DIY Heat Treat Oven Power, Efficiency, Electrical Question

R

ron2k_1

Joined
Sep 5, 2023
Messages
5
Hi, newbie here. Like most beginners, I'd believe, I'm contemplating more precise ways of heat treating knives. I'm in the "serious" planning sessions and before ordering anything, I want to have a build and wiring plan. I've watched every possible DIY video and D Comeau's blog, and the wiring, in my opinion, is pretty basic and not hard to replicate. However, I'm no electrician, and the maths behind the specs gives me some concerns. This is my desired physical and electrical properties (I'm not sure if this site hosts images, but I've provided a google photos link that is safe to click on as well if needed)
<blockquote class="imgur-embed-pub" lang="en" data-id="a/9UnbiSE" ><a href="//imgur.com/a/9UnbiSE">Heat treat oven specs</a></blockquote><script async src="//s.imgur.com/min/embed.js" charset="utf-8"></script>

Rony's Oven Properties Pic

So, my questions are:
1. Should I aim for a different wattage or configuration? 17,000 watts per cubic foot is almost 3 times as much as commercially available ovens of the same size.
2. What is the repercussion if left as is?

I have a 200 amp service entrance in my house, and I have several 220/240v outlets in my shop (attached to my house) wired with 10 AWG to breakers with varied amperages.

Thank you

Ron
 
Welcome Ron. Fill out your profile so we know where you live and a bit about you. It helps us give better answers.

You can build oven or make knives.
It is not all that much more, and much faster, to buy a good commercial knife HT oven from Paragon or Evenheat.
 
Yep. I'm familiar with that saying very much. But in this case, the cheapest 18", 3200 watts oven from either company is $2600. So far, my list of materials is about 700, but that excludes metal for the frame, welding supplies, etc, which I have a lot of. The thing is, I don't want to kill myself or burn down the house with what I'm trying to make.

Ron
 
Both are possible. If you don't know how to build one without risking doing that then the extra money could be considered well spent.
You will also need to be able to program the oven. Some oven builds last 6 months. That is also time you could be making knives. Also, materials lists seem to magically grow once you start the project.

Not saying "Don't do it!" just advising of what's ahead.
 
Thanks for all the advise. It is a conundrum and sucks to be broke indeed. This is just the planning and acquiring stage. I'm pretty sure, I'm about a year out before I log the first hour of this build, if I get to do it. Our ancestors quenched without kilns, I'm pretty sure I can continue with my guesstapo methods. Not like I'm selling anything, and this build's budget is also competing with the plan of one day acquiring a 2x72 grinder.

So in conclusion, so we can close this thread off, if you look at my plan pic, the 17 kilowatt per cubic foot is efficiency. I found out that the higher the number, the more efficient the oven is presumed to be for a specific power consumption rating. So for now, I'll work with those figures and start acquiring the materials in the next several months and put them up until I'm ready to start the build.
 
ron2k_1 said:
Hi, newbie here. Like most beginners, I'd believe, I'm contemplating more precise ways of heat treating knives. I'm in the "serious" planning sessions and before ordering anything, I want to have a build and wiring plan. I've watched every possible DIY video and D Comeau's blog, and the wiring, in my opinion, is pretty basic and not hard to replicate. However, I'm no electrician, and the maths behind the specs gives me some concerns. This is my desired physical and electrical properties (I'm not sure if this site hosts images, but I've provided a google photos link that is safe to click on as well if needed)
<blockquote class="imgur-embed-pub" lang="en" data-id="a/9UnbiSE" ><a href="//imgur.com/a/9UnbiSE">Heat treat oven specs</a></blockquote><script async src="//s.imgur.com/min/embed.js" charset="utf-8"></script>

Rony's Oven Properties Pic

So, my questions are:
1. Should I aim for a different wattage or configuration? 17,000 watts per cubic foot is almost 3 times as much as commercially available ovens of the same size.
2. What is the repercussion if left as is?

I have a 200 amp service entrance in my house, and I have several 220/240v outlets in my shop (attached to my house) wired with 10 AWG to breakers with varied amperages.

Thank you

Ron
Click to expand...
17000 watts in 18 x 4 x 4.5 inch HT oven ??? The question is whether there is room inside to place those 17000 watts coils :)
Look in this thread .......................... https://www.bladeforums.com/threads/heat-treat-oven-wip.1407817/
 
Stacy E. Apelt - Bladesmith said:
Both are possible. If you don't know how to build one without risking doing that then the extra money could be considered well spent.
You will also need to be able to program the oven. Some oven builds last 6 months. That is also time you could be making knives. Also, materials lists seem to magically grow once you start the project.

Not saying "Don't do it!" just advising of what's ahead.
Click to expand...
6 months to build HT oven ????? Sure , if you make your own bricks , your own PID controller and Kanthal wire ......
Come on Stacy , it is work for just the weekend /Saturday, Sunday/ if you have all the necessary parts at hand
 
Thank you Natleck. I read JT's thread before coming up with my design. His design is definitely a 6 month's WIP. Those top coils over ceramic are pretty cool too, but I'm not sure it would be more efficient than coils on each side wall. I don't know enough to go outside the norm...

I hear you on the 17 kilowatts. It is a ridiculous high figure indeed, but if you notice that is just 3200 watts on 240v packed in a W4xH4.5xL18 inch oven. I may increase the height to 6 inch, and reduce the coil length to 19.2 ohms (at 12.5 amps) that would make the oven a 1/4 cubic ft. and the watts per cubic foot change to 12 kw. I have no idea if I'm making it worse or better to entertain these changes. I'm making it costlier for sure as I'll have to buy few more bricks.
 
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