Forg-Cnstrctn-art - 4/28/02 "A Simple Portable Brake Drum Forge" by Master Magnus Malleus. Directions for building a simple forge and other information useful to the beginning blacksmith. NOTE: See also the files: blksm-forges-msg, blacksmithing-msg, blksm-anvils-msg, blksm-welding-msg, bellows-msg, bladesmithing-msg, Non-Ferrous-bib, casting-msg. ************************************************************************ NOTICE - This file is a collection of various messages having a common theme that I have collected from my reading of the various computer networks. Some messages date back to 1989, some may be as recent as yesterday. This file is part of a collection of files called Stefan's Florilegium. These files are available on the Internet at: http://www.florilegium.org I have done a limited amount of editing. Messages having to do with separate topics were sometimes split into different files and sometimes extraneous information was removed. For instance, the message IDs were removed to save space and remove clutter. The comments made in these messages are not necessarily my viewpoints. I make no claims as to the accuracy of the information given by the individual authors. Please respect the time and efforts of those who have written these messages. The copyright status of these messages is unclear at this time. If information is published from these messages, please give credit to the originator(s). Thank you, Mark S. Harris AKA: THLord Stefan li Rous Stefan at florilegium.org ************************************************************************ Date: Fri, 26 Apr 2002 08:18:02 -0400 From: rmhowe To: "- Stephan's Florilegium" Subject: Re: A Simple Portable Brake Drum Forge A Simple Portable Brake Drum Forge by Master Magnus Malleus The most basic forge can simply be a hole in the ground with a pipe (tuyere) supplying air from beneath or beside it. Or: An easily made portable forge can be had with some basic 2" pipe fittings, an electric blower, and a cast iron brake drum. I have had three forges in my time, a brake drum forge (actually my favorite), a very large commercial Buffalo forge, and a cast iron band saw brazing forge in which large tongs were heated to braze huge band saw blades together. I sold the Band saw brazing forge because it got too hot to be anywhere near. I traded the full size forge eight years ago when it became impossible for me to hammer much anymore, with a few other items to make a fair trade for a milling machine/lathe combination. To make an Simple Portable Brake Drum Forge you need: A brake drum from a car. Larger car sizes are preferable. (Truck brake drums are huge, deep, and have huge holes.) These are found at any scrap yard. Some fire clay, and some Hydraulic cement to mix it with 50/50, obtainable at a building supply place. Something to mix it in. A plastic bucket for example. Something to trowel it in with. (Plug your blower holes first.) or Some -soft- refractory brick to cut to fit the bottom of the forge. You can cut this stuff with a hacksaw. If your local brickyard/home supply place doesn't have it try a pottery supply store. You also need a set of -2"- (preferable) or 1 1/2" pipes: A pipe flange for the bottom of the brake drum, where the hole is. In my case I scrounged around and found an old cast iron gear to put over this. The center of the gear had a one inch hole in it and I drilled the outside of the gear with a number of 3/8" holes at an angle tapering to the center to create a focused air blast a few inches above the gear. This is where you obtain maximum heat. You could also use a cast iron drain plate or some holed stainless steel to help cover the hole in the bottom of the Brake drum over the 2" pipe, which is large enough to allow chunks of coal/coke/clinker to drop down it. Ordinary steel will burn through because of the carbon in it. Cast Iron won't burn easily and stainless would have to melt. To drill stainless steel you will need to buy or borrow a cobalt steel (some say C or M42) drill bit. Rest of pipes: 2 six inch long threaded pipe nipples to screw above and below a 'T' connector. The upper one screws into the flange. The lower one screw into the Pipe cap or oil drum cap. An oil drum cap to screw on the bottom of the bottom 6" nipple to function as a clean out. I used a piece of strap steel bolted to the cap with a counterweight to simply allow me to raise it with my foot to clean the pipe out. You could just stick a nail in the lock holes that are in these caps. If you can't find one you can simply use a pipe cap. You need a way to clean out the pipe either way. A foot long piece of pipe threaded at both ends. to screw horizontally into the 'T" fitting to connect it to the blower. Some bolts and nuts appropriate to what you are bolting through. A Drill and a few metal bits. A Piece of Sheet metal to make a blower cover out of. A little knob and screw. Most hardware stores have all of the above in stock. A blower: This can be a 120 volt electric blower with plug and in line switch (buy and install it in the hot side of the wire) or a 12 volt blower to hook up to your car battery with a set of alligator clamps. Or both interchangeably. In my case my initial blower had a square hole, I made a wooden block to fit the opening, screwed the block inside the square opening and drilled a hole I could thread the 1 foot long pipe into. (Alternately you could use a hair dryer, or a vacuum exhaust. They just aren't as controllable.) If you are going to be working on damp ground I recommend a three wire system hooked up to a portable GFCI or plug it to an in line GFCI, also known as a Ground Fault Circuit Interruptor. If you can't find a place to connect the green wire to on your blower, attach it to a bolt on the outside motor casing. This is so you won't get a fatal shock. If you don't know for sure what you are doing, ask an electrician or look in an electrical book. (I got my sophomore housing at college because my predecessor at the house electrocuted himself with a vacuum cord he'd dropped into a puddle he'd made washing his car mats. I am told that can be a slow way to go.) GFCI's can be had for as little as $10 or less. They only work on three wire grounded circuits with Black (hot)/ Green (Ground) / White (Neutral) wires. GFCI's cut the circuit before you can receive a fatal shock. This is what is required within six feet of water outlets in your house as well. Look in the kitchen and bathroom. They usually have a test and an on switch on them. Portable ones are $10-35. Hot black wires go to brass colored screws, White to the silver colored screw, green to the green screw or wire or to the bare wire without any insulation inside the wall box. (My wife could have easily died when someone hooked these up incorrectly and hot-wired a new stove case. She did get a shock.) If you are wiring in a GFCI wall box remember to cut the power at the main panel. Test to make sure it's off. A radio or light that is turned on will tell you when it is off if you don't have an electrical circuit tester. Northern http://www.northernstores.com/ and stove supply stores sell 120 volt blowers. So does American Scientific Supply or Surplus Supply usually. Look in the back of Popular Mechanics for Surplus Supply's address. or try this page for another. Bottom Left: http://www.73.com/a/0701.shtml See bottom of page of http://www.mscdirect.com/PDF.process?pdf=4179 for an idea of what I am referring to. Just smaller and cheaper. Can be had for $15 if you look around or scrounge your local scrap yard. Frequently ours has huge bins full of motors and fan motors. Blowers also exist within old air conditioners. These can be 120 or 240 volt in larger ones. (The problem with old air conditioners is that they also contain freon, and if you rupture a pipe getting one out you can blind yourself with the spray. I don't recommend this, but if you dig one out of one of these at the very least wear eye protection, with or without a face shield.) Getting one out can be difficult, so I recommend a different source. Call around. 12 volt blowers can be picked up at any auto scrap yard. They are used in the car heater system under the dash board. Alligator clamps may be had at Radio Shack or an auto supply place. Make sure you put the insulators back on their handles. Or put a lighter receptacle plug in instead. A blower's blast is simple to control by simply putting an egg shaped piece of metal over the intake hole with a small bolt in the small end of the egg shape to pivot on. I also put a little knob on mine opposite the pivot. Sliding it to cover or uncover the intake hole changes your air blast to the forge immensely. I never did like my hand cranked blowers. You get too hot entirely. When you are not heating metal switch the blower off. This saves fuel, the fire won't go out. Leave it on and your steel will blister or burn away in an instant. You may want to keep several thick pieces heating as you work on one. In my case I mounted the whole thing on some old metal stool legs bolting the leg tops to the bottom of the brake drum. Basic set up: Brake drum on top, thick rim horizontal. _____________________ |_____________________| |_____ _____| | \ _ _ / |-- fire clay/cement |______|_| |_|______| infill here. '-|__|-' bolted together | | |__| | |_ Edited by Mark S. Harris Forg-Cnstrctn-art Page 7 of 7