Latest Update:
Thursday May 01, 2008.
Showcasing now 14 different blacksmith's coal forges on 12 pages. The Coal Forge series offers a look at how other smiths from around the world, build their forges. The coal forges are conveniently linked on three jump pages; The Coal Forge, The Coal Forge 2, and The Coal Forge 3.
The Forge Design series (about to be updated again) describes the theory and practice of building a coal forge from scratch for specific work it is to perform.
The Fire pages offer the neophyte smith a reference for using the fire and how the fire works.
The Blacksmith's Forge
The forge is the center of focus of the blacksmith's work and his shop. It is in the fire of the forge that the iron is heated to incandescent red, orange, yellow and white heats. For only at these highly elevated temperatures can the iron and steel be made plastic enough to be shaped and deformed easily and without damage to their granular structure. This series of articles focuses on the traditional blacksmiths coal forge.
These pages have several purposes:
- To show and describe the forges used by a number of different ornamental iron and blacksmiths' shops in different parts of the USA and other countries.
- To assist the first-time forge builder to design and build a forge with which he or she will be able to do the work they want their forge to do.
- To give the newbie blacksmith a thorough understanding of the blacksmith's fire so he or she will be able to use it more effectively and more easily understand the design process of forge building.
What is a forge?
The forge is the hearth upon or inside of which the fire is kept for the purpose of heating the iron. The forge provides a safe fire resistant structure in which to keep the fire, and to which a source of air blast can be piped to increase the heat of the fire. Most modern shop forges incorporate a chimney structure to remove smoke from the fire, out of the shop safely. The blast of air raises the heat of the fire in the same way as blowing softly on a small flame to help light a campfire. Click here to see some pictures of forges or follow the links above to one of the Coal Forge pages.
The blacksmith's forge has remained similar in design and purpose for millenniums. Some of the differences being in the materials we now use to build our forges and the source of air supply and delivery. Despite its modern look, the modern forge works exactly the same as those of its predecessors.
What fuels are used for the fire?
Charcoal was the original forge fuel. A beginner will immediately ask the question here "can I use bar-b-que charcoal?" The answer is no, not bar-b-que charcoal. Charcoal is made from plant material (usually wood and/or straw and clay or some other filler material) that has been heated to drive off volatile matter with almost pure carbon left behind. By a process of distillation in which wood is heated hot enough to burn, but starved of oxygen, most of the compounds in the wood are driven off in the form of vapors or smoke leaving carbon behind. Before the industrial era this was accomplished by stacking logs in a pile and burying with dirt. A small fire was built at the bottom of one end and a hole opened in the top of the mound to vent the vapors or smoke. The air supply was restricted to allow the fire to burn hot enough to literally char the wood into 'coal', but at the same time starving the wood pile inside the mound from getting enough oxygen to burn completely. The idea was to put out the fire after the wood was converted to charcoal. After the burn most of the wood was recovered in the form of charcoal with only minor losses due to some wood being closest to the fire. Visitors to this website will need to search elsewhere for instructions on making charcoal.
Between approximately the 15th and 18th centuries, blacksmiths gradually began the change to coal as their primary source of forge fuel. Not all coals are suitable for forge fuels, and the lack of access to a source of good coal and the lack of success with coal slowed its adoption as the primary fuel for blacksmiths. Even today blacksmiths must be very picky about how and where they obtain their coal, and most smiths locate good sources by word of mouth. In some regions of the world, coke is easier to obtain. The blacksmith should not pay more for coke than coal because he can make coke himself as a natural progression in using the fire throughout the day.
The Fire.
Here are several pages to help the new smith learn to use the fire. Beginning with The Fire, an amateur smith or beginning smith can learn how the fire is used and troubleshoot problems he may be having with his fire. With all the misinformation spreading through the small blacksmith chapter groups it appears that a good source of info from someone who has actually used a blacksmith's fire to produce ironwork, is in order.
The another link here Lighting the Fire is written for beginners. This page written exclusively for beginners, details several different methods of lighting the blacksmith's coal fire. Look for a few photos to be placed on that page soon.
The next page is Using the Fire which describes the theory of the blacksmith's coal fire and details how to maintain and use the fire to heat iron for forging and welding. Photos will be added to this page a few at a time as I have time to shoot them. Heats and colors are described on this page along with fire tool use so the beginner can better understand what he or she needs to get off to a good start.
Forge Design.
The Forge Design pages (now numbering 15 separate pages and more material is being added) offer lots of ideas to help in the design and construction of good custom built forges. Lots of pictures of real-life pictures of the forges built by professional and historical blacksmiths from around the world. The style and method of constructing the shop forge is a matter great consideration and individual preference to the blacksmith who will be using it everyday. A blacksmith cannot use 'just any ol forge'. Placement of the fire, chimney, size of hearth, height, and materials and construction considerations are discussed. This series has become a great companion resource to The Coal Forge pages.
Here I need to make the point that time and again, amateur smiths too often build their forges with little or no knowledge of what they are doing. Worse yet, they usually build another forge to replace the first failed attempt, and again they fail to learn from previous mistakes.
These pages were created to share all of my sources of forge design. The smith that fails to understand these fundamentals will ultimately fail to build a good forge the first time and probably ever time if they also fail to learn from their mistakes. Let me give these readers a hint. See how the professionals build their forges. Learn from the mistakes of others and see what they did to design the most practical forges for their shops. Forges must be designed with careful consideration to the work they will encounter throughout the life of the forge. This design aspect which is so often unknown or overlooked by beginners and first time forge builders, has a strong impact on the productivity and effort to produce ironwork. The Forge Design pages - and the Coal Forge pages- were published specifically to help new smiths start out with the best forges possible.
Gas Forges.
What about natural gas and Propane?
Blacksmiths today now have access to gas-fired forges and furnaces as well as coal and coke forges to heat the iron. Gas forges offer the convenience of not having to worry about where to buy good smithing coal. Gas forges are not as hot as coal forges and take longer to heat the iron to a forging temperature. In all cases the lower heat value of gas means longer heat times and more oxidation. However the size and capacity of the gas forge allows a much larger number of straight un-worked, or nearly straight bars to be placed in the fire at one time, and therefore can heat more un-worked bars over a longer period of time than the coal forge. This last point is the reason why a business needing forgings is more likely to have a gas forge than a coal forge. On the other hand the coal forge is still king when higher heats on larger and heavier bars are needed, and fewer bars are to be heated for work, and for heating work of more complex shape which cannot be placed inside the limited interior area of the gas forge. Each type of forge (coal or gas) has its advantages and disadvantages, and this is why each shop must choose what type of setup works best in their situation. Many shops employ both gas and coal forges and use them each for specific tasks such as-coal for heavy bars and gas for large numbers of small work.
Most gas forges never get very hot.
One large drawback of gas forges is that most factory-made gas forges cannot reach welding heat. Don't be fooled by the claims of amateurs that they forge weld all the time with this or that forge. Most amateurs are simply boasting of being able to do something that they have never actually done. Most factory-made gas forges cannot reach welding heat, and the few that can, will heat the iron much more slowly. However the lower temperature and slower heating is actually helpful to most beginner smiths and those with poor fire skills because, a cheap gas forge will not heat the iron to a sizzling white heat- suddenly destroying the iron. Instead the iron will waste away (slowly burning) in the fire over a long period of time, but the inexperienced smith need not worry about suddenly destroying his iron by accidentally leaving it in the fire too long. On the other hand...
Some gas forges CAN get hot enough to fire weld!
There are some homemade and custom designed gas forges that can reach this higher heat. If the reader is going the gas forge route, I recommend visiting Ron Reil's website to see how to design the hotter custom-made forges at http://ronreil.abana.org/design1.shtml . Ron has compiled a large collection of designs both of his own and those sent to him by friends. Lots of designs of burners, insulation, most are inexpensive. These guys keep adding more stuff.
Special fluxes needed for fire welding with gas forges.
Since gas forges will take longer to heat iron, more oxidation will develop during the extended heating period. Special fluxes are used to deal with the additional scaling which results from this oxidation. Centaur Forge sells these fluxes.
Latest Update 01 May 2008.
The author can be emailed at address in picture below:
December 1999