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Heat Treat Furnace Build
- Thread starter jbolt
- Start date
- Joined
- Jan 2, 2014
- Messages
- 9,540
Looking great, very nice design.
I appreciate you taking us along for the ride!
Thanks,
-brino
Seriously, I'm green with envy; would love to have this.
- Joined
- Nov 25, 2015
- Messages
- 10,042
Nice work. Looking good.
- Joined
- Dec 3, 2013
- Messages
- 1,848
A little more progress now that the bathroom remodel is done.
I did the enclosure cutouts today on the CNC mill. Always fun to do setups on enclosures. This enclosure is small enough I could get it rigid enough to cut full depth with a 1/8" carbide end mill.
I used some of the left over ceramic tile from the bath remodel to cover the back of the heat box where the elements terminate. The area around the tiled area will get a 1" layer of ceramic blanket.
I did the enclosure cutouts today on the CNC mill. Always fun to do setups on enclosures. This enclosure is small enough I could get it rigid enough to cut full depth with a 1/8" carbide end mill.
I used some of the left over ceramic tile from the bath remodel to cover the back of the heat box where the elements terminate. The area around the tiled area will get a 1" layer of ceramic blanket.
- Joined
- Dec 3, 2013
- Messages
- 1,848
Here is the back panel construction and installation.
Back panel cutout on the CNC mill.
The only brake I have access to does not have any dies narrow enough to do the bend so I made up a redneck bender using angle iron and some door hinges. I used a crescent wrench has a handle. Worked perfect!
One layer of 1" ceramic blanket, back panel and the 1" angle iron retaining frame. The frame locks in with set screws in the corners.
To terminate and secure the ends of the heating elements I modified some 5/16" stainless steel bolts. The element passes through the middle of the bolt and is captured by the grooves. I put kinks in the pig tails of the element wire to create positive contact inside the hole to avoid potential arching. I don't know if that would have been an issue but the instructions for the heating elements required that the coils be stretched to create a gap between the coils to prevent arcing so I figured this was a good idea.
Heating elements and thermocouple installed.
Here is my first wiring configuration. I originally had the heating element setup with a SSR on each end of the element so it would be fully disconnected when off. I had a problem with the Auber PID controller. It would not give a consistent reading from the thermocouple and after a day and a half of trouble shooting I determined the unit was bad.
I called Auber on the PID issue and they agreed it was faulty and sent me a return shipping label. That PID has been sent back for replacement. I posted about the PID issue in the electrical forum looking for troubleshooting help and during those conversations another forum member, who has been an incredible help, suggested I use a single SSR and a double pole contactor. Apparently SSRs still leak some voltage when off. I also liked the idea of being able to switch the contactor to turn off the elements and still keep the PID under power for setups, troubleshooting etc. I also decided to order another PID from automation Direct. It has the ability to be programmed from a PC.
Here is the revised electrical with a contactor, single SSR and a Solo SL4848-VR PID controller. The contactor is the type use in air conditioners. This one is 40 amp with a 240vac coil. The whole system is run on 3-wire 240vac. The PID provides up to 14vdc to trigger the SSR.
Here is a quick shot of the back panel with the elements terminated and hooked up. Last thing to make is a protective cage for the termination area.
Today I powered it up and setup the PID. I did the initial setup with the elements disconnected and with a 75w light buld hooked up to the SSR. The PID manual is not very intuitive so it took some trial and error to figure out the settings. I'm not the sharpest tool in the shed when it comes to things like this but after pushing buttons for a while it starts to make more sense.
After I was comfortable that the PID was operating correctly I hooked up the heating elements. The PID has 4 modes, PID, Manual, On/Off and Ramp/Soak. In PID mode you can auto tune the system to set the PID parameters. Currently the oven is on and set at 200 degs for the first part of the break in. The auto tune took about 10 minutes but once done the temp is holding rock steady. I will keep it at 200 overnight to burn off any excess moisture that may still be in the brick and then do the element break in and install the door gasket tomorrow.
Up and running!
The toggle switch is for the contactor, the green light is on when the contacor is energized. The amber light shows when the SSR is on and the elements are heating. The two red indicators are lighted buzzers for Hi/Low alarms.
Back panel cutout on the CNC mill.
The only brake I have access to does not have any dies narrow enough to do the bend so I made up a redneck bender using angle iron and some door hinges. I used a crescent wrench has a handle. Worked perfect!
One layer of 1" ceramic blanket, back panel and the 1" angle iron retaining frame. The frame locks in with set screws in the corners.
To terminate and secure the ends of the heating elements I modified some 5/16" stainless steel bolts. The element passes through the middle of the bolt and is captured by the grooves. I put kinks in the pig tails of the element wire to create positive contact inside the hole to avoid potential arching. I don't know if that would have been an issue but the instructions for the heating elements required that the coils be stretched to create a gap between the coils to prevent arcing so I figured this was a good idea.
Heating elements and thermocouple installed.
Here is my first wiring configuration. I originally had the heating element setup with a SSR on each end of the element so it would be fully disconnected when off. I had a problem with the Auber PID controller. It would not give a consistent reading from the thermocouple and after a day and a half of trouble shooting I determined the unit was bad.
I called Auber on the PID issue and they agreed it was faulty and sent me a return shipping label. That PID has been sent back for replacement. I posted about the PID issue in the electrical forum looking for troubleshooting help and during those conversations another forum member, who has been an incredible help, suggested I use a single SSR and a double pole contactor. Apparently SSRs still leak some voltage when off. I also liked the idea of being able to switch the contactor to turn off the elements and still keep the PID under power for setups, troubleshooting etc. I also decided to order another PID from automation Direct. It has the ability to be programmed from a PC.
Here is the revised electrical with a contactor, single SSR and a Solo SL4848-VR PID controller. The contactor is the type use in air conditioners. This one is 40 amp with a 240vac coil. The whole system is run on 3-wire 240vac. The PID provides up to 14vdc to trigger the SSR.
Here is a quick shot of the back panel with the elements terminated and hooked up. Last thing to make is a protective cage for the termination area.
Today I powered it up and setup the PID. I did the initial setup with the elements disconnected and with a 75w light buld hooked up to the SSR. The PID manual is not very intuitive so it took some trial and error to figure out the settings. I'm not the sharpest tool in the shed when it comes to things like this but after pushing buttons for a while it starts to make more sense.
After I was comfortable that the PID was operating correctly I hooked up the heating elements. The PID has 4 modes, PID, Manual, On/Off and Ramp/Soak. In PID mode you can auto tune the system to set the PID parameters. Currently the oven is on and set at 200 degs for the first part of the break in. The auto tune took about 10 minutes but once done the temp is holding rock steady. I will keep it at 200 overnight to burn off any excess moisture that may still be in the brick and then do the element break in and install the door gasket tomorrow.
Up and running!
The toggle switch is for the contactor, the green light is on when the contacor is energized. The amber light shows when the SSR is on and the elements are heating. The two red indicators are lighted buzzers for Hi/Low alarms.
- Joined
- Nov 24, 2014
- Messages
- 3,704
Just read this thread.
Nice work jbolt. Looking great.
Wondering if you're going to post a wiring diagram? It would be a help to the electronically challenged, like me.
I'm subscribing so I won't miss the Christening.
Nice work jbolt. Looking great.
Wondering if you're going to post a wiring diagram? It would be a help to the electronically challenged, like me.
I'm subscribing so I won't miss the Christening.
