Ok so I got all of the parts cut out for my forge today. The fire pot is four inches deep Eighteen
Inches long and fourteen inches wide. It is bottom fed and the ash/air pipe is six inches in diameter. The air pipe is three inches in diameter the firebox is one half inch thick. So we are talking a rather beefy design. Yes it's overkill but the materials were free so I can't argue. My question Is one of CFM or whatever common size metric is used for fans and bellows. This is to be my main daily use forge and I want to be able to use it for any size job I may decide to tackle. I had a forge with bellows and found a fairly high degree of control could be had but it's quite a bit of extra motion when working alone. Any suggestions on a squirrel fan size?

Most blowers were 250 to 400 cfm (e.g. the Champion 400) but squirrel cage blowers do not produce sufficient pressure to properly feed a solid fuel fire (although they can work on gas forges). That's why centrifugal fans with paddle blades are pretty much universal for coal, coke or charcoal; a double bellows also works well for the same reason. You will likely get a plethora of people claiming how well their Dayton squirrel cage works on their rivet forge but it will never be as good as a paddle fan.

Yeah I need to attain welding heat when I want it quick. How much can I expect a decent centrifugal fan to set me back?

Good used ones are still out there for sale. Local blacksmith groups, net listings, Ebay, etc.

https://www.blacksmithsdepot.com/page.php?theLocation=/Resources/Product/Forges_and_Parts/blowers.xml/

Phil

Thanks Phil

I got a squirrel cage blower from a residential HVAC company for free. I yanked it out of a scrap furnace he had replaced. It's a universal motor so you can slow it down and control it with a rheostat. It adjusts from barely blowing to nearly blasting the coal out of the pot. And I couldn't beat the price. Drawback is it's bulky but so is the forge.

E-bay seems to have "belt -driven" blowers fairly often, and they go cheap compared to hand crank jobbers. Should be pretty easy to cobble one up to an electric motor with some type of pulley/ belt system.

E-bay link to one I found

If you have access to a heating company the exhaust blower from a gas furnace seems to work well. The one I had turned out to have bad bearings but I had a heck of a fire going till the motor overheated. I am getting another one this week from a furnace that is supposed to come out today.

All 90% furnaces have them and I am told they all have them in the last 10 or 12 years.

Two sources for good forge blowers are leaf blowers and the type used to inflate those air-filled playhouses that are commonly rented for children's parties. Northern Tool sells one of the latter for $140 that puts out 800 cfm at 6" static pressure...plenty for any forge you'll see in an average shop. You could run that one at full speed and use a damper to control blast.

NT also sells a little electric leaf blower for $25 and I'm tempted to try one just to see how it works on a gas forge.

I got a line on a free furnace blower going to get it this weekend. I will have to do a bit of duct work but that's no issue I will post some pics when I get done.

I'm setting mine up with a blower and motor from a clothes dryer. I haven't plumbed to my satisfaction yet, so I'll post on it's performance soon.