Temperature Measuring - My conclusions

[Mike W1]

First I wish I'd had a secretary on hand rather than making notes later in the process a little later. Might have been easier at least.

I only have 4 PID units and a VOM that will read temperatures along with an assortment of TC's. All moulds are DC. Also the Tel-Tru unit of course.

Doubt that a few degrees difference in readings matters much but didn't ever note any using any of the PID's or the VOM measuring using assorted TC's,on a stabilized melt. But the Tel Tru responds much slower and is harder to read.

My pots are both 10 pounders but I doubt 20's would vary the results much if any. Obviously if you add cooler material to the pot the temperature of it all changes and that can take a bit of time depending. But I've measured 3 depths at at a time and they don't vary top to bottom. So I use stacked pots to feed the lower one metal a degree or two hotter and the lower one does not drop.

I drilled my moulds to hold TC's so I know what they work best at. So a little more measuring yielded the optimum temperature to set the PID controlled hot plate to bring a cold mould up or maintain it when taking a break. I believe the guy suggesting 1/2" off the bottom and side of the pot knew what he was doing. Between that spacing and the PID magic is why I don't see temperature change while lowering the level of the melt

The tip of the TC is where the temperature is determined.

Now when the meters read their set values things are good to go just with the flip of the switches. Lots simpler for me.

Can't think of anything else to measure. Guess I'll just have to cast the easier way. And all the PID's were cheaper to build than buy assembled and were fun projects to boot.

[jsizemore]

It's tough to beat the PID/thermocouple setup......until it goes bad. I've only had to replace 1 thermocouple. I've got 4 PID's all built a little different for uses in casting, reloading and coating. Sure makes things easy. I do appliance repair so have lots of build material. Local electronics recycler lets me pick their bins for cases to house the builds.