Air flow

[Julia Freeman 0]

I notice a lot of people are using hair driers or similar to pump air into their forges. Before I go out and buy one, I was wondering if anyone would be able to give some sort of indication of how much air flow you need to be putting into a small charcoal forge? Can you have too much air flow?

 

Thanks

 

J

[Connor LogAn 0]

you most certainly can have too much air. with to much air moving too fast, your charcoal will burn up faster and more than likely melt or burn your metal if the coals manage to stay in the forge that long. a hair dryer is a good option but its a little noisy, i used a squirrel cage blower from an ac unit with a dimmer switch for a light fixture wired into it, it worked better than anything else i tried and was almost silent. good luck to ya!

[Julia Freeman 0]

you most certainly can have too much air. with to much air moving too fast, your charcoal will burn up faster and more than likely melt or burn your metal if the coals manage to stay in the forge that long. a hair dryer is a good option but its a little noisy, i used a squirrel cage blower from an ac unit with a dimmer switch for a light fixture wired into it, it worked better than anything else i tried and was almost silent. good luck to ya!

 

I found a blower that might do the job, it's supposedly rated at 80cu ft a minute at max. Is this too much or two little?

 

Thanks

 

J

[Doug Lester 75]

WAY too much but you might get by with it if you rig it with a choke plate to cut the air flow. In the last charcoal forge that I built; which was built in a 2 1/2 gallon bucket, about 10 liters to you; I use a large bellows type foot pump designed to inflate rafts. The bad thing about it was that it was single action. I don't know if you can find a hand cranked centrifugal blower in the UK but you might look. You could also look and see if you can find a pattern to build a large hand bellows. Functional antique blacksmith's bellows are going to be collector's items and go for collector's prices but you might give a look too.

 

Doug

[Danocon 6]

I notice a lot of people are using hair driers or similar to pump air into their forges. Before I go out and buy one, I was wondering if anyone would be able to give some sort of indication of how much air flow you need to be putting into a small charcoal forge? Can you have too much air flow?

 

Thanks

 

J

 

Julia,

 

See this thread about air flow. May be more than you want to know. Plus I got this out of it

 

[Stephen Olivo 0]

There are many blowers out there that will do the job and very well. You will almost always want a setup where you can choke off the amount of air being blown through it, so a blower that is overly strong is perfect for what you need. A blower from an oil furnace works really well with the oil part removed. A cheep made one is a japanese or chinese box bellow. I made one from scrounged scraps for the low low price of 4 bucks. It is always better to have more air than you need than trying to get just the right amount. You can always decrease it with a butterfly valve or a sliding valve. One thing to think of is how much pressure you need for it to effectively blow through the fuel. Some squirrel cage blowers don't have the pressure necessary and you will always bee fighting it. Look for one with the longest fins possible, you will see long fins in the champion cast iron hand cranked blowers that are well known here in the states for blacksmithing. Now if you are using it for forced air for a gas forge squirrel cages with short fins will work well because it isn't trying to blow through solid fuel. I personally use an old oil furnace blower that I rewired with a butterfly valve and only use it all the way open when forge welding large items and heating up large pieces of steel, but because of the small fins I have to be careful not to stack up the fire to high or it wont work as well. I also love my box bellows for the control it gives me in heating pieces and the pressure. In the end it depends on what your requirements are and what forge your running.

[Jens M. Strassegger 0]

A vacuume cleaner mounted in reverse with a dimmer on it works great imo. Doesn´t even need to be one of the big ones. Though they, like the hairdryers make a lot of noice. But nothing a few blankets or similar cant handle.

[Arno Visser 0]

Hi Julia,

 

Dan's way is really great. I have used his post to make a box-bellows myself. (Thanks for publishing your work like this Dan...)

It has taken me some time to finish it, but that is because I have the tendency to over-engineer everything...

 

But it works great. You can really control your air-flow with it. And a big plus......you're not in the noise of an electric fan.

Okay.....you don't have your hands free when you're heating up your piece, but centuries of blacksmiths have been working like this. It also takes a bit more space than an electric fan. So, when you have a small workspace like me.......but for me that sacrifice is well worth it.

 

Arno