diy heat treat oven

C

CTrelichunter

Joined
Jul 11, 2020
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hi im new to the forum my name is mark i just built a heat treat oven inside diameter are 22inches deep 9.0in wide and 7.0in tall i was looking at oven specs online that had the same dimensions to get a idea of what coils i would need and wattage i dealt with kilnparts.com they helped me with the elements i ended up buying 2
Kanthal A1 Element – 240 Volts, 16 Amps, 3840 Watts 16 gauge i wired them in parallel i used 2 ssrs inkbird 40DA when i turned oven on and checked with my meter it said 33 amps!!! i called kiln parts and asked the guy there if that is ok he said the elements are rated for 33 amps seems awfully high to me can you give me your input if possible i dont want to burn them up i paid alot for them i should have made my own live and learn i guess any advice would be great thank you do i need to just use the 1 element ?
 
Hello Mark, and welcome to Bladeforums. If I understand your description correctly, I wouldn’t be surprised to find that (2) 16 amp elements wired in parallel are drawing 33 amps. It could be useful to control them independently. Sounds like a neat project.

Parker
 
catspa said:
Hello Mark, and welcome to Bladeforums. If I understand your description correctly, I wouldn’t be surprised to find that (2) 16 amp elements wired in parallel are drawing 33 amps. It could be useful to control them independently. Sounds like a neat project.

Parker
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what i need to know is how to get this oven to run on 16 amps is the 33 amps to much and are the elements gonna burn up ? should i just run the 1 element? im asuming if im drawing 33 amps then my watts are way to high as well? im not good with electrical im asking for some advice as to what to do thank you
 
CTrelichunter said:
what i need to know is how to get this oven to run on 16 amps is the 33 amps to much and are the elements gonna burn up ? should i just run the 1 element? im asuming if im drawing 33 amps then my watts are way to high as well? im not good with electrical im asking for some advice as to what to do thank you
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You have 16.5 amps going through each element. You add 16.5 plus 16.5 and you have 33 amps total. That's what you should get wired in parallel. When you wire resistors in parallel you halve the resistance of the circuit, so then the amperage doubles. ( Your heating elements are just a kind of resistor.) When you wire resistors in series, you double the resistance of the circuit, and so your amperage is halved. So if you were to wire them in series, you should measure about 8 amps.

O.B.
 
Mark, it's highly unlikely that your elements will burn up. However, you should verify that you have enough branch circuit to power your oven in the way you have it wired. That can keep your house or shop from burning down.

Wired as you describe, I would use no smaller than #8 copper wire for the phase conductors, and a breaker no larger than 40 amps on a dedicated circuit shorter than 100 feet. If your conditions are different, make friends with an electrician and look up table 310.16 in the National Electrical Code.

Controlling your elements separately allows you more flexibility in using them. If you fire one element and it doesn't provide enough heat for your task, add the other one. Conversely, if both elements together give too much heat, back one out. That's a very simplified idea of two stage control, there are others more complex.

I can't tell you what to do because I'm not there with you to see your conditions and know how much heat you need for your tasks. Many variables are in play, including ambient temp, size of your steel items, and more. But you're on the right track to finding out, by your own experiments and observations. A properly sized branch circuit is an important part of doing that safely.

Parker
 
I don't think the elements are in any danger of burning up, assuming you have them stretched and installed properly. Make sure your SSRs have proper heat sinks, otherwise they are likely to burn up at some point. I ended up installing a fan in my control box to keep it cooler. You should make sure you check your circuit like catspa said, and use the correct wire gauge for all your internal wiring. I used a breaker as an on/off switch for additional protection.
 
Hmm, I posted a reply right after CT posted this yesterday. Not sure why it never posted. Anyway. welcome CT.

Your problem isn't the elements burning up. They are running exactly as they should. You have a HUGELY powerful HT oven, though. My big salt pot draws 35 amps.

Your options:
1) run a 40 amp circuit to the shop and use it - This will work, but the oven will be really powerful for the size.
2) cut the coils in half and stretch them out - Probably not a great idea.
3) get the proper coils and change them - This is your best choice.
 
Stacy E. Apelt - Bladesmith said:
Hmm, I posted a reply right after CT posted this yesterday. Not sure why it never posted. Anyway. welcome CT.

Your problem isn't the elements burning up. They are running exactly as they should. You have a HUGELY powerful HT oven, though. My big salt pot draws 35 amps.

Your options:
1) run a 40 amp circuit to the shop and use it - This will work, but the oven will be really powerful for the size.
2) cut the coils in half and stretch them out - Probably not a great idea.
3) get the proper coils and change them - This is your best choice.
Click to expand...
 
Hubert S. said:
I don't think the elements are in any danger of burning up, assuming you have them stretched and installed properly. Make sure your SSRs have proper heat sinks, otherwise they are likely to burn up at some point. I ended up installing a fan in my control box to keep it cooler. You should make sure you check your circuit like catspa said, and use the correct wire gauge for all your internal wiring. I used a breaker as an on/off switch for additional protection.
Click to expand...
thank you for your reply actually i have heat sinks for the ssrs ,also i installed a breaker 40 amp as a switch i am now running just 1 element and works great for what i will need i think im good now my amps are 16.9 makes me feel safer too!! :) i was think of doing a fan as well i have one from a old computer
 
yes thank you stacey appreciate your reply im all set now i thinkeveryone who has replyed has been very helpfull thank you again be safe Mark
 
CTrelichunter said:
yes thank you stacey appreciate your reply im all set now i thinkeveryone who has replyed has been very helpfull thank you again be safe Mark
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Could you please post what plans you have so i can learn from them? I'm building a tempering oven. I dont think its possible to run an actual heat treat oven without 220 power. Im doing my efforts in a back yard at home.
 
Tony Park said:
Could you please post what plans you have so i can learn from them? I'm building a tempering oven. I dont think its possible to run an actual heat treat oven without 220 power. Im doing my efforts in a back yard at home.
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Tony, you definitely can run one that is 120. You would have to double the amperage to get the same power though. 240 is more efficient from a material perspective.
 
Nick Curtis said:
Tony, you definitely can run one that is 120. You would have to double the amperage to get the same power though. 240 is more efficient from a material perspective.
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I suspect there is an outer bound of amperage running thru home wiring, though Im not sure what that would be or even if that is so.

i know investment finance. I know tax and estate planning and asset protection. Electric stuff.... see my diy tempering oven thread.... :-)
 
Stacy, only kitchen and bathroom circuits are typically 20 amps. The rest are usually 15 amps. Garages are usually on a 20A circuit because the builder only wanted to use 1 GFCI so the circuit is shared between the garage and bathrooms.

15 Amps is far more common. You should only load a circuit to 80% of capacity.

What all of this means is that if you are running a kiln you probably need a new circuit (unless you stay at 1,440 watts or less), so you might as well make it a 240v circuit.
 
thanks for the reply tony i really dont have any plans i did alot of you tube resaerch i built mine as i went you will need at least 20-25 soft fire bricks i bought a bunch of mine on etsy i will find you the link they were shipped out really fast good people i dealt with and my ssrs and pid and other materials mostly from amazon what ever you need i will be happy to help you with just reach out to me also check this blog out http://dcknives.blogspot.com/p/electric-forge.html very usefull here is the link to the fire bricks they are very good bricks


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Hello, Tony. Residential wiring is less complex than investment planning and asset protection, so you're in good shape for learning it. Just takes some study to understand.

Generally speaking, electrical demand has increased over the last century or so. A house built before 1920 was probly wired with one light and one outlet in each room. People today use many more electrical devices than that kind of wiring will support, and the National Electrical Code has been enacted to specify which methods and materials are safe and approved.


Somewhere in or on your home is an electrical distribution box called a panel. There are some big wires coming in, and smaller wires going out. Your local utility provides voltage to your panel through the big wires, called service entrance conductors. Somewhere nearby you also have a metering device and a disconnecting means. The SE conductors are connected most often to vertical buss bars, which provide a certain number of spaces for breakers to connect. Breakers are overcurrent protection devices, and each one controls a particular branch circuit. The wire size of each branch circuit determines how much amperage it can safely carry, and it's breaker is sized accordingly. Each circuit should be labeled as to what it serves, and in the best installations the terminal wiring is labeled as to which circuit serves it. So each circuit has it's own limit, and there's also a limit on the total current that can be drawn through the service. Exceeding either of those limits will overheat the wire under certain conditions, and if the safety devices fail that can cause damage up to and including burning your house down and killing everyone in it. Obviously, it's very important that our dwellings be wired safely in the first place, and that additions or modifications to the electrical system don't compromise it's safe operation.

Information about branch circuit sizing and electrical safety in general is readily available, and a homeowner can certainly perform their own work. But it's not something you can blunder through and hope for the best. If you're unsure, there's no shame in hiring an electrician and asking him/her to explain the process. I urge you, please: don't overload a circuit. Don't upsize a breaker to accommodate overloading a circuit. Do double check all your connections making sure they're clean and tight. Best of luck to you.

Parker
 
CTrelichunter said:
hi im new to the forum my name is mark i just built a heat treat oven inside diameter are 22inches deep 9.0in wide and 7.0in tall i was looking at oven specs online that had the same dimensions to get a idea of what coils i would need and wattage i dealt with kilnparts.com they helped me with the elements i ended up buying 2
Kanthal A1 Element – 240 Volts, 16 Amps, 3840 Watts 16 gauge i wired them in parallel i used 2 ssrs inkbird 40DA when i turned oven on and checked with my meter it said 33 amps!!! i called kiln parts and asked the guy there if that is ok he said the elements are rated for 33 amps seems awfully high to me can you give me your input if possible i dont want to burn them up i paid alot for them i should have made my own live and learn i guess any advice would be great thank you do i need to just use the 1 element ?
Click to expand...

Probably one of the longest run on sentences I have read lol.

I haven’t see a 15amp breaker in forever. Most places have switched to using 20amp and running less circuits if cost is an issue.

As for your elements I would consider 16ga on the lite side for heat treating ovens. I use 13ga and it has never failed me. I Run it for around 5hrs+ every day for 3-4years.
 
Nick Curtis said:
Stacy, only kitchen and bathroom circuits are typically 20 amps. The rest are usually 15 amps. Garages are usually on a 20A circuit because the builder only wanted to use 1 GFCI so the circuit is shared between the garage and bathrooms.

15 Amps is far more common. You should only load a circuit to 80% of capacity.

What all of this means is that if you are running a kiln you probably need a new circuit (unless you stay at 1,440 watts or less), so you might as well make it a 240v circuit.
Click to expand...

Maybe it is my home and shop, but I have no 15 amp circuits. Everything is wired with 12 gouge and larger wires.
 
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