rdennett Posted October 20, 2019 Share Posted October 20, 2019 I am finishing up a JABOD forge using anthracite in lieu of coke (can't beat the price and coke and bituminous are hard to come by), but while I can easily get steel to a good orange heat, that's as hot as it seems to get. On the plus side, I don't burn up the steel, but I do want to be able to forge weld in this thing. What variables are responsible for achieving welding heat in general? I am using 2 hair driers in a Y plumbing fitting for air blast, the cavity where the coal goes is about 6" deep (15 cm) and it's bottom is about 2" below the tuyere. The coal is piled up about 2-3" above the point where it's level with the top of the sand. Is the air too weak, the fire too shallow, the coal too coarse or what? Thanks, Rob Pic 3 hair driers pic 5 tuyere pipe with quarter for scale last pics show about as hot as it’ll get material is 5/8” mild steel Quote Link to comment Share on other sites More sharing options...
pnut Posted October 20, 2019 Share Posted October 20, 2019 How big are the pieces of coal. If they're too large there's too much open space in the firepot. You can also cool a fire with too much air. Pnut Quote Link to comment Share on other sites More sharing options...
rdennett Posted October 20, 2019 Author Share Posted October 20, 2019 This is the Tractor Supply stuff. Coal pieces are about the size of a charcoal briquette. Too coarse? Thanks, Rob Quote Link to comment Share on other sites More sharing options...
pnut Posted October 20, 2019 Share Posted October 20, 2019 Have you tried to burn up a piece of steel to see if it can? I think you have too much air. Take the hair dryer on top out and use the open hole as a way to fine tune the airflow. Acorn size pieces of coal will burn hotter than big chunks. Pnut Quote Link to comment Share on other sites More sharing options...
rdennett Posted October 20, 2019 Author Share Posted October 20, 2019 I originally used only one hair dryer. The blast seemed far too anemic, hence the second one. Quote Link to comment Share on other sites More sharing options...
pnut Posted October 20, 2019 Share Posted October 20, 2019 How big is the pipe going into the forge? Pnut Quote Link to comment Share on other sites More sharing options...
rdennett Posted October 20, 2019 Author Share Posted October 20, 2019 Indeed I did try to burn the steel. A good orange as you can see from the pics is all I could get. Quote Link to comment Share on other sites More sharing options...
pnut Posted October 20, 2019 Share Posted October 20, 2019 Try putting more fuel on the fire. It should have a few inches of fuel on top of the steel in the fire. Pnut Quote Link to comment Share on other sites More sharing options...
rdennett Posted October 20, 2019 Author Share Posted October 20, 2019 The pipe is 1-1/4 black pipe I think, a bit bigger than a quarter. I picked it up from the junkyard. Thx It’s got about two inches of coal on it, but I will add some more bricks and get it a little higher. thx Quote Link to comment Share on other sites More sharing options...
pnut Posted October 20, 2019 Share Posted October 20, 2019 Have you read the thread titled a simple sideblast forge. Just a box of dirt? It and some other jabod threads explain what you need to know to make a good sideblast forge. I use a jabod but I fuel it mainly with charcoal but I've used corn, anthracite, charcoal, bituminous and wood. They're pretty versatile when it comes to fuel. You only need to make slight changes. I liked charcoal best and anthracite wasa close second. My forge design makes coking the bituminous and corn difficult and the trench was a bit small for wood. Pnut Quote Link to comment Share on other sites More sharing options...
rdennett Posted October 20, 2019 Author Share Posted October 20, 2019 I have read that thread a few times, albeit not lately. I mostly based my design off of Torbjorn Ahmen's:. I will have another look at the JABOD thread. Thx, Rob Quote Link to comment Share on other sites More sharing options...
Chelonian Posted October 20, 2019 Share Posted October 20, 2019 Sounds like you got the "nut" size coal. I've had far more success with the "pea" size. You could try breaking up the big chunks smaller just as a test to see if that's the problem. Quote Link to comment Share on other sites More sharing options...
Donal Harris Posted October 20, 2019 Share Posted October 20, 2019 One hairdryer should be plenty. More is not always better. 2 inches of coal doesn’t sound like it is enough. Quote Link to comment Share on other sites More sharing options...
Charles R. Stevens Posted October 21, 2019 Share Posted October 21, 2019 4” below the hearth to the top of the tuyere and 4” on top of the hearth, adjust your air flow bring the hot spot just above the hearth. I melt hard fire brick, red brick and burn horse shoes in a jobod burning Rice coal for stoves. You can put nut coal on top and it will break up into smaller prices as it works it’s way down into the fire bowl. Quote Link to comment Share on other sites More sharing options...
pnut Posted October 21, 2019 Share Posted October 21, 2019 Looks like the forge in the video was effective but did you notice the rocks after he used it to forge the leaf? They were cracked pretty badly. I wouldn't recommend trying to build a forge like that unless you know the rocks are safe to heat up. A spall can be dangerous. Pnut Quote Link to comment Share on other sites More sharing options...
BillyBones Posted October 22, 2019 Share Posted October 22, 2019 I do not know who breaks that coal for TSC but i think that instead of chest nuts they go by coconuts. Break that stuff up. WEAR SAFETY GLASSES. i have whacked a piece or 2 and it shattered like glass pieces flying everywhere. I use an old metal tar bucket, place a few pieces in it and drop a 10# sledge into the bucket a few times. Like pnut said i have found that to much air seems to actually cool the fire down, especially when the fuel is a little large. I do not think it is as much air volume as it is air speed. Your air speed velocity should be about half that of an unladen Swallow. Quote Link to comment Share on other sites More sharing options...
JHCC Posted October 22, 2019 Share Posted October 22, 2019 Have you read Recommendations for Working with Anthracite? Quote Link to comment Share on other sites More sharing options...
rdennett Posted November 9, 2019 Author Share Posted November 9, 2019 Great success! I found rice coal and only used one dryer. Unfortunately, now it’s a little too hot... Got to put a choke on it. thanks for all your help! Quote Link to comment Share on other sites More sharing options...
pnut Posted November 9, 2019 Share Posted November 9, 2019 (edited) If you disconnect the dryer from the pipe you can just aim it at the pipe. Aim it more or less at the pipe for more or less air. Or a t fitting with an arm open to bleed off some air. I use an electric mattress pump and a ball valve. Have you had much popping with the rice size coal? The anthracite I used would pop more after it was broken into smaller pieces. Pnut Edited November 9, 2019 by pnut Quote Link to comment Share on other sites More sharing options...
BillyBones Posted November 10, 2019 Share Posted November 10, 2019 I cut a slot into the pipe holding my "blower" and use the top of a tin can as an air gate to adjust air flow as needed. Quote Link to comment Share on other sites More sharing options...
pnut Posted November 10, 2019 Share Posted November 10, 2019 I'll can't find the post where the person used the end of a piece of electrical conduit for a waste gate. If I can I'll post a link. Pnut Quote Link to comment Share on other sites More sharing options...
Frosty Posted November 10, 2019 Share Posted November 10, 2019 He used an electrical junction box for the control/dump gate. The blower fed a duct and the blast pipe connected at a 90*, the access plate pivots on one screw. Opening and closing the access plate acts like a dump gate. I haven't tried it myself but it's a brilliant idea. If it's not a sticky it should be. Hopefully someone knows where the post is, it had pics and everything. Is that what you're thinking of pnut? Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
pnut Posted November 10, 2019 Share Posted November 10, 2019 (edited) Yes it is. I thought it was pretty ingenious. I bet it works well. I've been looking every time I get a few minutes to spare but I haven't found it yet. I can't remember who posted it either or it'd be easier to find. I couldn't think of the term junction box for the life of me earlier. Pnut Edited November 10, 2019 by pnut Quote Link to comment Share on other sites More sharing options...
Chris Williams Posted November 10, 2019 Share Posted November 10, 2019 One of my favorite air control methods for a hair dryer, too: Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted November 10, 2019 Share Posted November 10, 2019 8 hours ago, pnut said: electrical conduit for a waste gate. I That would be Jasent. here is the thread where the junction box is used as an air dump. Scroll down for the picture. Quote Link to comment Share on other sites More sharing options...
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