My line of thinking is.
We use PIDs at work. They have to be gas Calibrated Every 12 months with new bi metal probes. They have usually drifted 50 degrees or more.
How is that any better then using a mechanical thermometer? It can't see any issue even if the thermometer is not accurate. As long as the inaccuracy is consistent. Then that is fine. If it's telling me 710 degrees at 740 degrees ever time, fine.
I keep it at what ever temp by that thermometer that produces good bullets with that alloy. Using the same thermometer every time. Unless I shock it or drop it.
Then I am going to get good bullets.
Just like the rule of using the same tape measure start to finish on a project. Or calibrating all tape measures to a standard rule that stays it the shop.
The only sure way to have accurate measure. Spend the 2 or 3 grand and get a calibrated mercury or gas Rheostat. Like they calibrate PID's with.
The only real reason I can see using a PID would be to take some of the human interaction out of the process. Then yes.
No but when the thermostat lets the temperature vary over 100* between off and on, it is a problem.Is the precise temp as important as having it consistent thru the entire run?
And that is why I use a PID. Call it peace of mindNo but when the thermostat lets the temperature vary over 100* between off and on, it is a problem.
....As long as the inaccuracy is consistent. Then that is fine....
A PID stabilizes the temperature a lot quicker when adding sprues and fresh material to top up the pot than a thermostat...
Hi,I don't think there is anything more important to good casting than mould temp. Turning up the heat or having it not vary 50 degrees pales beside the idea of a cool mould.
Hi,
But...Would that not be related?
If your Lead Temp is more steady and at optimum Temp, won't your Mold?
I would think so?
If you continuously monitor your mold temp as you go through a casting cycle you will see the how fast the temperature changes during the fill, solidification, and after bullet drop out. Lots of heat loss (more than double) if you keep the mold blocks open vs closing them quickly after dropping the bullet....
Hi,Maybe but . . . Probably not if not PID controlled. A consistent Goldie Locks mold temp is the secret to good casting. The Goldie Locks mold temp is easier to maintain with a steady pot temp but the bottom line is . . . Mold temp.
When I'm casting 41 cal 255gr ranchdogs with a 6 cav lee mold, that pot goes down quick, even when dropping the hot sprues off the top of the sprue plate into the pot. When using a mold like that, I often get to 25% or less, before stopping to add a bunch of cold ingots and taking a coffee break.When I was using the Lee 20# bottom pour pot, never let the alloy go down to 25 percent. Halfway, is about all I can manage at one sitting. Need to get up stretch my legs and take a break. <<<SNIP
YMMV