Quenching Methods

[izafireman]

Yep, a hole is drilled thru the rear of toaster oven with probe tip positioned about an inch above the brick. I'd NEVER put a blade in the oven until I've tested it a few times to be sure it's holding correct temp and not cycling too much. It doesn't take the expensive TC for a tempering oven, just the cheap $5 units seem to work just fine.

I built my PID controller in a box with a 120vac recept that is controlled by PID. The oven is plugged into recept and oven t'stat turned up to max, and timer set to "ON" (doesn't time out) and go from there. None of the work of removing oven controls and rebuilding.

That's interesting to hear you did no rebuilding as my father was saying the same be it a HT kiln or tempering oven, the controls can be away from the unit if in a 'project box' Certainly saves the reworking of the toaster oven.

 

[joe sangster]

Excuse my ignorance but what is a PID ya'll keep talking about ?

 

[izafireman]

Excuse my ignorance but what is a PID ya'll keep talking about ?

I am sure some will correct me here but in simple terms its a switch which when used with a relay can control temperature, which in the case of HT ovens and tempering ovens needs to be accurate. It can make changes to temperature very quickly and accurately and also be programmed to do certain functions. For example if one was fitted to my oven which is not accurrate along with a relay and thermocouple the oven would be accurate , maybe .5 -1 degree of accuracy . The PID ...if ….the right model could be programmed to perform many different functions......an example might be heat the oven to 100C......hold it for 10 mines.....now ramp up the heat too 200c......and hold it for 20 mins then let me know when this is complete via an alarm. Its just a very clever and accurate switch to control an oven or element .

So if you have a toaster oven that is useless, you can modify as in the instructions in the links on this thread and it will be accurate.
What you are doing id removing the $1 controller it came with which is rubbish with a $100 (just an example) switch that 'thinks' for a better word and can control the power / instructions to the heating element at lightening speed accurately....which means stable accurate temperatures that don't fluctuate.

What is a PID Controller?

A PID controller is an instrument used in industrial control applications to regulate temperature, flow, pressure, speed and other process variables.

www.omega.com

 

[KenH]

Simple terms, it monitors the temperature (or pressure, flow, etc) and turns the heater on or off to control temp at setpoint. Best would be a controller than turned heater on a little bit as the setpoint is approached.

PID is a proportional–integral–derivative controller. See the P-I-D? This type of controller is perhaps best explained by this link:
https://www.csimn.com/CSI_pages/PIDforDummies.html

 

[izafireman]

Simple terms, it monitors the temperature (or pressure, flow, etc) and turns the heater on or off to control temp at setpoint. Best would be a controller than turned heater on a little bit as the setpoint is approached.

PID is a proportional–integral–derivative controller. See the P-I-D? This type of controller is perhaps best explained by this link:
https://www.csimn.com/CSI_pages/PIDforDummies.html

My father was telling me he used to fit them on machine in a confectionary factory (Hall's Menthol sweets) as the machines need accurate switches to keep the liquid sweets (candy) at the perfect temperature along with the machines that had heaters for the wrappers......and the was 20 years ago!
PIDs have moved on since then but they still make basic version he used to fit.

 

[Doug Lester]

High speed quenching oils are oils that are specially formulated to quench shallow hardening steels past the nose of the TTT diagram at about 315° C. Steels like the simple 10XX and W series steels have about one second or less to achieve this or you risk ending up with a mixture of martensite and pearlite in the blade or maybe just pearlite altogether.

You may want to look up some knifesmiths on your side of the pond to see where they've been able to obtain high speed quenching oils. Owen Bush at Bushfire School of Knifesmithing and Swordsmithing might be a person to check with.

Doug

 

[izafireman]

High speed quenching oils are oils that are specially formulated to quench shallow hardening steels past the nose of the TTT diagram at about 315° C. Steels like the simple 10XX and W series steels have about one second or less to achieve this or you risk ending up with a mixture of martensite and pearlite in the blade or maybe just pearlite altogether.

You may want to look up some knifesmiths on your side of the pond to see where they've been able to obtain high speed quenching oils. Owen Bush at Bushfire School of Knifesmithing and Swordsmithing might be a person to check with.

Doug

Thanks Doug I will look him up.