Thinking new oven

golfer

Active Member
Thinking about taking the plunge into a heat treat oven. Most of what I do is in AEB-L and I'm sure I will be asking for advice on how to heat treat, but it does look fairly straight forward and doable for a non pro like me. I'm looking at the Paragon double barrel 24 and the Evenheat KO 22.5. I'm pretty sold on the Paragon based on what Ed has shared here but have a few questions:
1. The Evenheat indicates it goes to 2400 degrees and the Paragon 2350. However the Paragon is rated at a much higher wattage. Do you think the Paragon heats up faster, and does that 50 degrees make much difference or is Evenheat just rounding it up?
2. Paragon's double barrel has coils on top, do you think that would make for more even heat process?
3. It appears both Sentry3 and Tap control panels are very similar, any comments on either.
4. Evenheat offers an electronic "quiet" system, what do you think of that?
5. The Paragon is much smaller inside than the Evenheat, is a 4.25" height enough?
6. Any other thoughts or comments would be most appreciated.
 
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I have an Evenheat 22.5 Rampmaster II. 220V. Personally I don't care for the idea of coils on top at all. In a 4.5 space, it seems to me that it would be too easy to bump the coil with the blade both entering or leaving. The Evenheat allows me to cradle my blades in slots cut into a fire brick. It is my belief that the fire brick helps with a faster recovery, and reduces temp fluctuation. By a tad anyway. With coils on the roof, it would seem that it may be easy to overheat if blades are edge up. The Evenheat has its thermocouple in the center roof. I can set my blade edges directly under the couple giving a more correct corresponding heat compared to read out. In reality, you probably cannot go wrong with either oven. I like the Evenheat. Ed likes Paragon. I would not buy a Paragon after having the Evenheat. And Ed would likely not buy the Evenheat since he is comfortable with his Paragon.
 
Lead Dog; hey thanks for your reply. I found if very thoughtful and informative. I had not thought about cutting slots in a firebrick to stand the blades up. That seems like better idea thank using a cradle like the Evenheat has. I was hoping to get more replies and feedback [please don't take that wrong] as I am very new to heat treating.
Thanks again for your helpful reply.
 
Yep! Personally, I prefer Paragon kilns/ovens. :) They are a bit more money generally, but there is a reason. What most don't know/understand about heat treating ovens is that the differ in percentages of accuracy. Paragon ovens are generally in the +/-2-3% range, with other brands being 3-5 or some even 5-7. What the +/- percentage means is that the oven(s) are built to hold +/- those percentages at the set point temp. For example an oven with a +/-2% rating would hold the temp between 1989F and 1911F when set at 1950F. In general the less money you spend on an oven, the larger the percentage range.... another example... let's say the oven has a 7% variance range..... at the same setpoint of 1950F, the acceptable temp variance of the oven would be 136F either above or below the setpoint.

I've often read posts where individual purchased one of the cheaper ovens, then fussed because it wasn't "dead on".... that's normal, and the cheaper oven you purchase, the more variance you're going to get.

This is something that's not advertised about ovens.....but I managed to dig it up through research and talking to various companies who produce heat treat ovens. It's a method where by the companies have a "standard" of production quality. As with most things retail/commercial, there is a "balance" between quality and cost.......this is just the way that companies do it with heat treat ovens.

Some might cry foul about this, but... The only way the average "joe" would ever get a heat treat oven that is "dead on" accurate would be to find/purchase a "Lab Grade" heat treat oven..... and the majority of those START around $10K.

Long story short, for the general public, as of right now, Paragon makes the ovens which hold the tightest percentage of error...... that's the big reason I prefer their ovens.
 
Ed, I was hoping you would have something to say about the Paragon thank you for the information on accuracy. So the Paragon has more built in accuracy than the Even Heat, that is good to know and answers an unasked question. Would you address my concern regarding the 41/4" height of the Paragon and if that might be a concern. With the blades propped on edge or even on their side, they can get very close to the upper heating element, I'm not concerned about shock as some have voiced, but the damage to the element while moving the blades in or out of the kiln, or being too close to that top coil. Can you share any thoughts relative to this?
Thanks for sharing Ed, best wishes.
 
I personally prefer the smallest chamber that will fit the maximum size of any blade(s) I intend to heat. My logic was learned through building/using salt tanks. With my first salt tank setup, I used a 4" ID tank, and had a difficult time maintaining tight tolerances in the temp. After talking to a number of individuals about it, I came to realize that because there was so much thermal mass involved, it was always "chasing" itself.....when the burner would shut down, and the temp fell enough to kick the burner back on, the temp continued to fall for nearly a minute before it started to go back up again.....just the reverse would happen when it reached the set point....the burner would shut off and the temp would continue to climb, generally way past the set point. It seemed no matter how much experimenting I did with the upper and lower set points, I always had a 100+ variance above the set point, or below it. The next tank I built, I made 2" ID, and long story short, with everything else being the same, the salt tank now holds within 12F above the setpoint, and within 15F below.

I use that same logic when it comes to forges or heat treat ovens..... the smaller the volume you have to heat, generally the tighter the temp tolerance you can hold, assuming that all the components are properly sized for the application. I've never asked the question, but I suspect the smaller chamber size of the Pargon ovens has something to do with them holding a tighter percentage variance then some of the other brands, which have larger volume chambers. I've owned a couple of the other brands of heat treat ovens, but for me, none of them has satisfied me as much as the Paragon ovens. That's certainly not bad mouthing any of the others.....many folks use them, and love them, I'm only speaking for what suits me best.
 
Thanks again Ed for your valued input.
Do you find the 4.25 height of the oven to be a handicap? I'm not sure which oven you have, assuming your oven is only this height, could you share how you have dealt with this limited height?
Thanks again for your help.
 
I'm not understanding what you mean by dealing with the limited height? For me it's never been an issue. Whenever I place blades in the oven, it's always horizontal, on a rack that's made of a 1/2" section of soft firebrick with ceramic rods in it for the "racks". That still gives me 4" for the width of a blade, and I never make anything that wide. I guess if a person needs a bigger/taller area, you might have to go to an Evenheat or similar oven.

My oven is the KM18D Paragon.....all the heating coils in my oven are recessed into the lining.....so I never have to worry about "bumping" them. Is there something I'm missing or don't understand about your concerns?
 
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Ed, I don't know how you get any work done answering our dumb questions. Bless you. I believe you answered my question on how you deal with the kiln height. You still end up about 3" away from the ceiling coil. I'm guessing you can do 4 or five knives at a time like that.
Guess it's time to order my double barrel. If you think of anything else please throw it in as I am new to heat treat. Thanks much.
 
OK! WOOT! I was wracking my brain, re-reading your posts, and trying to figure out what I was missing. I wish I could get more work done....but since there's a computer in the shop, I spend far more time on the forums then I should! :)
 
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