hot or cold air, forge project

hi,

im gonna be building a very basic forge soon, and i wonder what will give a better heat, hot or cold air

heres a simple design of my forge.

advice is welcomed

Originally Posted by jimmy shoes hi, im gonna be building a very basic forge soon, and i wonder what will give a better heat, hot or cold air heres a simple design of my forge. advice is welcomed

what u putting in it coke ?? the hairdriers a bit tame innit use sumthing a bit more substantial something u can regulate the air suply with cold air best

what are u making with it??

Cold air, you theoritically get a more dense charge of air, will it make a diference? who knows.

hair dryer? is that beefy enough? my neighbour uses a vaccuum cleaner to feed her forge with good results.

Chunko'.

Originally Posted by chunkolini Cold air, you theoritically get a more dense charge of air, will it make a diference? who knows. hair dryer? is that beefy enough? my neighbour uses a vaccuum cleaner to feed her forge with good results. Chunko'.

not suprised a hoover on blow would melt iron in coke

i thought i'd just put BBG coal in it.

well i saw a video on youtube of a guy making a knife out of an old file, so seems that i got a few old files i thought i'd give it a shot. plus if i get any future projects where i need alot of heat i can use the forge.

Originally Posted by jimmy shoes i thought i'd just put BBG coal in it. well i saw a video on youtube of a guy making a knife out of an old file, so seems that i got a few old files i thought i'd give it a shot. plus if i get any future projects where i need alot of heat i can use the forge.

cokes best clean and hot

Yep-i would agree with the coke idea. Burns clean and is hot. The ash is very fine & dusty when cleaning out though-just use a simple mask.

The idea that Chunkolini mentioned about a vacuum sounds good.

Air volume is more important than temperature, plenty of industrial size forges run on cold air, just with MUCH more airflow than a hairdryer. Also you'll pay for the power to heat the air (most of the hairdryer's power consumption) which is a waste of money.

You need a throttle on the air supply too, for regulating flow and to shut it down when you are working on the metal in between heats. Just put a sliding 'gate' in the pipe, with a handle so you can slide it across. You'll burn through a LOT of fuel otherwise - when my forge is on full pelt you can literally see the coke being used up - almost like pouring liquid into the middle of the fire.

BBQ fuel is useless - too much ash in it, too sulphurous and won't burn hot enough. Plus the lumps are too big, you need to be able to push your workpiece between the lumps, you can't do that if they are too big - always ends up hitting one and getting stuck. Look for coke 'beans', or anthracite beans, or forge coke. Corrals sell it - google them to find a depot.

Run a straight air pipe - easier to make, better flow. make sure you give yourself a way of getting the crap out of the air pipe that falls in (without killing the fire). Bottom blast forges (which is what you've drawn) usually have a gate underneath to release the 'clinkers' (crap) that build up.

You can't really go wrong, just experiment, the worst that can happen is a hole burns through something it shouldn't. Good luck, Al.

The last place I worked had a forge which was blown with a 'Henry' vacuum cleaner. The flexible hose was connected to a steel air supply pipe which ran through a water tank and then into the back of the forge base. The blacksmith used a mixture of coal and slack on the fire.