Learning the difference between ovens and furnaces with John Bouley of Furnace Brokers International. #BlackbirdTV
About this segment of Blackbird TV
Recorded: February 24, 2021
Published: August 31, 2021
Joining us today on Blackbird TV’s John Bouley from Furnace Brokers, John is an expert in in furnaces and ovens and in all things heat treating John. Thanks for joining us. Oh, thank you for inviting me. I’m glad to be here. I wanted to ask a couple of questions. Again, it’s it’s the the famous question of what’s the difference between an oven and a furnace. John, can you briefly just describe what that is for us? So an oven is sheet metal construction sandwiched around insulation. So it’s very, very light duty. A furnace is steel construction. And the interior could be brick or a lightweight fiber, but it’s very, very heavy duty construction. OK, so I’m going to ask you to compare these two heat treating machines, I’ll call them for now, this first one is a Wisconsin. And if you look at this, it’s big, it’s steel, and it’s got a belt on it. Is this thing an oven or is this a furnace? This is an oven for a couple of different reasons. One, the temperature, according to the data tag, is a maximum of five hundred, which would put it in the oven category. This is sheet metal construction, which which defines it as an oven. And the next one, it’s a Sinterite belt furnace. And this runs at a very, very high temperature, well over 2000 degrees. And this is the entrance to the furnace. And again, a furnace is heavy duty construction. So this is the the parts to be sintered being put in. Sintering is you basically take powder. And you form it into something. Now, in this case, it looks like there’s some kind of gears when it goes through the furnace. It basically melts this powder that’s been compacted and it makes it a solid piece of steel. When it was first introduced years ago, the auto companies were with the clients and they wouldn’t buy it. Because they were so afraid of that powder just breaking. You can’t make that you can’t make it as strong as a regular piece of steel. That’s impossible. And it took a lot of heavy selling. But if you can imagine, if you had to machine, all of those gears, how much labor, how much wasted material So this this sintering is is a big deal, an industry. So anyway, back to this furnace. This is the entrance. And once it’s been heated and whether it’s sintering, whether it’s annealing, whether it’s hardening, it has to be cooled down. Some products, you can just take the belt right out and let it air cool. But in this particular one, what you see is the exit end of the same furnace and. Prior to that, to where the open belt is, that’s a cooling chamber, so it’s a double walled chamber That’s water cooled. So the parts are, say for conversation sake, 2000 degrees coming out of the furnace. And by the time they end up outside the furnace, they’re room temperature. So the belt is traveling very, very slowly through. But it goes through this water jacket, a cooling chamber to get cooled down. And and then it comes out to be unloaded or dumped into this bucket. Yeah. On this big furnace as the appraiser. What are the parts that I want to measure, understand write down and put into my description for this sintering furnace. On any furnace. The inside working dimensions are critical. So in the case of this, you just measure the belt. How wide is the belt? But as important is the height above the belt. In other words, how much could you fit through the… How much goes through the gap? How many how many pizzas can you put in? Usually, they have it like in this particular case. They have a exhaust stack there. But if you notice, they’re limiting how much can come through there So that would be a good thing to measure. In other words, it looks like it’s three or four inches high. So whatever it is, you say three inch high because, you know, you can’t get anythin higher through there. And then you want to measure the heated lengths in this particular type of furnace. It’s kind of difficult because sometimes it’s not really defined with the heated like this. So if nothing else, just measure the box itself. How long is this thing? Long as the box. Just the box. Right. And if he said, well, the box is eight and a half foot long, I might make the assumption I have to look into pictures that the hot zone is probably eight foot long. And the length of the cooling would be good to have. But it’s not critical. What’s more important is the heat. You know, the with the length and the height, right? Whether it’s gas or electric. OK. And the maximum temperature is always critical, if you can find. You know, when dad attacked because furnaces run all over the place and the higher the temperature. The more they’re worth. So it’s kind of critical. And but the most of the furnaces you’re going to run into are 2000 degrees on down. The ones that operate above 2000 start to come into a little special place where, you know, above a certain temperature. They have different types of heating elements. They have different types of probes. It gets much more complicated. So the maximum temperature is critical. The biggest mistake is saying, well, the temperature control goes up to twenty four hundred. Yeah. The controls come out of the factory to to fit a bunch of different furnaces. So if the control goes up to 2400, that means nothing. This could be an eighteen hundred degree furnace. So be very, very mindful of that. Good. Protip. One tip. Go. This is what they call lead wire. That comes from the temperature control to the probe that’s in the furnace. If you’re ever looking at a furnace. That has a green lead wire. The probe inside that furnace, it’s actually feeling the temperature is made out of platinum and one probe. To a scrap yard will bring over a thousand dollars. Well, there’s a pro tip for you auctioneer’s out there. Let’s look for those. Green means money! Green means money. Wow. Yeah, we’re getting nuggets of brilliance today, John. So it’s it’s platinum. And and basically, if you just took that probe out, it’s like. You know, the size of my my glasses here, it’s really thin, thin wire two wires, even thinner than this. Two wires going in and it’s a thousand dollars just for scrap. So to buy that is two or three thousand dollars. Is that something that you can reuse? Let’s say that the whole furnace is scrap, but the probe is OK. Does that mean that the salvage value of that we’ve still we got we’re starting at a thousand dollars just for the probe? Probably. Fantastic. Brilliant. Really good information. Let’s go back to this Wisconsin real quick, because we’ve we’ve talked about the furnace and now… the Wisconsin it you know, to a layman, it looks the same. It’s big. It’s got a belt. And this is not a furnace because of the temperature cham It only goes to five hundred degrees. So that means it’s an oven. That means it’s an oven. Operate at 500ºF. They don’t they’re not max tempted 500. So that would be the first clue. Right. It’s an oven. Anything. A thousand degrees on down is probably an oven. Broad statement. So this works the same way as the belt furnace you put on. You put stuff on the belt at one end and it comes out the other. But in most cases, ovens don’t have cooling chambers. They they go in and they come out. And the exit area might be extended out four or five, six feet to give the parts time to cool down in the open air as they come out. So at five hundred degrees, a thin part would cool down and three or four minutes to room temperature. On occasion, you’ll run into belt ovens like this that will have cooling chambers They may have fans blowing the air on it as it comes out, and it might be in a cooling tunnel. But most of the belt ovens that you’ll see don’t have any cooling chambers They just put it in. Take it out. And if it’s there, describe it. Last question, John. The collateral side of of why we have these interviews do these make good collateral? Can the bank get their money out of these? If there’s a problem, if they need to sell them? This is excellent collateral. On on our news side, delivery on something like this is 16 to 20 weeks, even in these times. So this is this is something that that that should sell fairly easily. How about the sintering furnace that the blue one? Does that make it collateralize a little longer? A little bigger? It’s good. It’s good collateral. It’s a little more smaller market for that type of furnace But because it’s doing sintering, it could do other processes. It is not just for sintering. So, yes, it would make good collateral. Good information, and I really appreciate your expertize, John Thanks for joining us today. Oh, glad to be here. Thank you very much.