MaxwellB Posted April 24, 2019 Share Posted April 24, 2019 I purchased this forge: At the beginning of 2019, figuring I needed a hobby. Making knives and small things like that seemed like a good idea. Who doesn't love fire and hitting things with a hammer? I received the forge fairly quickly from the middle of Eastern Europe, and I went about getting it action-ready according to various posts I've seen here, and information I've sniffed out from other interweb sites. After putting a bunch of stuff inside of it to see if I could increase the efficiency, I came to the conclusion that there just wasn't enough of the right stuff in there. So I set about tearing out the old, and putting in the new. I started with ripping out the old kaowool and coatings I had on there, and putting in 2" of wool instead of the stock 1" that the forge came with. Exhibit A, post rigidizing and test burning: Next, I purchased some Kast-o-Lite 30 and lined the sides with about 1/4" on the sides and 3/8" on the floor. Enough to provide ample protection for the wool on the floor of the forge, as well as increase the efficiency of the forge. This also reduced the interior dimensions significantly. Exhibit B, forgive the perspective: The "stock" interior dimensions were, according to the original sale listing, 5.6" x 5.6" x 16". The new (approximate) dimensions after the layering of the wool and the KOL is about 4" x 4" x 16". This means the "stock" interior volume would be about 501.76 cubic inches. The new volume is approximately 256 cubic inches. So a hair over half the original space was taken up. In theory this will make the two burners (small in comparison to homemade burners) the unit came with more efficiently heat up the interior, and allow higher temperatures to be reached with less PSI resulting in greater fuel efficiency. In theory. I hope. The forge and it's new guts are now in it's bag o' humidity, where it'll remain for the next few days (until Saturday at the earliest). Exhibit C: The new dimensions will undoubtedly make it more difficult to work certain stock sizes in it, but I really don't foresee myself working with anything that's going to be wider than 4" and longer than 16". The only thing I can see happening is that trying to straighten coil springs (like the one see in exhibit c) will mean I have to cut off a length first instead of unraveling into a long piece of stock. But that's why man invented angle grinders. I will update this post again when the "cure" is done and take a picture or two of the test fire, as well as any issues I came across. I used about 5lbs of Kast-o-lite to do this. I probably could have used 6, just to make sure I wasn't spreading anything too thin. But that's why I left the roof of the cavity until last, as I had the burner holes to dance around and could spread out the product a little thinner. Quote Link to comment Share on other sites More sharing options...
Latticino Posted April 25, 2019 Share Posted April 25, 2019 Just be careful. You can have too small a chamber for effective combustion as well as too large a chamber to heat effectively. A lot depends on turndown capability of your burner. And then there is the issue of flame length. This forge doesn't have the short "soft" flame of a multiport burner. Good luck. Quote Link to comment Share on other sites More sharing options...
Frosty Posted April 27, 2019 Share Posted April 27, 2019 I have to ditto Latticino on this one Max. Back pressure can pretty much end NA burner effectiveness. You're pushing the lower limit of 1/2 the appropriate volume. Two 3/4" burners is appropriate for say 500-700 cu/in but 256? Except for the shape that's small for a single 3/4" burner. Or are those smaller dia. burners? Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
MaxwellB Posted April 27, 2019 Author Share Posted April 27, 2019 Just checked the burners, they're 1". Weather permitting I'll be putting the burners in the forge tomorrow afternoon when I get off work and test firing everything, seeing how that goes. Worse case scenario is I rip out the KOL and the second layer of wool, and just put up a thicker KOL coating over the first layer. But I'll definitely have more info (hopefully) tomorrow after the burn. Quote Link to comment Share on other sites More sharing options...
Frosty Posted April 27, 2019 Share Posted April 27, 2019 Those mixing tubes are 1"? Are you sure, you aren't measuring the flare or something else? As mentioned in discussions about these forges before, I'd expect welding heat running two 1/2" T burners, that's 1/4 the nominal output of 1" burners. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
MaxwellB Posted April 27, 2019 Author Share Posted April 27, 2019 The flares are 1". I thought that's the measurement you were referring to. After checking again, the flares are 1" with 1/8" wall. So assuming the mixing tube is 1/8" wall as well, I would assume they're 3/4". They fit into the flare with just a sliver of daylight between the exterior of the mixing tube and the interior of the flare "coupler". Quote Link to comment Share on other sites More sharing options...
MaxwellB Posted April 27, 2019 Author Share Posted April 27, 2019 So, even though Mother Nature seems to have a chip on her shoulder for good ol' Chicago, I was able to fire the forge today and see if I messed anything up. So, for your review. Burners right after being lit: Burning on low pressure: Higher pressure burn, about 7 or 8 PSI: Back burner seems to be running more efficiently than front. Perhaps the door? Perhaps better placement (lower/higher, angle, etc). Not sure: And after forge is off and cooled down. No apparent cracks or deformation in the KOL layer: So, wiser smiths of the world, what would you say about this... Would you say that the interior is too small, causing the heat to not be able to distribute properly, causing the cold spot in the middle of the forge? What could be causing the rear burner to be hotter than the front? Could it be the door is there, trapping more heat? Could it again be the heat isn't circulating as efficiently so it's just essentially a blast zone? Tips to correct any deficiencies noticed would be appreciated as well. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted April 27, 2019 Share Posted April 27, 2019 No; I would say that you have no problem at all. Quote Link to comment Share on other sites More sharing options...
MaxwellB Posted April 27, 2019 Author Share Posted April 27, 2019 Is that cold spot between the burners normal then? Quote Link to comment Share on other sites More sharing options...
Eventlessbox Posted April 27, 2019 Share Posted April 27, 2019 Are your chokes open dead even? Have you tried with the door open? Not speaking from experience. Simply brainstorming. Quote Link to comment Share on other sites More sharing options...
Latticino Posted April 28, 2019 Share Posted April 28, 2019 Looks like a win to me also, assuming it gets hotter after being run for a while and all residual water driven off your refractory. Happy forging. Quote Link to comment Share on other sites More sharing options...
MaxwellB Posted April 28, 2019 Author Share Posted April 28, 2019 Latt - Oh yeah... There was plenty of steam. EVERYWHERE. It was coming out of both ends and looked like a Cheech & Chong video. I was worried at first because it kept coming. But then I thought of all the water in the refractory and the water on the wool I buttered with, and the humid conditions of the day. Event - I had the front choke open a bit more than the back, simply because I wanted to try and bring in more air to negate the hot exhaust getting drawn in. I don't have a welder, so I can't tack a heat shield around the choke like I would like to, or even tack a plate over the top of the front to keep exhaust/dragon's breath diverted. I've gotta see how low the burners are sitting inside and see if I need to bring them down further. Everything I've read say they should be flush with the refractory or recessed slightly, up to 1/8". That might be the ticket. I'd still like to see about that cold spot in the middle. The obvious first troubleshooting step is to turn the burner assembly around and see if the front gets hotter than the back. Then there's an issue with the burner assembly not diverting evenly. If the back still stays hotter, then it's an issue with the design or the reline and I go from there. Quote Link to comment Share on other sites More sharing options...
Eventlessbox Posted April 28, 2019 Share Posted April 28, 2019 For sure. Keep us posted. I've yet to find a free moment to put the Kast-o-lite in mine. Too busy finally getting A/C in the tiny house. Did you Kast-o-lite the door at all or just use the stuff they sent it with? Quote Link to comment Share on other sites More sharing options...
MaxwellB Posted April 28, 2019 Author Share Posted April 28, 2019 I had put the stuff they sent with first, then when I Greenpatch'd the forge I put it on there. Right now it's just rigidized wool, and I might keep it that way. Or if I find where I put that Greenpatch bucket, I'll put a bit on there just to protect the wool. Quote Link to comment Share on other sites More sharing options...
Frosty Posted April 28, 2019 Share Posted April 28, 2019 Looks just fine Max. The reason there is a cool spot between the burners is because of their orientation, they're aimed straight at the floor. Were they angled a little they would induce more a vortex rather than a general turbulence. A vortex distributes the heat more swiftly. The temperature will even out in a little while, not an issue. Keep the burners as far from the chamber as possible while still in the liner a little. burners in or out isn't an issue either. And keep the chokes where the flame is as neutral as possible, they aren't there to control temperature, they're there to control the atmosphere in the forge. See the flames in the first pic you posted? They look good. Your burners aren't inhaling exhaust or they'd be burning rich. That isn't an issue. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
MaxwellB Posted April 28, 2019 Author Share Posted April 28, 2019 Outstanding. Thank you all for your feedback. It's very very much appreciated! Quote Link to comment Share on other sites More sharing options...
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