MikePierich Posted April 15, 2011 Share Posted April 15, 2011 Hi, I built a coal forge from a Honda car rim. Used 3" steel pipe and a hair dryer for air. I'm using rice-sized hard coal for fuel (my home heating fuel). I cut a 4" round piece out of 1/8" mild steel and drilled it full of small holes for a grate, and just laid it on the air inlet (hub) hole in the wheel. I put spent coal ash around the hole, built up to the level of the grate, for the fuel to set on. The grate is being burnt up. I added a 1" high ring of 6" diameter steel well casing around the small grate, put plaster's wire lath (steel mesh) over that to provide a wider air spread and keep the fire away from the small grate (and further built up the cold ash bed to the top of the ring) - but of course the steel mesh burnt up as well. Am I doing something wrong? I had assumed that the cool air supply would keep the heat going upwards and prevent the grate from burning - but no such luck. Could it be the size coal? I imagine nut coal would leave more air spaces and perhaps keep the fire from being so much in contact with the grate. I can post pics tomorrow morning if needed. Thanks in advance. Mike Quote Link to comment Share on other sites More sharing options...
Herb Upham Posted April 15, 2011 Share Posted April 15, 2011 I'd recommend buying a cast iron grate form Centaur Forge (or similar) they last well in rivet forges. If you want to stay with mild steel, use 1/4" plate (minimum) ... or better yet make a crossed collection of cast iron pieces which will emulate a grate. An alternative would be !/4" heat resistand SS ... but that would be more expensive than cast iron. Good luck! Quote Link to comment Share on other sites More sharing options...
MikePierich Posted April 15, 2011 Author Share Posted April 15, 2011 Thanks for the info, Herb! Quote Link to comment Share on other sites More sharing options...
Glenn Posted April 16, 2011 Share Posted April 16, 2011 We need to see photos of your set up. The 55 Forge is a pan type forge. The air pipe is a piece of auto exhaust with a piece of 1/4 inch rod across the 2-1/4 inch opening (see attached photo). The auto exhaust pipe burns up about an inch of the metal in a season and drilling a new hole for the rod fixes the problem. My brake drum forge has one 3/8 inch diameter bolt across a 2-1/4 inch opening and 2 each 3/8 inch diameter bolts across a 3 inch opening. (see attached photos) This leaves lots of room for air flow. Because the coal turns to coke and sticks together a bit, it does not seem to fall down into the pipe. One of the things I might suggest is to build your fire using sticks or small wood first. Put your coal fines in a bucket of water so they are covered by the water. Scoop out a hand full of the black, wet, fines and place them on (read on, over, and around) the fire. Not so thick as to smother the fire, but enough that the heat from the wood will get them to burning. Keep a hole in the center of the fire (think volcano) so the fire can escape and help burn any smoke. Add more wet fines as needed to build the size fire you want. Remember to punch the fire down as the fuel is consumed so you do not get any air pockets or caves. Quote Link to comment Share on other sites More sharing options...
MikePierich Posted April 16, 2011 Author Share Posted April 16, 2011 Thanks Glen. Like i said, I'm using rice-size coal so a rod or two won't cut it - needs to be a fine opening to retain the fuel. If I can get a larger size coal by the bag I might try that. Good to know that your pipe burns a bit too, so it must not be unusual. Maybe I can stick a sleeve into my pipe opening and let that burn up - easily replaced. I did not see a photo attached to your post. I'll try to post photos of mine tomorrow. Thanks again. Quote Link to comment Share on other sites More sharing options...
Swamptroll Posted April 16, 2011 Share Posted April 16, 2011 A good source of cast iron grates is your local plumbing supply. They have different size floor drain grates that work well in a forge and are cheap to replace if needed Quote Link to comment Share on other sites More sharing options...
Glenn Posted April 16, 2011 Share Posted April 16, 2011 Like i said, I'm using rice-size coal so a rod or two won't cut it - needs to be a fine opening to retain the fuel. Coal fines are dust. Rice is (should) be larger than dust. The idea is to wet it down, and put it on the fire wet so as it cokes up it will clump together. I have not used your coal and your coal may or may not act the same, but give it a try. Quote Link to comment Share on other sites More sharing options...
MikePierich Posted April 16, 2011 Author Share Posted April 16, 2011 That's a good idea...I should be able to get one to fit the 6" well casing perfectly. As long as it doesn't have holes bigger than 1/4" or so it should work. Thanks. Quote Link to comment Share on other sites More sharing options...
MikePierich Posted April 16, 2011 Author Share Posted April 16, 2011 I didn't say it was dust...around these parts rice coal is about 1/4" - 3/8" (see post w/pics below). I'll try the wetting thing, that didn't occur to me; but of course it won't be doing any coking or clumping until get the fire going. Thanks. Quote Link to comment Share on other sites More sharing options...
David Einhorn Posted April 16, 2011 Share Posted April 16, 2011 ....I'm using rice-sized hard coal for fuel (my home heating fuel). ... Mike, are you using Bituminous coal or Anthracite coal? If at all possible I would suggest that you could increase your happiness by switching to a larger sized Bituminous coal that is low in sulfur and low in mineral content. Quote Link to comment Share on other sites More sharing options...
MikePierich Posted April 16, 2011 Author Share Posted April 16, 2011 Here are some pix. I call it "Riceburner" because it's a Honda wheel and...it burns rice coal. Pretty simple design...Original bottom of the pot was level with the air hole. I added the 6" steel ring to provide a plenum to spread the airflow to a larger area. Figured I'd get a wider fire that way.The 1/8" mild steel grate used to be round...sort of. The edges of it burnt when I had the fire right on top of it.I raised the fire with this steel mesh (plasterer's lath) - it has the right opening to keep the rice coal from falling thru. It lasts for maybe 1-1//2 firings before it vaporizes. It's cheap so I could continue to replace it every time I fire, but a 6" cast iron grate might be good if its openings will hold the rice coal. Quote Link to comment Share on other sites More sharing options...
MikePierich Posted April 16, 2011 Author Share Posted April 16, 2011 Thanks Dave. I see you're in PA - what part? I'm in anthracite country but I think they have the bituminous out around Pittsburgh. I'll look around for some chunk bituminous here. Obviously I'm using the hard rice because I have a whole bin full of it for the house, but if the other stuff is available nearby I'll definitely try it. Quote Link to comment Share on other sites More sharing options...
MikePierich Posted April 16, 2011 Author Share Posted April 16, 2011 Oh OK, now I can see your pix. Good idea with the firebuilding to get clumps - I'll try that too. Would solve the grate problem - sounds like an art that will take a few attempts to learn. Thanks. What do you guys think about the raised fire to spread the airflow to get a wider fire? Quote Link to comment Share on other sites More sharing options...
Drewed Posted April 16, 2011 Share Posted April 16, 2011 1/8" mild is way to thin. That will burn up. Centaur forge has them for about $25: http://www.centaurforge.com/Cast-Iron-Tuyere/productinfo/TUYERE/ You can also find them on e-bay Or try the floor drain thing. Quote Link to comment Share on other sites More sharing options...
David Einhorn Posted April 16, 2011 Share Posted April 16, 2011 Thanks Dave. I see you're in PA - what part? I'm in anthracite country but I think they have the bituminous out around Pittsburgh. I'll look around for some chunk bituminous here. Obviously I'm using the hard rice because I have a whole bin full of it for the house, but if the other stuff is available nearby I'll definitely try it. I'm near Gettysburg. The closer you get to Bituminous "shop coal" the easier it is to forge. Also, the use of a deep fire-pot allows the fire to have the three zones of a blacksmith's coal fire, the carbon rich area, the neutral area, and the oxygen-rich area. A deep firepot moves the neutral area to approximately level with the fireplace. If memory serves me, then there are plans on this forum/site for welding one or more nice firepot/tuyer combinations. I would suggest finding someone with a really nice firepot and forge, and spending some time working at it and learning about maintaining a coal fire in a really nice forge. If you come down to the yearly "Blacksmith Days" at the Carroll County Farm Museum, in Westminster, MD, May 14 and 15, http://www.bgcmonline.org/docs/bsd11.html that would be a good opportunity to help you with any information that you might need. It is a really good event, especially for the price. Frank Turley and Robert Elliott will be demonstrating. There are people tail-gating so it is possible you could find a firepot at a price you can afford. I picked up a Champion fire-pot with tuyer for $25 there a few years ago. I really like Champion fire-pots, as they are a good size, with well-designed tuyers. It is pretty certain that in order to be covered by liability stuff that the guild will ask you to join the guild in order to be able to enter the blacksmithing school, $25 yearly membership and a release form. After joining you could then enter the school and use the equipment during any event or monthly meeting and get one-on-one learning assistance by simply asking. Quote Link to comment Share on other sites More sharing options...
MikePierich Posted April 16, 2011 Author Share Posted April 16, 2011 Thanks Drewed. Quote Link to comment Share on other sites More sharing options...
MikePierich Posted April 16, 2011 Author Share Posted April 16, 2011 Way cool, thanks. I'll put that on my calendar. I'm thinking the anthracite might not get as hot since the bituminous coal probably burns faster - like the difference between burning pine and oak. Less btu's but faster heat. I also think my fire is mostly oxygen-rich. I left a couple of files in there for a while and they burnt up like firewood...which would require oxygen as in a cutting torch. I think for the time being I'll pile up my coal to get it as high as I can, that way there'll be more of a sweet zone in the middle to bury the workpiece in. I might also increase the depth of the pot by adding steel around the rim. Thanks to all you guys for all your help. Quote Link to comment Share on other sites More sharing options...
David Einhorn Posted April 16, 2011 Share Posted April 16, 2011 ....I'm thinking the anthracite might not get as hot since the bituminous coal probably burns faster.... http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html The Auto-Ignition Temperature Anthracite - glow point........ 600 1112 Bituminous coal - glow point 454 850 ------------------------------------------------ http://www.engineeringtoolbox.com/coal-heating-values-d_1675.html Coal Grade..........................Heating Value .........................................(Btu/lb) (kJ/kg) Anthracite............................12910 30080 Semi-Anthracite....................13770 32084 Low-volatile bituminous..........14340 33412 Medium-volatile bituminous.....13840 32247 High-volatile bituminous A......13090 30499 High-volatile bituminous B......12130 28262 High-volatile bituminous C......10750 25047 Subbituminous B...................9150 21319 Subbituminous C...................8940 20830 Lignite..................................6900 16077 Quote Link to comment Share on other sites More sharing options...
MikePierich Posted April 16, 2011 Author Share Posted April 16, 2011 Interesting, thanks. I should show that to my coal guy. He'd probably roll his eyes and spit a wad of snuff... Quote Link to comment Share on other sites More sharing options...
Glenn Posted April 16, 2011 Share Posted April 16, 2011 The 1/8" mild steel grate used to be round...sort of. The edges of it burnt when I had the fire right on top of it. I suspect that the holes are too small and do not allow enough air to pass through, If the air escaped out the side this would account for the burning of the metal in this area. The one issue that sticks out in your photos is the inlet position of the air pipe. It should be close to the top, not the bottom, of the air pipe. Ash will fall into the air pipe and with the T at the bottom it will fill up quickly. With the T at the top you have a container for the ash that will have to fill up to the bottom of the T before it restricts the air flow. Study the fire diagram (attached). It shows several things that folks sometimes miss. 1st is the shape of the fire ball. 2nd is sweet spot of the fire and the placement of the mental in the fire. 3rd is the depth of the fire. All this changes and adjusts with the size of the metal being heated, the shape of the heat needed, and the fire pot design. Quote Link to comment Share on other sites More sharing options...
MikePierich Posted April 17, 2011 Author Share Posted April 17, 2011 Thanks, good diagram. Confirms that I need to heap the fire up higher because I was having to place the work on the diagonal like it shows there. Good point about the edges of the grate. I have no issue with ash buildup in the pipe, for some reason. At the end of a several-hour session there's almost none in there, let alone enough to build up and clog the inlet. I assume the small holes keep all the coarse stuff from falling thru, and the blower sends the fine ash up thru the fire. Quote Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted April 19, 2011 Share Posted April 19, 2011 Check out this thread: Cast iron floor drain for coal forge? for some more good information. Quote Link to comment Share on other sites More sharing options...
MikePierich Posted April 19, 2011 Author Share Posted April 19, 2011 Thanks Grant, good info. Also, looking at that monster blower he has on that thing, then at my little El Cheap-o hair dryer, I can see why my fire doesn't exactly...well, "set the world on fire", as they say. Check out this thread: Cast iron floor drain for coal forge? for some more good information. Quote Link to comment Share on other sites More sharing options...
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