Heat Treat Oven Element

Easy guys, remember that this is the most friendly forum on the WWW. This ain’t no car forum
 
And speaking of heat treating elements... I just fired-up the furnace for the first time in over a year. It's a home-made box and I'm hoping the element holds-up. I've got 2 sizable piece of 1045 that need to heat soak for 2+ hours. At least the shop will (hopefully) will be a little warmer today.

Stay tuned... FYI: The project connected to this is over here: http://hobby-machinist.com/threads/bull-nose-live-center.64859/

... Back to regularly scheduled programming.... And remember... try to be chilled even when heat treating.
 
So I decided to put the oven back together and just jumper the two bad elements with a few strips of 10 AWG solid. Seemed to be working well. At 1650°F I noticed a really hot hot spot and the ceramic was melting.
thumbnail_IMG_20171230_141239409.jpgThis oven is old. From the seventies I think. I can probably keep the shell and rebuild it with proper heating elements. It's colder than a well diggers toolbox out there today. May have to wait till spring.
Edit: Thanks for the suggestions on trying to fix the elements
 
Last edited:
OK time for this one to be watched. If you are going to ask a question you should listen to all the answers. Please also refrain from bashing no matter how slight. Name calling is a no-no on this form. I don't wish to see this thread get locked.

"Bill Gruby" Global Moderator
 
Last edited by a moderator:
ddickey said:
So I decided to put the oven back together and just jumper the two bad elements with a few strips of 10 AWG solid. Seemed to be working well. At 1650°F I noticed a really hot hot spot and the ceramic was melting.
View attachment 252510This oven is old. From the seventies I think. I can probably keep the shell and rebuild it with proper heating elements. It's colder than a well diggers toolbox out there today. May have to wait till spring.
Edit: Thanks for the suggestions on trying to fix the elements
Click to expand...

I'm surprised the copper wire worked as long as it did. Question: Was bringing it up to 1650 just a test? That's seriously hot for most heat treating work unless you're working with some tool steels or are normalizing medium or high carbon steel.

A couple other tips... When you open the door, power it off first. The inrush of air causes severe thermal shock to the elements (and everything else too) and leads to premature failures.

BTW: If that were mine, I would just make my own kanthal coils and string it to the sides of the plates you have in there with heavy stainless steel wire (aka: SS safety wire).

If you know the basic electrical specs of the box (rated voltage and wattage) you can reverse-engineer the coils for it. What are the electrical specs out of curiosity?

Happy New Year...

Ray C.
 
Yes. Just a test. A little to high.
I didn't know about opening the door, thanks. When I turn if off I always leave the door shut.Not sure if that is proper or not.
The copper wire didn't seem hot at all. It was used in the back to jumper the two bad elements. Was that a bad decision?
Not sure but a later model's specs are 240v, 9.3A for 2.23KW.
 
ddickey said:
Yes. Just a test. A little to high.
I didn't know about opening the door, thanks. When I turn if off I always leave the door shut.Not sure if that is proper or not.
The copper wire didn't seem hot at all. It was used in the back to jumper the two bad elements. Was that a bad decision?
Not sure but a later model's specs are 240v, 9.3A for 2.23KW.
Click to expand...

Closing the door after "a heat" (as it's called) is fine. The less the coils get exposed to air and all the contaminants thereof, the longer they will last.

Pure copper has a pretty high melting temperature but common wiring is almost certainly not pure copper. It worked I guess and that's all that counts.

Take a mic or caliper and measure the diameter of the existing heater wire. I'm guessing it will be around 20 thou in diameter. Let me know and I can tell you what wire to get and how long to make the coils. I can't make any guarantees because I can't see exatly how it's wired but, since it's 240 volts and fairly low wattage, you probably have 2 coils in parallel. FWIW, the smaller of my two ovens is 8500W and the big one is 12kw.

Ray
 
Makes sense Latinrascalrg1.
Size is .0565"
Refer to post #16. That diagram looks like a series connection.
I could be wrong on the wattage. I can not find any info. The above was from a newer model.
 
Ray can you add a shielding gas to the oven during a "heat" cycle that would help protect the elements and metal projects from oxidizing?
 
You must log in or register to reply here.
Back
Top