Building A Coal Forge

We don’t get to see Blacksmith hacks around here too often. But even if they were rolling in on a weekly basis we think this one would be considered the special expanded edition with full-color centerfold. The sixty-five images in this coal forge build log are all commented and just begging to steal your attention for part of the afternoon.

The build mostly involves fabricating a system for injecting air into the forge and providing a mechanism for evacuating the waste ash. [BillDaCat] starts with a 3″ pipe as the ash dump, adding a latching door used to empty it when full. He then welds together a metal trough with a slotted bottom to hold the fiery fury, attaching the ash dump below. He uses a plasma cutter to add an opening in the upper portion of the ash dump for a blast gate.

If you’re excited about his build you should also check out the metal pour and the induction furnace.

[via Reddit]

21 thoughts on “Building A Coal Forge

    1. Steel is cheap. The problem is getting proper coal in places that don’t either mine it, or heat with it. Working with a real coal fire is vastly superior to the BBQ stuff.

      If someone could point me to where I could find good coal at a reasonable price in SoCal,I just might quit my day job and become a blacksmith.

    2. Car springs are pretty cheap and you can make all sorts of things with them. Bar stock can be used to do all sorts of things too. Also old files make excellent knives and can be found at garage sales and flea markets. It really doesn’t cost much to get started and do useful things. Like most hobbies it can be cheap to get into but if you really get good you will want some expensive tools later.

        1. Heat coal spring to red in a gas forge, place over mandrel, pull. You’ll find there’s a LOT of length in a coil spring!
          Or, cut off a length of coil spring (angle grinder w/ cut-off wheel), place in coal forge, heat to red & straighten with hammer and anvil.

    3. I also think forging stuff is pretty cool.. if you have the time. Asia weaponry, and some early steel and iron are all nice. Everything else you need a machine shop and modern alloys etc..

      1. You can cut one coil off and work it with most forges. But I was talking about leaf springs.

        I wasn’t talking about making a jet turbine 8). My most advanced piece has probably been a hinge. But it is a lot of fun if you have the time.

  1. Great! It has been something like six months since I started messing with metal smelting (a.k.a. forging). This article gives me what I need to build a proper forge, instead of that crappy pile of bricks and coal that I have in my backyard.

    For anyone who’s starting in this area, I would recommend starting with lead, because it (1)has a low melting temperature (~330ºC), so it can be molten on a common gas stove, and (2)it can be easily found on really old batteries that are helpless (you just need to remember to be careful with the sulphuric acid and sulphur vapours).

    Sorry for any typo, I’m almost sleeping now (-_-)

    1. PLEASE PLEASE PLEASE don’t use battery lead!!! the full reason why is a little complicated to explain, so I’ll just leave this link here:
      Be safe, use wheel-weights or flashings!

      Forging and smelting aren’t the same, however. Forging is the heating, bending, forming, and surface-welding of a material below it’s melting point, whereas smelting is the reduction of an ore to it’s metal.

      It’s all fun though :p

    2. You’re thinking about casting, smelting is NOT the same as forging. Forging = bashing hot metal into shape. Casting = pouring liquid metal into a mold.

      Lead IS easily cast, and is actually a decent material to practice hammer work because of its ductile qualities even without added heat.

    3. Uh, sorry for the mess, I was almost sleeping, as I said before. Now that I am OK, I must say: I never had any problem from SMELTING lead for casting, you just need a good exhausth. Of course that forging lead is insanity =|
      @Mr. Frykas: Okay, so suppose I buy lead from the junkyard. 90% of that lead come from old batteries (at least in the jukyards I know).
      Now talking about FORGING, I still need to build a more decent forge than the one I have. That’s all, sorry for the mess (again). =P

  2. forging lead? really?

    I’m not to eager at trying that,especially when it melt in the furnace and emit fumes…. you might want to do a little more research on the matter if you don’t wanna get lung cancer,just saying.

    Back to the project,this is real nice job there. Love the welds,looks clean and sharp. Even the trap door “holding part” is stylish. Very well done.

    Added to my project list.

  3. th3badwolf, Really? fumes are not an issue as long as you do not exceed the vaporization point of the lead, Lead melts at At 327.5 °C (621.5 °F) while it vaporizes at 1749 °C (3180 °F) you really need a HOT forge to cause vapors. Now things you splash the lead on and eat may cause you a few problems but lead has been used for century’s to make things and its quite safe as long as you don’t spill hot lead on your foot while pouring.

    1. fact is,you will overshoot the temperature and vaporize lead with that particular setup.

      The build here was used for forging a steel rod into a “very first tool” as shown in the post,therefore the steel was brought to about 800-900 C.

      You’ll basically end up with molten lead all over the place and continuous contact will lead to lead poisoning ;

      And you don’t need to reach the vaporization point to induce sublimation.

      Hope this clears my statement,just wanted to warn people that playing with lead in a forge isn’t a good and healthy idea. Try some forging clay instead,good practice for cheap.

      1. Aluminum is cheap and readily available so no need to use lead. Melts at 660C. Easily attainable with this forge using a small crucible. To melt more and to learn about sand casting Google the Gingery book #1 – Build a Charcoal Forge. First book in an awesome 7 book series. Tells you how to cast and build a whole machine shop worth of tools from scrap aluminum. Dave Gingery (and his son Vince) were hackers before hacking was cool.

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