jmhlsy Posted October 7, 2013 Share Posted October 7, 2013 OK, here is my first forge. The box is made of 3/16" plate. Inside measures 4" wide, 4-1/2" tall and 12" deep when measured through back door. Back door opening is only 2-1/4 tall, arched. Lined with 2600 degree 2-1/2" SFB, then SFB mortar, then Metricote (not in pic). Burner is standard 3/4" side arm burner, mig tip. For the flare I used a 304 SS concentric weld reducer 1" x 1-1'4. The base is made of Dana 60 and GM14 bolt parts, ie heavy. Have not fired her up yet, hopefully this weekend. What do you guys think? Be honest. I learn from my mistakes$$$. I am hoping to use this for knife making mainly. Will it work? Thanks for any input or advice. Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted October 8, 2013 Share Posted October 8, 2013 The base looks a tad small, you might have a tipping hazzard there. Other than that, fire that bad boy up. If it gets hot enough to do what you need then that in itself is the answer. My opinion, you'll be forging this weekend. Quote Link to comment Share on other sites More sharing options...
Geoff Keyes Posted October 8, 2013 Share Posted October 8, 2013 It will work, but it will have the hot spot that is common in these designs. The burners firing directly down are the problem. The other issue IMHO, is the use of hard surface materials. It will be durable and will be a good welding forge, but it's going to be fuel hungry ( you'll be burning fuel just to heat up the brick, long before you can start working), and the horizontal design is not as good for knives as a vertical (again, this is my opinion, but I've built both kinds many times). My welding forge is of this design and it takes about 30-40 minutes to come up to a good solid welding temp. My vertical forge takes about 90 seconds to come to a working heat. Geoff Quote Link to comment Share on other sites More sharing options...
windancer Posted October 8, 2013 Share Posted October 8, 2013 The two things that struck me are: 1) The vertical burner which will be super hot right below it and the heat coming from the outside of the forge will be going right up against the propane hose [all the forges I have ever used will eventually throw some heat from the outside of the forge. 2) It is gonna be real east to tip over with the small base. Propane gas is a wonderful tool [that is all I run] but also dangerous as all get out. Can't see much else from the tiny pic. The ones at the external site are also tiny. I am NOT coming down on you- I just would like it if you are still around to share more stuff with us. Dave Quote Link to comment Share on other sites More sharing options...
Dodge Posted October 8, 2013 Share Posted October 8, 2013 Finally; a good use for Chevy parts :D Sorry, I couldn't resist. I tend to disagree on the base, though. I know that is a really beefy brake drum and pretty durned heavy. However, if it does present a problem you could fabricate some out-rigging but be careful you don't create a trip hazard. Really can't say much else about it as the pic is so small. You guys have some other viewing method?? I did the "Ctrl>+" thingie but lost too much detail to make out much. I do, however, agree with the rubber hose burning hazard. I would fab a standoff bracket to keep the hose out and away from the forge. What I have done on my forges is to use copper tubing from the burner to a shutoff valve far enough away that the rubber hose connected to other side of the shut-off is not close enough to burn. Hint here is that heat rises... Anyway, have fun and be sure to update us on the shake-down cruise Quote Link to comment Share on other sites More sharing options...
jmhlsy Posted October 8, 2013 Author Share Posted October 8, 2013 Ok, hopefully that works better. The hose will never be like that when burning. I just didn't want it dangling. I was going to pass the hose through another pipe, I just didn't include it in pic. As for the base, its no lightweight. I'm guessing 60-70#. What you cant see is the whole carrier still connected. That is not just the ring gear flange. No tipping hazard there. As with this type design, apparently, there will be a "hot spot". How do you deal with it? Seems so many forges these days have a vertical injection. Do you just move the metal around a couple times? I am most interested in knife forging. Should the burner come in at an angle? I am a total newborn to this, so please forgive me for my ignorance. Thank you for your time. Jason Quote Link to comment Share on other sites More sharing options...
WayneCoeArtistBlacksmith Posted October 8, 2013 Share Posted October 8, 2013 Burners that enter at a tangent in a round or oval forge will cause the hot gases to swirl and cause more even heating. You also should have a baffle on the burner air intake to prevent the chimney effect of heat back up into the burner after the forge is shut off, also to have better control of air/fuel mixture. I always close the air baffle when I shut my forge off. Quote Link to comment Share on other sites More sharing options...
jcornell Posted October 8, 2013 Share Posted October 8, 2013 When you have the burner at Top Dead Center (TDC) you will have to use some sort of insulation to stopper up the gap between the burner holder and the burner tube. Otherwise you'll have hot gasses going up this chimney and then getting sucked into the breather of your side-arm burner. Once that happens your burner will start stuttering and otherwise misbehaving. This is simple enough if you have scraps of kaowool around. I had this problem with the current forge I'm fiddling with - a few scraps of kaowool (actually, I use Superwool) fixed this problem and let me get back to forging. The hot spot just is a fact of life - learn to use it. If you want a slow soak, put your metal to the side while working something else under the hot spot. Quote Link to comment Share on other sites More sharing options...
Dodge Posted October 8, 2013 Share Posted October 8, 2013 When you have the burner at Top Dead Center (TDC) you will have to use some sort of insulation to stopper up the gap between the burner holder and the burner tube. Otherwise you'll have hot gasses going up this chimney and then getting sucked into the breather of your side-arm burner. Once that happens your burner will start stuttering and otherwise misbehaving. This is simple enough if you have scraps of kaowool around. I had this problem with the current forge I'm fiddling with - a few scraps of kaowool (actually, I use Superwool) fixed this problem and let me get back to forging. The hot spot just is a fact of life - learn to use it. If you want a slow soak, put your metal to the side while working something else under the hot spot. Agreed. A few of the major commercial forges even have their burners coming straight in from the top.... BTW, Jason, thanks for the larger image. They eyes are the second thing to go :D Quote Link to comment Share on other sites More sharing options...
Geoff Keyes Posted October 8, 2013 Share Posted October 8, 2013 As I said above, I prefer a vertical forge for knife making. The size of the burn zone and the pass through design are why. In your design you have to heat all of the blade to work the area in the middle. Without some fancy dancing one tends to over heat and sometimes burn off the tip of a piece. The hot zone of a vertical forge is 4 or 5 inches. If you want to work in the middle of a 4 foot bar, you can. The burner comes in at an angle at the bottom of the can (and Wayne is correct when he says a round case works better). The angle promotes swirl and since the flame entry point and the stock entry point are offset, your hot spot and your stock never come together. There are two disadvantages. First, there is no floor to rest your work on. You can fix that with tongs, long stock, or a handle welded on the stock. Second, you can only fit a piece as big as the door into the forge, so it's not a good design for more general work, like scrolls. As you can see, I'm using a blown burner. I like to have the fan of the burner above the injector. I had a case where the propane leaked out and pooled in the fan. When I switched the fan on, it sparked and ignited the gas in the fan case and BOOOF, blew the fan apart. A BTM (Brown Trouser Moment). If you look at the commercial forges like yours, many of them angle the burners 20 degrees or so off vertical, to avoid some of the chimneying issues. BTW, I use a forge much like your design (single blown burner and closed at the ends) as a dedicated welding forge. The hard surface resists flux ( which Kaowool won't do) and the larger box lets me heat 18 inches at a time, which is what I want for damascus. Just my .02 Geoff Quote Link to comment Share on other sites More sharing options...
jmhlsy Posted October 9, 2013 Author Share Posted October 9, 2013 So, how do you think the forge would act if I angled the burner entry point? In my mind, if it were to enter the square forge at an angle there would still be a swirling action despite the corners. There may be a vortex in the corner, but would still be better right? Moving the burner is no big deal. Quote Link to comment Share on other sites More sharing options...
Geoff Keyes Posted October 9, 2013 Share Posted October 9, 2013 That should work, it should move the hot spot to the opposite wall, which will help out some. When you go to build a new forge (and you will, no one forge is good for everything) think about a round or oval case, They do work a lot better. Geoff Quote Link to comment Share on other sites More sharing options...
windancer Posted October 9, 2013 Share Posted October 9, 2013 If you tip the burner a few degrees so that it basically delivers the flame to hit the side first it will cause the turbulence you are after for more even heating and vastly reduce the hot spot. That tiny change will reward you a hundred times more satisfaction from your forge. There will still be a smaller hot spot where the flame reflects from the wall, but it will be off to the side when you forge in the center of the forge. When you want the higher heat just slide your material over almost against that wall. I made knives for ten years before becoming interested in blacksmithing. Warping is the worst problem for me making knives, and most of that is eliminated by even heat so the material is the same temperature clear through. A hot spot or cold spot warps like crazy and now you have another thing to deal with besides the knife. And getting the blade flat again when the bevel is forged is a maddening event. Please post some more pics when you get it up and running! Making knives is very rewarding and satisfying to me- hope you get that too :) Dave Quote Link to comment Share on other sites More sharing options...
jmhlsy Posted October 10, 2013 Author Share Posted October 10, 2013 Thanks guys for all the help. I will certainly get more pics and of it burning. Does the regulator have to be adjustable? I have a 30psi reg and good needle valve. Quote Link to comment Share on other sites More sharing options...
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