Whiskeymike Posted May 18, 2020 Share Posted May 18, 2020 Searched around, but didn't find anything specific info on the subject. I'm about to apply Plistix to the inner face of my forge and wondering if I should apply a thin coat to the face of the ribbon burner. I don't see how it could hurt as long as it doesn't restrict the holes. Also hoping that it will keep the plenum cooler as it got pretty warm in the test firing. Quote Link to comment Share on other sites More sharing options...
j.w.s. Posted May 18, 2020 Share Posted May 18, 2020 It probably wouldn't hurt like you said, but it probably won't do too much over the long term either. The volume of the plenum and the thickness of the refractory orifice would be where I would look if it's getting too hot in the first place. While the ITC may do something initially, it's still part of the burner situated very close to the firing chamber, by nature it's going to get a fair share of residual heat. When I did my old bottom blast ribbon burner a few years back I cast the ribbon at 3.6250" thick with Vesuvius 3000F refractory cement and I'd like to say the plenum itself was another 3.5"x3.5"x8" - it still had some issues if I ran it for more than 2 hours straight at forging temps. Also look at the fuel injection volume vs air, if it gets too hot inside the plenum without enough air to cool it down you can get ignition inside the plenum itself, so over engineering it in the first place isn't a bad idea. -J Quote Link to comment Share on other sites More sharing options...
Terrance W Posted May 18, 2020 Share Posted May 18, 2020 Speaking of the plenum for a ribbon burner, what are you guys using for the plenum? I was toying with using ABS or PVC for the first half then go to iron pipe closer to the forge, however I'm concerned about static charge building up from the air flow in the "plastic pipe" and sparking off and causing a pre-ignition or worse. Quote Link to comment Share on other sites More sharing options...
Whiskeymike Posted May 19, 2020 Author Share Posted May 19, 2020 4 hours ago, Terrance W Winder, GA said: Speaking of the plenum for a ribbon burner, what are you guys using for the plenum? I was toying with using ABS or PVC for the first half then go to iron pipe closer to the forge, however I'm concerned about static charge building up from the air flow in the "plastic pipe" and sparking off and causing a pre-ignition or worse. When I refer to the plenum, it's the box that holds the refractory burner edge, not the tubing to it. My plenum is made from 16g steel bent to a box with a short 5" steel tube coming out of it to connect to the air/gas line. Connected to that, I'm using flexible 2.5" auto exhaust tubing that's about 5' long (2-2.5' too long, will cut it when I figure out a permanent stand to hold the forge). Then it connects to an air gate, and that is connected to the blower with a silicone 2.5-3" coupler made for cool air intakes for performance cars. I think you could use plastic near the blower, but I think you just have to figure out the advantages. I tried to keep mine as simple as possible. Quote Link to comment Share on other sites More sharing options...
j.w.s. Posted May 19, 2020 Share Posted May 19, 2020 I personally wouldn't put plastic anywhere near it just because of heat issues and the fact that the air and fuel mix pre-plenum. All of the ribbon burners I've made have used square tubing for the plenums, but bending a box could probably be the easier way to go about it if you have the tools for it. Everyone I've made has been a blower on a reostat to black iron pipe, then a 45 degree elbow with the propane injection nozzle aimed down towards the plenum in the direction of air flow. From there I have done them with and without baffles inside the plenum. I seem to recall many years ago a talk on making crayon burners that had a formula on number of 23/64th (if you leave the paper on, 5/16th's without? It's been a while) holes in the burner vs volume of plenum and air flow/pressure. Frosty might have been part of it, so maybe he'll jump in here. I know he's got a huge thread that I lost track of/not caught up on that is dealing with a naturally aspirated ribbon burner design - he definitely knows more on the subject than I do. I did find a post I made in 2013 on the subject but the pictures are long gone. -J Quote Link to comment Share on other sites More sharing options...
Terrance W Posted May 19, 2020 Share Posted May 19, 2020 Then for the lack of a better term, I'll call it a feed pipe, I've not been able to get my paws on any 2" black pipe, the commercial suppliers have a minimum quantity or will only sell a full 28' stick. when I need is maybe 5 feet or so after cutting and threading. I don't have a welder so dose the plenum get to hot to braze it or for 40% silver solder? Quote Link to comment Share on other sites More sharing options...
j.w.s. Posted May 20, 2020 Share Posted May 20, 2020 I'd braze it with nickel silver, that melts at 1670F-ish I believe. Home Depot carries 2 in black iron and they will cut and thread for you as well, it's around $45 for 10 feet, never hurts to have the extra sitting around the shop for various other projects in the future.. I was just looking for some to make some holders for my pin stock rods that are too long for my pigeon hole shelf, could have sworn I had 4 or 5 feet, haven't tripped over it yet but this is how I'll end up with 8 feet of it lying around this summer! -J Quote Link to comment Share on other sites More sharing options...
Brandon Ade Posted February 13, 2021 Share Posted February 13, 2021 OP, FWIW I brushed on ITC-100 to my ribbon burner face without issue. Just keep the holes clear, use a toothpick or q-tip to clean them out quickly after brushing. Quote Link to comment Share on other sites More sharing options...
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