rdennett Posted July 13, 2009 Share Posted July 13, 2009 With charcoal, is it better to use a side blast forge or a bottom blast forge? Also, if it is better to use a side blast forge, does the tuyere need to protrude out of the wall of the forge into the coals, or can it merely be a hole in the wall? How high up from the bottom of the wall should it be? Thanks, Rob Quote Link to comment Share on other sites More sharing options...
andyrocken Posted July 13, 2009 Share Posted July 13, 2009 I am new in these forums, but it depend on what type of century forge you would like. For solids, though, the best is to have the air come from the bottom with piping. You will then need a door at the bottom of the air piping to let out ashes and a steel plate to not let large debree fall into the air pipes Quote Link to comment Share on other sites More sharing options...
Charlotte Posted July 13, 2009 Share Posted July 13, 2009 Until coal became popular as a fuel most forges were side draft. Today the japanese sword smiths use a fore that is essentially two walls with the tuyre protruding into the space bettween an angled slightly down angle. I am debating the build my self. If you plan to use a hand or electric blower rather than a bellows then perhaps it doesn't matter. Quote Link to comment Share on other sites More sharing options...
son_of_bluegrass Posted July 14, 2009 Share Posted July 14, 2009 With charcoal it is easier to design a side blast forge. I use charcoal often and it is real easy to blow the charcoal out of the fire pot with a bottom blast design. It will work with just a "hole in the wall", but that will limit somewhat the size of fire you can get hot. On the other hand, having the pipe in the middle of the fire will eventually burn the pipe up if it isn't water cooled. If you have an ash dump then theoretically it can be at the bottom, if you don't then a couple of inches for the accumulation of ash is sufficient. ron Quote Link to comment Share on other sites More sharing options...
Dave Budd Posted July 14, 2009 Share Posted July 14, 2009 I'v e used both stypes with charcoal. My normal charcoal forges are archaeologically based and as mentioned these tend to be back/side blast. I've used both with the tuyere poking out into the forge bed by a couple of inches and with a simple hole in the wall. The only real difference is that the hole in the wall is a little more durable (depending on what it's made from) but access isn't so good for heating odd shapes and getting a deep welding fire. Look up the Lively style forge for a modern bottom blast. Tim Lively makes them from washtubs with a steel pipe along the lentgh. the top of the pipe has a line of holes forming a long bottom blast fire. these can be used for general forgework but the basic design is based on the needs of a bladesmith. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 14, 2009 Share Posted July 14, 2009 Uh Charlotte; coal started to be used as a smithing Fuel in the high middle ages, (Gies & Gies, "Cathedral Forge and Waterwheel"), and the side blast went on up until sometime in the 19th century. Probably more a function of the great boom in casting stuff at the end of the American civil war. Quote Link to comment Share on other sites More sharing options...
rdennett Posted July 14, 2009 Author Share Posted July 14, 2009 Essentially my set up now is a Lively-style forge (except the bucket is round, has the top 6" cut off and has all the air holes in the center of it) acting as a fire pot hung from the bottom of an upside-down lawn mower body. My bellows are too small for it and the center of the fire is too deep to get heat in the middle of long pieces of stock. The bellows are about the size of the ones seen here. I was thinking I would construct a forge with one wall and a piece of pipe with a coupler on the end of it embedded in the wall so that I could screw a short nipple into the wall to put the air blast into the middle of the fire and replace it easily when it burnt out. The other wall would be made from dry stacked fire bricks which could be removed to accommodate irregularly shaped pieces. I use charcoal, btw, not for historical purposes, but to avoid annoying the neighbors and because it is easier to get than coal. Thanks, Rob Quote Link to comment Share on other sites More sharing options...
Charlotte Posted July 14, 2009 Share Posted July 14, 2009 Thomas,You are absolutly correct of course. We could get into a long discussion here which would ultimately depend on what the requirement for an answer was and what constitues popular in this context. Quote Link to comment Share on other sites More sharing options...
Charlotte Posted July 14, 2009 Share Posted July 14, 2009 I'm not sure too deep is your problem. With charcoal 4-6 inches deep is just enough Looks to me to be a very small bellows for any sustained large scale work. However, I've never built or worked with bellows. The Lively forge both deep and long. The total area of you air holes should aggregate to over one inch. A rough drawing would help. You know there is nothing cast in stone here so experiment until you find something that works for you with your equipment. A hole in the ground with the air blast exiting at the bottom has been used by African smiths for more years that we know. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 14, 2009 Share Posted July 14, 2009 That bellows looks weird. I have built and forged with paired single action bellows in a Y1k set up and also the double lunged great bellows in a renaissance+ set up---built the great bellows over 20 years ago now. The one in the picture looks like it has the central board but the top is rigidly mounted rather than floating. Anyway you should be able to get enough heat to forge with a bellows that size if it's properly made---how big a nozzle does it have? Quote Link to comment Share on other sites More sharing options...
rdennett Posted July 14, 2009 Author Share Posted July 14, 2009 The nozzle is 1/2". Actually, it is 1/2" schedule 40 pipe. What that means in human measurements, I have no idea. Quote Link to comment Share on other sites More sharing options...
Dave Budd Posted July 15, 2009 Share Posted July 15, 2009 Uh Charlotte; coal started to be used as a smithing Fuel in the high middle ages, (Gies & Gies, "Cathedral Forge and Waterwheel"), and the side blast went on up until sometime in the 19th century. Probably more a function of the great boom in casting stuff at the end of the American civil war. the romans were quite keen on it too around the world and all through the history (and prehistory) of pyrotechnology people use whatever they have around them as a fuel. In parts of Wales and the Midlands in the UK there were seams of coal at the surface and they were exploited before the Romans got here. Other fuels used include peat and animal dung where they are more abundant than charcoal. Various Roman writer refer to native smiths in britain using rocks and earth to fuel their forges, whether it is peat or coal I don't know. Quote Link to comment Share on other sites More sharing options...
Charlotte Posted July 15, 2009 Share Posted July 15, 2009 the romans were quite keen on it too around the world and all through the history (and prehistory) of pyrotechnology people use whatever they have around them as a fuel. In parts of Wales and the Midlands in the UK there were seams of coal at the surface and they were exploited before the Romans got here. Other fuels used include peat and animal dung where they are more abundant than charcoal. Various Roman writer refer to native smiths in britain using rocks and earth to fuel their forges, whether it is peat or coal I don't know.:cool: Yes coal has been used for a very long time. I don't think we really want to get into an acedemic discussion about the development of coal use. As you point out people use the fuel that is available. An intresting investigation is the effect of development of the coal grate on the distribution and economics of production. I think there is a limit to how much detail we can put in a response to a general question :D Quote Link to comment Share on other sites More sharing options...
Greebe Posted July 16, 2009 Share Posted July 16, 2009 With charcoal, is it better to use a side blast forge or a bottom blast forge? Thanks, Rob Back to the original question. Which is better with charcoal, side blast or bottom blast? I am considering a charcoal forge and have been wondering as well which would be best. I am interested in a larger forge that I can forge weld with. I have been using gas in the past but it is too expensive. Coal would be nice but the neighbors would probably appreciate charcoal better. Thanks Greebe Quote Link to comment Share on other sites More sharing options...
Charlotte Posted July 16, 2009 Share Posted July 16, 2009 I think my choice will be side draft since I haven't used one on a regular basis. I don't really need the coal/coke option. Quote Link to comment Share on other sites More sharing options...
Greebe Posted July 17, 2009 Share Posted July 17, 2009 (edited) double post Edited July 17, 2009 by Greebe double post Quote Link to comment Share on other sites More sharing options...
Greebe Posted July 17, 2009 Share Posted July 17, 2009 Why would side draft be better than bottom draft for charcoal? Would it just be for the volume of air delivered in one place? i.e. does a long pipe set horizontal with holes drilled in it be better as it would distribute the same volume of air over a larger surface as apposed to one large opening with the bottom blast? Thanks Greebe Quote Link to comment Share on other sites More sharing options...
Charlotte Posted July 17, 2009 Share Posted July 17, 2009 One of the identified problems with charcoal is that it needs a deeper fire than coal or coke. It is my belief that by using a side draft I can create the distance horizontally rather than vertically. I noticed the few times that I used a side draft that I had choices of heating rates both in the horizontal as well as the vertical. I also belive that charcoal will work better with a wider area but less forceful air supply. Described by one on our members as huff huff. These are speculations on my part rather than known facts. I will experiment and see how it works. If I don't like it then making or building a fire pot is always an option. I have a working gas forge so have the ability to play. Quote Link to comment Share on other sites More sharing options...
son_of_bluegrass Posted July 18, 2009 Share Posted July 18, 2009 Back to the original question. Which is better with charcoal, side blast or bottom blast? I am considering a charcoal forge and have been wondering as well which would be best. I am interested in a larger forge that I can forge weld with. I have been using gas in the past but it is too expensive. Coal would be nice but the neighbors would probably appreciate charcoal better. Thanks Greebe And here I thought I gave enough information to answer that question above. Anyway, having used both side and bottom blast with charcoal (and coal), I think charcoal works better with side blast and coal works ok with side blast and ok with bottom blast. The biggest advantage I see to bottom blast are that the tuyere doesn't burn up and an ash dump may be easier to design into a bottom blast. I find less of a problem with clinker and ash with charcoal. The biggest problem with charcoal is it is less dense than coal meaning it requires more feeding the fire with fuel. ron Quote Link to comment Share on other sites More sharing options...
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