Irondragon Forge ClayWorks Posted March 29, 2017 Share Posted March 29, 2017 Just getting started on our propane forge, made from an old outdated 20 pound tank. Cut out the ends and opening for the burner holder so far. In the picture is the angle I think will work for the burner, a straight edge is in it to show the angle. Have not welded the holder in yet, waiting to see if all agree with the angle. Also shown is the GACO-750 burner that has a 1 ¾ inch opening and a .0625 orifice. When taking out the tank shutoff valve I had to make a tool out of 2 inch square stock using the metal cutting band saw. The real challenge was holding the tank to keep it from turning, finally had to strap it to a tree with ratchet strap’s and use a 5 foot pry bar (really tested the tensile strength of the straps). Cutting the tank with the plasma cutter was no problem. Filled it with water then added 1 cup of chlorine bleach, let it sit over night. Dumped out the water and no smell so the oil was washed out. Not even a “woof” when cutting. The next step will be welding on legs then lining with 2 - 1 inch layers of Kaowool & ridgidize them. We plan on using kiln shelf for the floor and Satanite. Comments and suggestions are very welcome. Quote Link to comment Share on other sites More sharing options...
WayneCoeArtistBlacksmith Posted March 29, 2017 Share Posted March 29, 2017 Have you read the attachment Build a Gas Forge on the Forge Supplies page of www.WayneCoeArtistBlacksmith.com? I would lower the angle of the burner to where it enters at a tangent so that the flame swirls around inside the forge, that is unless you want a hot spot. It would have been better to use the top collar off the tank for a templet for the size of the openings, then the ends of the tank could protect the ceramic blanket and the casting. If you had used the collar you would also have wound up with a D shaped opening and a flat floor. I don't know anything about that burner but it seems overly large for a 20# Propane bottle forge and an overly large orifice Let me know if I can help you. Wayne Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted March 30, 2017 Author Share Posted March 30, 2017 Yes I did read the attachment, was planning to put shelves at each end for the D opening. I don't think the picture angle shows the opening correctly, there is a 2 1/2 lip all around. We did use the collar as a template but cut the hole as a circle. The orifice is replaceable so I was going to wait on getting a .035-.040 to see if I can tune it with the .0625 that's in it. The main thing I am concerned with is the angle of the burner tube, which I have changed. The picture shows the new angle. Quote Link to comment Share on other sites More sharing options...
WayneCoeArtistBlacksmith Posted March 30, 2017 Share Posted March 30, 2017 You will get a hot spot where the flame hits the other side. I would place it more nearly level so that the flame runs along the top of the casting and swirls around the inside causing a more nearly even flame. If you have already welded the burner bracket you would have to cut it loose to change the angle of the flame. Let me know if I can help you. Wayne Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted March 30, 2017 Author Share Posted March 30, 2017 Thanks Wayne Dropped the burner tube to nearly horizontal. Think that will work? I haven't attached the legs, so I can rotate the body if necessary. Also, with the six set screws I have some adjustment of the burner angle. Quote Link to comment Share on other sites More sharing options...
WoodnMetalGuy Posted March 30, 2017 Share Posted March 30, 2017 I think Wayne was suggesting not that you rotate the forge body, but that you change the way the tube enters so that it's more tangental to the center space, rather than pointing across the middle of it. However, in reading some material Ron Reil has on his website, he doesn't seem to totally agree with that philosophy, and even likes having a hot spot in there, so he can concentrate heat on his stock where he wants it... -- Dave Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted March 30, 2017 Author Share Posted March 30, 2017 I did change the burner tube entry angle and with the burner I'm planning to use the flame is much larger in diameter than the home made burners. All the forges I have seen in use, the flame does contact the work but with the flame swirling I thought scale may be limited. Quote Link to comment Share on other sites More sharing options...
WoodnMetalGuy Posted March 30, 2017 Share Posted March 30, 2017 7 minutes ago, Irondragon Forge & Clay said: I did change the burner tube entry angle OK, could not tell from the photo. It looked to me like it was still pointing directly into the middle vs. coming in at a tangent. Either way I'm not sure how much that matters. I think the key to heating is how much time the flame spends in the forge and how complete the burn is. Earlier today I ran across some interesting information in this document: http://azblacksmiths.org/wp-content/uploads/2016/04/Forge-build.pdf. Here's a quote from that: Quote The blacksmithing lab provided another bit of information that seems counterintuitive. The lab has 12 forges whose housings are made from pipe. Some are 12”, some are 10” and others are 8” diameter. They all use 1” thick ceramic fiber blanket and all have the same the heat source: 2 burners, made from ¾” pipe with .o23 MIG tips for jets. And they are all plumbed into the same 500 gallon propane tank and each has a regulator set to around 12 psi. It would seem that the 8” forges would get hotter than the 12” forges. After all, there is less volume to heat and keep hot. We all know that the bigger the house, the larger sized heat pump is needed to heat or cool. In the lab however, observation tells us that the 12” forges get hotter than the 8” forges. Why? The answer was provided by one of my students who is an HVAC engineer. The flame needs room to complete its burn before it is interrupted (in this case, by the opposite side of the forge). Disrupting the burn means that some of the fuel is not burned, which not only means it doesn’t produce heat, but it actually cools off the flame in the same way that richening the mixture in a car engine makes it run cooler. -- Dave Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted March 30, 2017 Author Share Posted March 30, 2017 Thanks Dave, interesting read. With the Gaco-MR750 kiln burner I can idle it down to 2psi and get a soft flame at 76,880 btu or crank it up for 243,140 btu at 20psi. It may prove out to be too much burner though. Quote Link to comment Share on other sites More sharing options...
WayneCoeArtistBlacksmith Posted March 31, 2017 Share Posted March 31, 2017 4 hours ago, WoodnMetalGuy said: The flame needs room to complete its burn before it is interrupted (in this case, by the opposite side of the forge). Disrupting the burn means that some of the fuel is not burned, which not only means it doesn’t produce heat, but it actually cools off the flame in the same way that richening the mixture in a car engine makes it run cooler Thus the reason for the flame to swirl around in the forge. Scale is formed when oxygen contacts red hot metal. If the forge is running rich so that all of the fuel is not burned due to lack of oxygen scale is not formed, until the metal is taken from the forge. That is the reason that I can weld Damascus billets without flux. Let me know if I can help you. Wayne Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted April 1, 2017 Share Posted April 1, 2017 The right position of a burner in a forge, has to due with several factors; one of them is just how hard (forceful) the burner's flame is. You have stated that your chosen burner has a soft flame, and everything I've seen of the old wasp-waist burners show them to have very soft flames. All things considered, I would say the original position in your first photo will work just fine. In fact, you may need to start with the burner turned up full blast, and only turn it down after the forge interior is completely heated, to get the burner to run smoothly. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted April 5, 2017 Author Share Posted April 5, 2017 Decided to return the burner tube back to it's original angle. Welded it in yesterday. Now to insulate it with Kaowool. Spent today cannibalizing a BBQ that someone dumped on our road for the cart. It's coming along. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted April 7, 2017 Share Posted April 7, 2017 Good score; that should work fine. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted April 9, 2017 Share Posted April 9, 2017 "The blacksmithing lab provided another bit of information that seems counterintuitive. The lab has 12 forges whose housings are made from pipe. Some are 12”, some are 10” and others are 8” diameter. They all use 1” thick ceramic fiber blanket and all have the same the heat source: 2 burners, made from ¾” pipe with .o23 MIG tips for jets. And they are all plumbed into the same 500 gallon propane tank and each has a regulator set to around 12 psi. It would seem that the 8” forges would get hotter than the 12” forges. After all, there is less volume to heat and keep hot. We all know that the bigger the house, the larger sized heat pump is needed to heat or cool. In the lab however, observation tells us that the 12” forges get hotter than the 8” forges. Why? The answer was provided by one of my students who is an HVAC engineer. The flame needs room to complete its burn before it is interrupted (in this case, by the opposite side of the forge). Disrupting the burn means that some of the fuel is not burned, which not only means it doesn’t produce heat, but it actually cools off the flame in the same way that richening the mixture in a car engine makes it run cooler. " Two 3/4" burners in a forge made from 8" diameter pipe must result in massive back pressure; which must result in choked air intake; which must lead to a gas rich flame, which is bound to be heavily reducing, and therefore cold and carbon monoxide rich. there is no mystery here. If they try to counter by reducing gas intake the back pressure will only tend to do a better job of reducing air intake, until both flames have been reduced so much that not enough heat is coming into the forge to properly heat it, anyway; a no win situation. One burner needs to go away, and the other burner needs to be swhiched out for a 1/2" burner before that forge will ever run right. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted April 15, 2017 Share Posted April 15, 2017 "Thanks Dave, interesting read. With the Gaco-MR750 kiln burner I can idle it down to 2psi and get a soft flame at 76,880 btu or crank it up for 243,140 btu at 20psi. It may prove out to be too much burner though." If so, that nice large burner port you installed can hold a smaller burner in it, just as easily. But, I think the present burner will work out the way you want. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted May 27, 2017 Author Share Posted May 27, 2017 The build is still in progress however other obligations/projects keep getting in the way. We managed to get the last layer of ridgidized kaowool installed today for 2 inches total. Next is to coat it with two layers of Satanite for a half inch coating then decide which high alumina kiln shelf that will be sacrificed for the floor. Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 28, 2017 Share Posted May 28, 2017 Looking good. I especially like the color of the blanket. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted May 28, 2017 Share Posted May 28, 2017 The way I like to mount a kiln shelf, for use as a floor, is to cut notches into the cylinder openings at each side of both ends, and just slide the shelf into them; don't forget to place a pillow of ceramic wool under the shelf for extra insulation. Don't bother rigidizing the wool that you use for a pillow, because you want it to remain springy untill it takes a set; this provides added support to the shelf, in the middle area of the forge. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted May 28, 2017 Author Share Posted May 28, 2017 Debbie was planning to set the kiln shelf in the Satanite. I like the idea of notching the body and making the floor longer. Thoughts on both. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted May 28, 2017 Share Posted May 28, 2017 I've never had a moments trouble from a sagging, or shifting kiln shelf placed in notched recesses. BUT, I've never used Satanite, so I don't know how well it would work. I always supposed it was only used for a high heat hot-face coating. Lately I'm reading about guys using it like regular refractory. That could work quite well. If'n I wuz in your britches, I'd go with HER druthers; with the only question being is she going to get herself in trouble doing things her way; that would be worser for ya, than if'n you go again her wishes. So, it boils down ta, is; she going to make a mess? if no, than go her way and save the pain Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted May 28, 2017 Share Posted May 28, 2017 I'm supposing that she is proposing the use of a thick enough layer to constitute a lip that supports the shelf, rather than a solid slab, which would be nearly as bad as hard brick about creating a heat sink. A lip would would provide a small void beneath the kiln shelf. At either end of the cylinder, you could drill two or three small holes to allow some airflow into that area, reducing the amount of heat transferred to the insulation an important little bit, while only losing efficiency by that same little bit; a good trade off, in that area. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted May 29, 2017 Author Share Posted May 29, 2017 Seems we had a slight misunderstanding on my part (not unusual) about how she plans to do the inside. The plan is to coat the whole interior with satanite and harden it up, then cut the kiln shelf to just cover a small portion of the floor, with kayowool filling the void underneath. She wants to be able to remove the shelf easily. I'll go with that, it's her forge after all. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted May 30, 2017 Share Posted May 30, 2017 3 hours ago, Scrambler82 said: If you have a dense fire brick floor, can you just lay the alumina tile on the brick ? Also, does it need something to hold it in place, like an adhesive ? You can just lay the tile on top, it will still help that way. But, you are way better off trapping it within the shell, and changing out the brick for ceramic board, or blanket. I like to trap cast refractory, various bricks, and kiln shelves; this way, they can expand and contract at their own rates. Otherwise you pretty well need to make a good match up with various materials coefficient of expansion, which greatly adds to your level of frustration. 13 hours ago, Irondragon Forge & Clay said: Seems we had a slight misunderstanding on my part (not unusual) about how she plans to do the inside. The plan is to coat the whole interior with satanite and harden it up, then cut the kiln shelf to just cover a small portion of the floor, with kayowool filling the void underneath. She wants to be able to remove the shelf easily. I'll go with that, it's her forge after all. That is a darn good way to boot. How does she want to deal with the forge openings? I assume she wants to construct them only after the coating and kiln shelf are installed. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted June 4, 2017 Author Share Posted June 4, 2017 The forge openings will be fabricated after the interior is done and the burner is operating satisfactorily. That will be my job and pieces of kiln shelf or soft fire brick will probably be used to partially seal off the openings. I have a couple of designs in mind but she will have the final say. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted June 5, 2017 Share Posted June 5, 2017 I never used a door on a forge, in the past. But after seeing a few made by guys on this group, I would recommend them on most forges, now. Just about any enclosure you can dream up for the exhaust opening, to pass work through (including baffle walls), can also be worked into a door arrangement; this allows better access to the forge for oversize pieces, and for making repairs. That constitutes valuable added abilities for limited additional work; a bargain any time you can get it. Quote Link to comment Share on other sites More sharing options...
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