depot

Blacksmiths Depot

Dutchmancreek said:

I use an air gate that I bought from CF. Simple and works well.

You might also consider adding a spring loaded foot switch, so that the blower is shut off when you step away from the forge. After you forget to shut off the air and burn up some steel, you'll find it handy. I made one from the foot switch that came off an old sewing machine.

Steve

 

Thats a great Idea! ANY PICTURES? Thanks,Chris

 

Yo can make a sliding air gate very simply: IronFlower Forge - Construction

Although this on is implemented on the output (blow) side of the blower, there is nothing to stop you doing it on the intake (suck) side.

Something I've been interested in but not yet needed is a blower muffler. I read this in The Artist Blacksmith by Peter Parker-Pearson; build a box from boards (lower density is probably best) and line it with something like rockwool (quite loose fibreglass insulation). Put the blower inside and have the intake hole reflexed; rather than just a hole, build an extra insulated enclosure at 90 degrees to the axis of the hole. With this setup you can reduce noise, easily add an intake filter and, crucially for this thread, add an intake control gate, irresepective of how your blower is built.

Hi,
Matt, i'v been looking foor building plans for a good sliding gate, but I don't lake the idea of making it in wood...
does annybody have anny plans for one in anny metal?

Try contacting John B. He build most of the English water cooled forges at Westpoint Forge; they use a metal sliding air gate at the back, controlled by a horizontally pivoting level at each side.

Hi Eyrian, a simple restriction device on the air inlet side like an adjustable flap will work fine. Take note of Frosty's advice though 'as long as the motor doesn't rely on blower air for cooling'. I've used such a system for years at home and at classes I run, no problems. I'll get out to the shed later today and take a photo of my setup and you'll get the idea. Your blower maybe different to mine. I'll also post the details of the blower because I believe there will be a US verson available. Cheers

Two Toes?

A dingo eight the rest?

Sorry, couldn't resist.

Frosty

Thanks Frosty,

Maybe it was Frostbite!
No the truth is they reckon I'm too slow to be a three toed sloth so therefore I must have only two toes.
Cheers.

Another idea on air control is if you are using a bottom blast forge with air entering into the side of the ash dump area, if you have an ash dump plate that is pivoted so it crosses the base like a shear blade, as opposed to dropping down, Then by moving the plate across in small increments, then the amount of blast can be controlled as you can balance the amount of air going to the forge tuyere with amount of air being expelled from the exposed ash dump.

Just don't have anything combustible around the base of the forge

This is not a method I would use personally, but it is effective

I just use a dimmer switch on my blower on the brick forge. It works fine. I don't have one on the latest of the portable ones so if I want to reduce the blast I just open up the ash dump- gets rid of ash and splits the flow.

If you want a good picture of an air gate look at Vaughans new on line catalogue. It is very well illustrated. Vaughans (Hope Works) - For all your Blacksmith and Foundry needs. and follow the link to the catalogue.

I use a butterfly valve, on my bellows to control the air and the same thing on my lectric blower on the forge at the shop.

Side blown nozzle with built in butterfly valve for bellows.

Open


Closed

Hi Eyrian, As I promised here's the photos of my setup with the air gate on the inlet side of the blower.
The old blower I've been using for about 6 years with no problems and it's very quiet and hardly gets any warmer than about 75-80 degrees F after a full day.
I've included photos of a new blower so you can see what it's like inside and it's label, the blower casing is about 5" inches in diameter, the ruler is a 12".
The model I use is a Fasco EB80.I've checked the Fasco USA site and I couldn't find it so its probably an Australia only model. However it is an 80cfm single phase centrifugal blower and there some of them on the Fasco USA site they look a little different but I reckon they're basically the same blower. A US supplier sells this model for $66.00 (That's about half what I pay in Australia for the EB80). Now to clarify further the air delivery (tuyere)system I use is a modified German system with a grate (the coals burn on top of the grate) and I use only coke or charcoal as a fuel, not coal.
There is little restriction to the air flow from the blower and the air coming out of the grate is fairly low pressure but at good volume. If you are using a more traditional single outlet tuyere in your forge this may alter your blower requirements from mine. I'm sure Fasco will have something to suit as they manufacture blowers and motors for just about anything and are OEM suppliers for many manufacturers.
I hope this helps, and the photos work,its my first effort at an upload.

Cheers.

Edited May 21, 200818 yr by Bruce Beamish
Spelling and Grammar corrections

Surplus Center

ther,s a difference between velocity and volume
u need to be able to controll both
harley

I think it was Bob Patrick or maybe Frank Turley that stated at one of our Conferences that you only need 2 ounces of pressure to make a forge firepot work well.

Both Irnsrgn and Larry make valid points. I was just trying to point out that the system I use is different and what works for me may not work with a traditional setup, I've not used these blowers with a single outlet tuyere either bottom or side blast. My handcranked Lancaster blower that I use on my portable demo forge (with the same grate system) is capable of a lot more pressure at the outlet but when the forge is burning well I hardly have the handle turning over.
Cheers.