From time to time I find I need to heat a bit of metal up rather more thoroughly than I can manage with a blowtorch. Being an adventurous sort I thought I'd make a tiny hearth, probably similar to this barbecue
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only with a smaller bottle and perhaps vertical instead. I can arrange some sort of blower without trouble using one of several redundant vacuum cleaners lying about.
What I need to know is what do I fuel it with, and from where do I get it?
I'm only looking to raise bits of steel to a heat where I can bend them more easily than cold. I'd like to keep smoke to a minimum as I get on well with the neighbours and would like to keep it that way - not that I'll be using it often but every bit helps.
Do a google search for "naturally aspirated burner". Lots of blowerless designs out there, up to being able to melt iron for casting. Lots of heat! (Nothing wrong with blown forges, but they do need a plug-in)
Most of the designs are propane fired, some natural gas.
Would make a nice quiet stand-alone rig that did not have to be plugged in.
I've been playing with the idea of converting an old BBQ to a melting furnace, to do a little bit of casting.
Lot's of info online on gas forges. Better insulating material equals more heat/less fuel burnt. You can make a damn fine forge without getting tied in knots over getting the last degree of efficiency out of the burner too.
For occasional use (how occasional?) a hole in the ground filled with charcoal (natural lump not briquettes) and a pipe on the end of an old hair drier works. Or lining any suitable container with wood ash, dirt, cheap kitty litter or any number of other materials works. If you just need enough heat to bend steel a blower may not be necessary even with solid fuel. There are a few blueprints on iforgeiron.com for building forges using various materials and at various costs.
Actually, for occasional use, even briquettes would probably work. A shop vac running on a router speed control might be pretty sweet, or set up your pipe connection so you can dump some of your excess air pressure and not launch ash everywhere.
Another option is to scare up some insulating firebrick (like from a pottery or furnace repair place) and fire it either with your existing torch or something like a weed burner. The enclosure will allow you to get the metal hotter quicker than in the open air... --Glenn Lyford
When Guy King put fingers to keys it was 8/25/07 2:50 PM...
Got tin-snips and a sharp strong thing? (think K-Bar combat knife)
Take two coffee cans the same size.
On the first can make eight cuts around the top edge, down an inch or so. At the bottom of one side, stab a hole in it, stretch the hole to about an inch and a half in diameter.
On the second can, stab the bottom full of holes. Something that makes a
3/8" to 1/2" hole is best.
Stuff the second can bottom-first into the top of the first can.
Put this setup on the ground.
Reverse the hose on a vacuum cleaner, lay the 'nozzle' on the ground and point it at the bottom hole of the first can. From about two feet away. Use a brick or somesuch to hold it in place.
Put a wad or two of newspaper in the upper can, put charcoal briquettes on top of that. stuff one square of newspaper through the bottom hole.
Light that bottom sheet.
Turn on the vacuum cleaner.
Adjust the air by changing how directly the nozzle is pointed at the hole.
When you have to get close to the fire, step in the way of the air-blast.
Depending on how far from the end you want to bend the thing that you're bending, you might cut notches in the top edge of the second (top) can.
One HOT place. Cheap, fast and fairly efficient. Will it last forever? No. Considering it takes maybe 15 minutes to make and maybe a buck to run, who cares?
I used to use such a rig to melt aluminum in the parking space next to my apartment.
- CW
Oh yeah, be careful when stabbing cans. And don't breath the smoke. Especially while the paint is burning off.
When Luke M put fingers to keys it was 9/10/07 7:41 PM...
When I melted aluminum (that's what I used this rig for) I would load it up and maybe have to add a few briquettes before I had a melt.
How much will you use? depends entirely on how much air you pump in and how long you run it. A smallish bag of briquettes should get you an hour or more.
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