Tuyere size question

[NMcCartney]

I’m still new to doing this so I apologize if this is a recurring question (but I didn’t come across it on a search of the forum). I’m looking to change my forge from running on an electric blower to a bellows (or possibly hand crank blower) but I’m not sure how large the bellows would have to be to give a good air flow.

The tuyere is 3x3 inches. I’m currently using lump charcoal but am considering switching to coal in the future, but that’s not an immediate plan. My concern is that I’ll get a bellows made and end up finding out that the air flow isn’t strong enough to get the fire to a desired temp.

Any thoughts or suggestions are appreciated.

Also added a pic that hopefully loads to show exactly how its set up.

 

[JHCC]

Why do you want to change from electric to hand-powered?

[Steve Sells]

whoever wired that needs to be shot its not safe 

[CMS3900]

lol steve. Not everyone is going to run MC on their forge.

McCartney, a place to start would be to figure out what CFM your current blower is, which would give you a idea on how much air you need.

[ThomasPowers]

I never had trouble getting to welding temps with my home build double lunged bellows---it just takes up most of the pickup bed to transport.  I've used a Chinese Box Bellows that worked well and was MUCH more portable and I set up a Y1K forge at times using two homebuilt  single lung bellows based on Theophilus'  "Divers Arts" (circa 1120 CE)---the metal working ones not the organ ones; they work well but require a bellows thrall to be productive.

So build your bellows to produce the amount of air you need! That blower is probably producing many times the amount of air that charcoal needs and so matching CFM is a great waste of capacity. My double lunged bellows was based on a commercial version that I got the measurements from a museum, Late 19 century IIRC. I used heavily treated tarpaulin for the "leathers"  Stuff that was made for use as wind wings on oil drilling rigs. Worked great for over 20 years.  Biringuccio's "Pirotechnia", 1540 CE,  mentions cloth sided bellows IIRC.

(as to why: perhaps he forges at locations without electricity; or wants to have his kit a bit more accurate for a historic period, (note bottom blast forges are generally post medieval and coal only starting to be used in High to Late medieval times---Gies&Gies "Cathedral Forge and Waterwheel"  sometimes the SCA Laurel creeps out...)

You may find that using charcoal is much nicer once you get rid of the electric blower and adapt your firepot for charcoal instead of one for coal that you are using charcoal in.

[Charles R. Stevens]

Charcoal likes genial air and a side blast forge much more. Your fire pot looks deep enough but build a gate between the blower and tuyere and consider some kind of fence to hold extra fuel above the hearth. It will still be fuel hungry

[NMcCartney]

Thanks everyone for the quick replies.

One big reason I want to get away from electric is because currently I have to run an extension cord from my kitchen and across the backyard to the place I can forge safely, and we have no outside electrical sockets or power in the garage. So that becomes a problem, especially with kids and pets running around. 

As for the forge build; that’s what I got to work with, lol. I’m looking into getting a welder in the next few months so I can have some more versatility when it comes to modifying stuff but for now it is what it is.

I’ll start looking into the blower’s CFM though and see what I can figure out. Thanks everyone. =)

[Charles R. Stevens]

Their are other options, such as the simple sideblast forge (J(ust) A B(ox) O(f) D(irt) forge. Scrap wood and dirt.... no welding required. Then the monster you have will be ready for coal and a hand crank blower or bellows