my guess is that a PID is a more accurate way to control temperature in the pot. and, i belive that some also have something in the mold to show temerature. so, here it goes. i cast with a ladle. my bullets are 6.5, 7mm, 30 and 303 calibers. they weight +or- 2 tenths of 1 grain mostly 1 tenth of a grain. i do not have a PID. is my bullet weight accuracy due to ladle casting??
pid question
- Thread starter porthos
- Start date
In my case, a PID unit was convenient and cheap (free). I was in the process heating business at the time and used a thrown-away controller, on which one of the outputs was fried and the unit was replaced under warranty. It was that or a $50 thermometer. I got by many years without a thermometer too, but the CONVENIENCE of hitting the target temp and maintaining it EASILY make things more time-efficient. I personally don't think anyone using the technology is going to make better bullets, so much as making better bullets more efficiently. Having technology is one thing, knowing how to use it is another - meaning that if you can cast good bullets without technology, you'll just cast good bullets more efficiently with technology. I make a living off of technology so I am not just a Luddite disparaging something I don't understand.
Whether a PID is more accurate at controlling the pot temp, or whether it matters so much that one needs to see decimal places in that metric is not something I'd venture a guess at, but it IS convenient to glance up and see where I am temp-wise and hold off another minute or start casting. I can also read the PID display from across the shop, which makes it easy to do other stuff as the pot comes up.
I'll not touch the ladle v. bottom-pour question with a stick as I like the people here and I'm sure I'd upset someone with my opinion on that, even as I have done both extensively.
Just saw @Brad 's reply pop up and I think he's saying what I'm saying, but much more efficiently.
Whether a PID is more accurate at controlling the pot temp, or whether it matters so much that one needs to see decimal places in that metric is not something I'd venture a guess at, but it IS convenient to glance up and see where I am temp-wise and hold off another minute or start casting. I can also read the PID display from across the shop, which makes it easy to do other stuff as the pot comes up.
I'll not touch the ladle v. bottom-pour question with a stick as I like the people here and I'm sure I'd upset someone with my opinion on that, even as I have done both extensively.
Just saw @Brad 's reply pop up and I think he's saying what I'm saying, but much more efficiently.
JonB
Halcyon member
porthos,
It sounds like you are doing fine without a PID...add to that, I suspect a PID wouldn't help you tighten, your already tight casting results.
Is it correct for me to assume (reading between the lines here), that you are wondering why some people say that a PID was a gamechanger in their casting results?
I am one of those people, and here is why.
I use a Lee 4-20 bottom pour lead pot. The temp control on the Lee, leaves a lot to be desired. Temp swing can be ±20ºf under normal operation with the pot full, which isn't that big of a deal. The Big Deal happens, as the alloy level decreases, the temp control design makes the alloy temperature increase...by about 50º once you get below half empty ...and even 80º when about 3/4 empty.
Now, we all know that mold temp is much more important than alloy temp, when casting consistent weight bullets. But a 50º to 80º jump in temperature has to be compensated for in casting rhythm or dialing back the Lee control, to maintain bullet consistency. With the PID keeping alloy temp within a few degrees, at any pot level, it simplifies the casting session for person who uses the bottom pour technique. I've never really given ladle casting much of a try, I suspect there is something about it, that is less influenced by pot alloy temp...I mean folks use to cast bullets using a pot in a campfire.
It sounds like you are doing fine without a PID...add to that, I suspect a PID wouldn't help you tighten, your already tight casting results.
Is it correct for me to assume (reading between the lines here), that you are wondering why some people say that a PID was a gamechanger in their casting results?
I am one of those people, and here is why.
I use a Lee 4-20 bottom pour lead pot. The temp control on the Lee, leaves a lot to be desired. Temp swing can be ±20ºf under normal operation with the pot full, which isn't that big of a deal. The Big Deal happens, as the alloy level decreases, the temp control design makes the alloy temperature increase...by about 50º once you get below half empty ...and even 80º when about 3/4 empty.
Now, we all know that mold temp is much more important than alloy temp, when casting consistent weight bullets. But a 50º to 80º jump in temperature has to be compensated for in casting rhythm or dialing back the Lee control, to maintain bullet consistency. With the PID keeping alloy temp within a few degrees, at any pot level, it simplifies the casting session for person who uses the bottom pour technique. I've never really given ladle casting much of a try, I suspect there is something about it, that is less influenced by pot alloy temp...I mean folks use to cast bullets using a pot in a campfire.
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Good points, @JonB , and I can back up those assertions based on my observations as well. The temp control on the Lee pots (and probably others) is pretty crude. A PID's dislay can make that very apparent. Using the PID output to control the pot within a much narrower band is helpful.
I regulate my MOULD TEMP, while casting by rythm and POT TEMP. It's easier to to keep an eye on a LED display as you cast than a thermometer. Not having a PID controlling mould temp, or the digital display that goes with that type of control leaves one to watching bulets as they come out of the mould to determine if the MOULD TEMP is OK. I stick a cheap TC into a cavity of a mould on a hot plate and don't start casting until it reaches the "right" temp. Thereafter, it's up to me to watch the bullets to make sure my mould temp stays right. I'd hate to have to handle a mould with a TC wire hanging off of it.
If you don't toss sprues back in as you go, it's easier to maintain the pot temp within a smaller band. If you DO throw sprues back in as you go, it's easier to keep an eye on the digital display and STOP tossing sprues back in before you drag the pot temp down too far. I've done it both ways and just keep an eye on the PID display. The PID will not keep up correcting temps when you pile a bunch of cold sprues into the pot.
Bear in mind that I do not assert that I am doing this ultra-scientifically either, nor are exact temps critical to me. When I say my aluminum moulds start casting well at 386F, I don't mean that 386F is THE temp for all purposes - it's relative.
@JonB may be approaching this more scientifically than I am, as I started using one, as I said, as a convenience, since I had the stuff to build one. The controller does control the pot MUCH more efficiently than the original controls, but it doesn't matter if the operator is making it difficult for the controller to keep up.
I regulate my MOULD TEMP, while casting by rythm and POT TEMP. It's easier to to keep an eye on a LED display as you cast than a thermometer. Not having a PID controlling mould temp, or the digital display that goes with that type of control leaves one to watching bulets as they come out of the mould to determine if the MOULD TEMP is OK. I stick a cheap TC into a cavity of a mould on a hot plate and don't start casting until it reaches the "right" temp. Thereafter, it's up to me to watch the bullets to make sure my mould temp stays right. I'd hate to have to handle a mould with a TC wire hanging off of it.
If you don't toss sprues back in as you go, it's easier to maintain the pot temp within a smaller band. If you DO throw sprues back in as you go, it's easier to keep an eye on the digital display and STOP tossing sprues back in before you drag the pot temp down too far. I've done it both ways and just keep an eye on the PID display. The PID will not keep up correcting temps when you pile a bunch of cold sprues into the pot.
Bear in mind that I do not assert that I am doing this ultra-scientifically either, nor are exact temps critical to me. When I say my aluminum moulds start casting well at 386F, I don't mean that 386F is THE temp for all purposes - it's relative.
@JonB may be approaching this more scientifically than I am, as I started using one, as I said, as a convenience, since I had the stuff to build one. The controller does control the pot MUCH more efficiently than the original controls, but it doesn't matter if the operator is making it difficult for the controller to keep up.
CWLONGSHOT
Well-Known Member
I "thought" I was doing great with out a PID... Then I got one...and learned...
Last year I was happy warming my molds on the top of my pot. Like dad did. Then I bought a hot plate... AND LEARNED!
REQUIRED? NO, but ITS A NIGHT AND DAY improvement.
CW
Last year I was happy warming my molds on the top of my pot. Like dad did. Then I bought a hot plate... AND LEARNED!
REQUIRED? NO, but ITS A NIGHT AND DAY improvement.
CW
I was perfectly able to do just that without the conveniences mentioned, and have a relaxing day doing it. As time went by, time became more precious - harder to co me by. Whereas I once dedicated a DAY to casting now and then, anymore I can only dedicate a couple hours here and there where I can find them.
My typical casting session is while doing laundry, on really cold, really wet or cold AND wet days, when I can't attend to much else. Using the PID on the pot and a cheap meter with a TC in a mould on the hot-plate, I can stop in the middle of a session, fold/hang a dryer-full, shuffle the just-washed laundry into the dryer and start a new load in the washer - return to the pot and cast the next moulds-full without missing a beat or creating culls as I get everything going again.
I think if I hadn't adopted these new things we could do without, I'd probably get about a tenth of the casting done that I do. I am also a care-giver and am basically on-call 24/7 and have to be able to drop whatever I'm doing instantly to attend to other responsibilities. Not complaining - just putting my use of the conveniences discussed into context. The only time I really place my time "off-limits" is if I am doing a glue-up/assembly on a furniture project, and I make sure everything is in order otherwise and announce that "I'm going to glue - is there ANYTHING i need to do first?"
If I have a "more than minor" interruption while casting, I can simply turn off and unplug the pot and hot-plate and walk away. It will be set up and ready to go once I am able t o get back to it. Obviously not ideal for everyone, but it does allow me to keep up with casting. My (new) PC setup works the same way. I've installed plugs on separate TCs for the pot or the oven and can switch between the two. There is a mechanical timer on the PC (pizza) oven which won't allow it to run more than 15 minutes. If I get pulled away, it will time out and shut down. I need to set it up with a ramp-soak controller, which would allow me to turn on a cold oven, full of powdery bullets, and it will ramp up to temp and then time itself and hut down.
That may be more technical than most want to get and it may even spoil some of the fun, but while I am not a welder, don't have a mill or know squat about a metal lathe, but I can do controls easily enough to keep me in cast bullets - actually, me and two others. I suppose that if I wanted another "project" that I could scrounge a control enclosure somewhere, and set it up to make it all a lot more convenient. As it is, it's a pieced together setup, but it works. I wold like the safety aspect of shutting everything down after XX minutes if I walk away though.Shoot, my whole bench needs a rework anyway.
KeithB
Resident Half Fast Machinist
I’ve run lathes and mills without Digital Readouts (DROs) and did good work, but given the choice I’ll always choose to use one because I can do better work faster. Same with using PIDs for casting. I built a dual PID to control pot and hot plate/mold temperature and it works fine.
Use whatever you’re comfortable and happy with.
Use whatever you’re comfortable and happy with.
Bret4207
At the casting bench in the sky. RIP Bret.
Jeff, sounds like you have your hands full! There are many people here who can relate. Maybe a pid would help. I've never used one. If you have the ability and cash flow, go for it! I was just saying it sounds like you're system is turning out great results now!
358156 hp
At large, whereabouts unknown.
Keith, did you ever find the Lyman 450 blueprint article again? That should be required viewing for everyone who casts. It's an inside look at how our reloading equipment is really built, and what we can do to make them truly capable of fulfilling their performance capabilities.
My overly verbose post was meant to back up exactly what you said. I hope I didn't lose that in the volume I posted.