Looking for Info. WTB: heat treat oven

What do y’all think of this? I found it on eBay. Certainly looks handmade but do you think it would work (get hot enough)?

His description for the item: DIY heat treating furnace. Used to harden tool steels. temperature will reach in excess of 1700F. 9.5" deep, 9.0" wide, 5.0" high. operates on household 220VAC. Digital temperature controller. Extra long power cord.
 

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Taz said:
I would pass on that one. The elements look shot and it may not get hot enough for AEB-L and may not fit a 12" blade well in it.
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Ok, could the elements be replaced?
 
They can, but that looks like its in rough shape
 
Taz said:
They can, but that looks like its in rough shape
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You mean the overall body of it? I just kind of like the price:) $200- shipping to me. He said that diagonal it is 12 inches long. So far I haven’t even made a knife 12 inches long…
 
The walls on the inside look rough as do the elements. The coils are coming out of the grooves, which means they weren't held in place very well. I dont know why the pid shows -8.7???? I would do a hard pass.

For about $400, you could build up something for 110v that would work better. 16-20 bricks (k23 soft insulating fire bricks), an element, pid, thermocouple, ssr/heat sink, some wiring and you could do a nice, basic heat treat oven. Look up some DIY HT oven builds.

Going diagonal with the coils right there is dangerous; you could short something out.

I see 14" diameter kilns, 6" deep on FB Marketplace often for around the same price. Add a pid, thermocouple, ssr/heat sink and basic wiring/enclosure for the control box and you would be much better off.
 
Taz said:
The walls on the inside look rough as do the elements. The coils are coming out of the grooves, which means they weren't held in place very well. I dont know why the pid shows -8.7???? I would do a hard pass.

For about $400, you could build up something for 110v that would work better. 16-20 bricks (k23 soft insulating fire bricks), an element, pid, thermocouple, ssr/heat sink, some wiring and you could do a nice, basic heat treat oven. Look up some DIY HT oven builds.

Going diagonal with the coils right there is dangerous; you could short something out.

I see 14" diameter kilns, 6" deep on FB Marketplace often for around the same price. Add a pid, thermocouple, ssr/heat sink and basic wiring/enclosure for the control box and you would be much better off.
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Thanks so much for the advice. I’ll do exactly what you said- pass on this one. I’ve been watching some videos on how to build one and it sure doesn’t look THAT hard. I think I can do it it…
 
Figure out the power you have available to you (110v or 240v) and what amperage you can draw. You want around 4000-5000kW per cubic foot of volume as well so it heats fairly quickly.

3 bricks will get you 13.5" long chamber and you can cut the bricks to overlap them a bit so you can reduce your volume of the inside dimensions. 6" wide, 5" or so tall and 13.5" long will give you around .25 cu ft and should heat pretty quickly, even on 110v.
 
Taz said:
Figure out the power you have available to you (110v or 240v) and what amperage you can draw. You want around 4000-5000kW per cubic foot of volume as well so it heats fairly quickly.

3 bricks will get you 13.5" long chamber and you can cut the bricks to overlap them a bit so you can reduce your volume of the inside dimensions. 6" wide, 5" or so tall and 13.5" long will give you around .25 cu ft and should heat pretty quickly, even on 110v.
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I only have 110v available to me. Is there a list of links anywhere online that I can look at for exact prices?
 
We aren't supposed to post links that aren't advertisers.

I would look for a local pottery/kiln place, repair shop, etc for the fire brick. They are super expensive to ship (sometimes as much as the bricks themselves!) and there are ones from China that are much heavier/denser and slower to heat up, so you want to get good ones! Morgan Ceramics, BNZ, Lynn seem to be good USA based manufacturers/suppliers. Stay away from any imported from China at this point. Amazon has lots of the cheap, heavier bricks and some of the good ones, but it's hard to tell. I made that mistake the first time!

Elements, many wind their own, but you may be able to find a premade kiln element that works for you. Kiln Parts and DuraLite are 2 suppliers I have used in the past and can also make a custom element for you. You will need to stretch it out to the minimum length most likely, so you will need to know the length you need for the resistance, voltage, amps, etc. This will take some planning!

I went the route of using fused quartz tubing across the top of my kiln so I could use the element going around the tubing across the chamber instead of putting the elements into a groove in the wall. I was able to use much thicker gauge element wire, and pack more of it into my kiln. Most people are using 14-16ga wire for their elements, but resistance/length/amp/wattage all need to be calculated to fit your oven. The groove in the wall is a bit simpler to do; I had to make a jig to make the element zig zag across the top of the kiln chamber, and cut glass tubes for the element to go over.

Pic from when I was building my oven with the element coils across the top:
tEK5w2C.jpg


PID, SSR, Thermocouple I purchase from Auber Instruments, but they are also available on Amazon as well from Auber and other brands.

oven.
 
What about this? Does this look like a good purchase for the price $791.
DOMESTIC, SINGLE PHASE, 110V-240V KILN 1100 C (2012 F) WITH 11.6 C/L CHAMBER
 

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If you only do smaller knives in the 5-8" range that is fine size-wise.

I can tell you that the top temperature listed is usually not realistic, but it should reach normal stainless HT temps ... eventually. For carbon steel it will be fine.

When I plug your description into the big A it shows what I guess is the one you are looking at. Reviews are not stunning, but that was mostly ssupport issues. Caveat Emptor.

It probably is the best for a starter oven in your budget situation.

I always suggest buying an Evenheat or other brand from a knife supply like USA Knifemakers and you know that it is a good oven and will have great customer support. However, I understand that that is m=not in everyone's budget in the beginning.
 
So I am going to try to build one after all. I think it will be good for me to try! Can anyone tell me exactly what PID, SSR, thermocouple, and element I should get? Also, I’m thinking about getting the k23 bricks from hightempinc.net. Are those a good option? I’m going to try to make it the dimensions that Taz posted above. 6" wide, 5" or so tall and 13.5" long. What gauge of kanthal wire should I get? I’ve looked at a lot of the threads on here but nobody seems to be building a 110v so I can’t see exact answers. Thanks for your help, Linus
 
Use the custom Search engine in the stickys. It will find you dozens of HT oven build threads and discussions. Use search terms like "HT oven Build" and HT oven PID" etc.

There is a build thread probably every month.
 
Does any of this stuff look right? I’ve researched and looked through every thread here but I just want to make sure before purchasing… 1726882058299.png
 
I'd pick a 40-amp SSR, but otherwise it looks OK. The SSR will cycle thousands of times and the higher the rating the longer it will last.
 
I agree with Stacy; higher amp SSR, but everything else looks good and is what I have used! (except I have an Auber WiFi Ramp/Soak PID, but I was eyeing the bluetooth one!) Bricks from High Temp are good ones!

For the element, I would see if 14 ga would work? 16ga, people had longevity issues with it depending on the temps and frequency you are using it. 14 ga will last longer if you can fit the element coil length in your build.
 
Thanks. I ordered all the stuff and it has been coming over the last few days. Can anyone explain to me the wiring for the N20K48 PID I ordered? I cant find any specific videos on this specific pid and the manual isn’t very clear either.
 
Page 9 of the operating manual covers the wiring pretty well, though the symbol for a thermocouple isn't obvious unless you know: looks a bit like clock hands at 8:20.

Thermocouple connects to terminals 2 and 3. DC pulse output to the SSR from terminals 5 and 6. Power in on terminals 8 and 9. If you are using an alarm relay, you have Volt-free contacts on terminals 6 and 7.
 
I note you don't have thermocouple extension (or compensating) cable on your amazon list. You need it and you need to connect the legs correctly: Type K if you are using the type K thermocouple in the list. Anything else will cause the temperature to read incorrectly.
 
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