Technical spec for forge blower.

[Mick]

Still gathering resources to construct my first forge. Can anyone help me with some tech specs for a blower for a charcoal forge.

Is there an optimum range for air flow volume and pressure,

This information will help me source a non forge specific blower, hopefully a very cheep one.

Thanks Mick

[Dave Leppo]

Air Pressures and Pipe Sizes for Forges Edited April 2, 2009 by steve sells
fix URL

[ThomasPowers]

Ahh Mick this reads an awful lot like: "I'm spec'ing an engine for my vehicle; can you tell me how much Hp it will need?

Of course I'm not going to tell you if it's a massive truck or a small city vehicle and I won't tell you if it will be used 12 hours a day hauling heavy stuff or only to get to the mailbox twice a week. But please tell me what I need!"

So how big, how much you going to use it and for what?

In general charcoal forges don't need much in the way of air, a regular blowdrier for hair usually puts out too much air for a small hobby forge. Charcoal seems to have less back pressure than a coal forge does.

[Frosty]

A little more than you need, then put a waste gate or choke plate in the system to tone it down to what you need at a given time.

Or were you looking for something specific?

Frosty

[Sam Thompson]

I used old hoovers to blow quite a big (side draught) forge for years. You can control the blast with a clamp on a bit of flexible pipe, this will give you an idea of the sort of air delivery you need for your forge.

[Mick]

OK so the minute I clicked the post thread button I realised I was probably asking 'how long is a piece of string'.

However I am developing a great faith in the clairvoyant skills of IFI members and their ability to provide enough clues to set me on the right path regardless of how badly I phrase my questions.

One day I may even post a thread consisting of just a question mark, ?, and I'm guessing it would still elicit, a bevy of well reasoned, informed and helpful replies, and hopefully as long as the bear does do-do in the woods, Frosty will be throwing in a measured dose of humor.

You guys are sensational.

I suffer from Blokes Disease :- It can't be that simple, I will have to find a complicated way to go about it. Big is good - bigger must be better. One of anything could never be enough. I know deep down I am probably trying to re-invent the wheel but I will forge ahead regardless.

There is no known cure but I try to manage the symptoms.

Thanks to you guys I now know that anything that will deliver air at 1.5 - 3 p.s.i. through the tuyere and grate is going to do the job. I don't need 25,000 pounds of jet thrust.

Mick

[Frosty]

Volume, you have to have enough volume within that pressure range.

For instance I can develop that range of psi with a syringe but couldn't do much forging with the fire it'd draft.

Oh yeah, FYI. Bears do it wherever they want. Fortunately that's usually the woods and not my front porch.

Frosty

[billp]

OK
Now I was looking for an answer to the question of how big of a blower do I need but still not sure if I have found it reading all your specs. I know, I know and yes a box of rocks and a bag of hammers may be smarter, BUT?

I have a fire pot 6" at the bottom 8" at the top with a 2" depth, home made, my blower will be about (including the 90 degree turn) 6" to 8" from the bottom of the fire pot.
OK, now I'm looking at 2 blowers; one has 60 cfm, .42 amp, 3,030 rpm, 1/25 hp. The other 148 cfm, 1.37 amp, 3160 rpm and 1/25 hp. both have adjustable air inlets, which is the better choose? There is only about $8.00 difference in the price but the smaller one has a round discharge while the other square. So for me the round is easier to rig up to the forge but I still want the best for the job not the easiest.

OR, to make matters worse are either of these blowers right or do I need something smaller or bigger?
See I am very new and know very little but slowly and surly I'm getting better.
If not asking to much Help!
Bil P

Edited April 4, 2009 by billp
to answer a piont made by Frosty about air inlets

[Frosty]

Ah! Finally enough particulars to reasonably expect a specific answer. I don't usually burn solid fuels and don't have a clue as to what my old champion elec blower puts out but it's a LOT and I put a gate on the intake to tone it down.

Not knowing for sure, I'd buy the higher capacity blower, it's easy to restrict or dump too much air but there's no way to get more than it will put out.

If the motor relies on the blower for cooling then you need to make a dump/waste gate so there's always a flow of air across the motor.

If the motor is independently cooled then you can make a simple damper gate across the intake to control air.

And I'm sure someone who actually knows will speak up soon.

Frosty