Positioning of PID probe-Toaster Oven

[Hossfly]

I’m going to do that with a boolit, either drill one or pour one around the bead of a k type therm-o-couple. What works best? Pouring or drilling?

[Dragonheart]

I’m going to do that with a boolit, either drill one or pour one around the bead of a k type therm-o-couple. What works best? Pouring or drilling?

Tied drilling first one and it held for a while, but bad choice. Second go round I purchased a five pack of K thermocouples for cheap off Amazon. I cast a couple of them into bullets using a mold cavity. Both of those are working great. I can run two ovens at the same time and just plug a thermocouple into the thermometer.

I have a three of the" TM-902C Digital LCD K Type Thermometer Meter Single +Thermocouple Probe US"
on the way to me now I picked up off ebay for $14.15, so each oven will soon have its own.

[Conditor22]

▲▲▲TM-902C Digital LCD K Type Thermometer Meter Single +Thermocouple Probe US Measurement range: -50°C to 750°C (750°C × 9/5) + 32 = 1382°F ▲▲▲ $3.85 ea shipped chaep thermometer for casting pot if you get a longer thermocouple


100/150/200/500mm K-Type Thermocouple Probe Sensor Temperature Controller 200mm $2.47 500mm $4.28 shipped Temperature Range: -50°C to 1200°C
(1200°C × 9/5) + 32 = 2192°F

[mvintx]

I'd like to chime in with a thought...what about using one of those infrared thermometers to read the temp of the bullet? I have used mine to see how how the coals are in my woodstove. I get a reading of around 650 degrees F when I shoot the beam through the glass door.

[Willbird]

I'd like to chime in with a thought...what about using one of those infrared thermometers to read the temp of the bullet? I have used mine to see how how the coals are in my woodstove. I get a reading of around 650 degrees F when I shoot the beam through the glass door.

The issue with using IR is that different surfaces emit different levels of IR at the same temperature. To see this first hand flux your lead pot really well and try to get an accurate IR temp of the shiny molten lead, then float a penny in there and take a reading from that.

Some object in the oven might work as a good IR target...but maybe not the bullets being PC, could be (I have not played with it yet) that different types and even colors of PC may have a different emissivity profile

Emissivity is defined as the ratio of the energy radiated from a material's surface to that radiated from a a perfect emitter, known as a blackbody, at the same temperature and wavelength and under the same viewing conditions. It is a dimensionless number between 0 (for a perfect reflector) and 1 (for a perfect emitter).

Knowledge of surface emissivity is important both for accurate non-contact temperature measurement and for heat transfer calculations. Radiation thermometers detect the thermal radiation emitted by a surface. They are generally calibrated using blackbody reference sources that have an emissivity as close to 1 as makes no practical difference.

When viewing ‘real’, more reflective surfaces, with a lower emissivity, less radiation will be received by the thermometer than from a blackbody at the same temperature and so the surface will appear colder than it is unless the thermometer reading is adjusted to take into account the material surface emissivity.

Unfortunately, because the emissivity of a material surface depends on many chemical and physical properties, it is often difficult to estimate. It must either be measured or modified in some way, for example by coating the surface with high emissivity black paint, to provide a known emissivity value.

https://www.npl.co.uk/resources/q-a/...vity-important

Dragons method of reading the core temperature of an actual bullet will do far better at making sure the substrate temperature has reached the desired/specified level.

I have no doubt that the emmissivity profile may even change as the PC is raw, when it flows, and perhaps when it cures....then it should stabilize until the baking starts to damage the coating when they have been in too long.

Bill

[Dragonheart]

The only thing I have found the IR thermometers are somewhat useful for is checking the preheating mold temperature while it is setting on a hot plate, but for most of the things in our casting/coating hobby you need accuracy these just do not have.
A Taylor Oven Guide thermometer to monitor you oven's air temp, about $12 off Amazon. A cheap K-type digital thermometer TM-903C with a K- probe, I got 3 off evil bay for $14.15 delivered. It is so simple to cast the probe end into a bullet and place it in the oven wherever you want. Add on a seperate long K-probe about $2.70 ea. and you can check you casting pot temp. Extra probes are cheap in quantities of 5.

[Willbird]

The only thing I have found the IR thermometers are somewhat useful for is checking the preheating mold temperature while it is setting on a hot plate, but for most of the things in our casting/coating hobby you need accuracy these just do not have.
A Taylor Oven Guide thermometer to monitor you oven's air temp, about $12 off Amazon. A cheap K-type digital thermometer TM-903C with a K- probe, I got 3 off evil bay for $14.15 delivered. It is so simple to cast the probe end into a bullet and place it in the oven wherever you want. Add on a seperate long K-probe about $2.70 ea. and you can check you casting pot temp. Extra probes are cheap in quantities of 5.

What does the eBay thermo look like ?? Ok searching and found TM-902C

[Dragonheart]

What does the eBay thermo look like ?? Ok searching and found TM-902C

Sorry can't type it is a TM-902C. They are cheap, but accurate, at least up to the 400 degrees I have checked them against a serviceman's thermometer. With a long probe they also agree with my casting thermometer at 800. The only downside is they read in celsius and not fahrenheit, but a conversion phone app or just memorizing a couple of reading takes care of this.

[Willbird]

Sorry can't type it is a TM-902C. They are cheap, but accurate, at least up to the 400 degrees I have checked them against a serviceman's thermometer. With a long probe they also agree with my casting thermometer at 800. The only downside is they read in celsius and not fahrenheit, but a conversion phone app or just memorizing a couple of reading takes care of this.

I have a solder station that is degrees C only, I just make sticky notes when I decide on a new temperature that I might need to set it to . I could get fancy and put an arduino between the temperature sensor and the solder station so it read out in F , too lazy .

Bill