Question about Lee 4-20

[MikeS]

Hi All.

I've seen several people that say they put their Lee 4-20 pot on #8, and then cast with it set at that setting. With my 4-20 if I cast at anything higher than 3.5 or so the melt temp starts climbing real fast over 800 degrees! When using a 4 or 6 cavity mould, I set it at 3.5, and return my sprues to the pot as I cut them, and that seems to keep the pot temp right around 675 degrees or so, which seems to work fine for me with most of my moulds. If I leave the pot alone for any length of time at that setting (not casting, and not returning sprues), the temp starts to climb fairly quickly (like it I take a break, and put the mould back on the hotplate)

So my question is: with these folks that cast with the temp dial set at #8, how hot is their lead in the pot? Wouldn't it be way too hot?

[357shooter]

Some of us get good results casting hot, at least I do. So my preferred temp is 850-900, with an aluminum mould at 400-420 degrees.

That's with moulds for 357/38 special, 158 to 200 grain, and with very soft alloy. That may be the most important point. When possible I cast BHN 8. For most of a casting session the Lee pot is set full hot (110V). I get that specific because it may matter to someone. I haven't cast 300 grain bullets, or 70 grain bullets and don't know at what temp they cast best.

So what's too hot for you isn't too hot for me.

That being said, I'm in the minority. But for some reason I get great consistent bullets casting hot.

Some time back I did a tests to see if anything bad happened to a hot alloy. Such as loosing tin or antimony. The result was and is, nope. No matter what I tried I couldn't cook out enough of anything measurable.

There's a chance not everyone will agree. ;););)

[jmsj]

MikeS,
I have two of the Lee 4-20 bottom pour pots and at the same number on the dial neither will be the same tempature. But neither of them would reach 800*+ on a setting of 3.5.
I cover the melt w/ kitty litter and this has helped keep the heat in and has lowered the settings for the target tempatures. With a 1/2" of kitty a setting 4 reaches around 600*-650*
I think if yours is going over 850* (with or with out the melt being covered) on a setting of 3.5, you may have a bad rheostat on the tempature control.
I would think that if you contact Lee they should be able to help you out.
Good luck, jmsj

[zomby woof]

mine is set under 2 for 625.

[Ole]

Mine @ a 5-6 runs around 720-750 degrees when tossing sprues back into the pot, casting at a quick pace (20-30 seconds or so per mold fill and dump).

[mooman76]

I have no Idea what temp mine is at (no thermometer) but I cast pretty fast and I have to have mine at at least 6, usually 6 1/2 to 7 to get good fill out.

[R.M.]

For mine, the number pretty well corresponds to the temp, so 7 would be 700.

[williamwaco]

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For mine, the number pretty well corresponds to the temp, so 7 would be 700.


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Interesting.

These readings are all over the place but mine agrees with yours.

Setting 6 = 620/640
Setting 7 = 700/720

I have not checked it on any other settings.


The real question is, do the pots vary that much? Or is it the thermometers? Or both?

[Boolseye]

It varies with mine, seems to depend partly on the amount of alloy in the pot. I crank it to get it melted or after I toss the sprues in, but I let it idle usually around 4 or 4.5.
That holds it around 750-800º, which is where I like it. If I leave it at 5-6, the alloy will go past 800º.

[MikeS]

Ok, so it seems that each pot is different, and the numbers correspond to nothing. I usually crank it all the way up, til the lead is melted, then go down to 3.5 or so to do the actual casting. Tonight I was using my hot plate to mix some boolit lube, and forgot to unplug the 4-20 (I have the 4-20, and hot plate on a switched outlet strip), and with it on a setting of 3.5 it seemed to melt the lead in the pot about as fast as it would when I crank it up all the way, so perhaps I don't need to crank it up, just leave it set where I want to use it.

I normally set the hot plate on full HI to warm up my boolit moulds, and by the time the lead is melted to the correct casting temp (I like to cast from 675 to 700) the mould is preheated enough that I can cut the sprues by hand, and don't normally get many if any culls. Yesterday I was casting with a Lee 6 cavity mould (Lee 6 cavity moulds are quickly becoming my second favorite moulds to cast with behind the custom maker moulds of Mihec), and managed to cast 200 boolits with a total of only one cull!

How can I tell if the temp control on my pot is in fact broken as jmsj suggested, or if my pot just likes being set lower than some others? Is it normal for the temp to start rising during a break from casting? (considering that I'm putting the sprues back in the pot directly from the mould, so that could be a cooling influence on the pot)

[geargnasher]

The Lee pot thermostats are on or off. It will heat at the same rate whether the dial is on one or ten, up to the setpoint.

Mine (before I fixed it with a PID controller) was like Ole's and some others, full pot temp was around 700 on 7, but as it went toward halfway I had to turn it down to 5.5 or 6 to keep it from going over 700, and between 1/4 and half full the setting had to be turned down to as low as 4. Keep in mind the ambient air temperature and type of alloy affect settings greatly, plus I'm sure there are great tolerance variations to the bi-metal thermostat, which resides in the control housing, not in the shroud around the pot.

Bottom line is use a thermometer and adjust YOUR particular pot setting to your habits throughout a session as necessary, like if you add sprues back while casting, cast with six-cavity moulds a lot, or what ever you do to affect the metal temperature while you cast.

I don't think your control is broken at all, I just think it cycles faster than some, and adding sprues sucks up a lot of btu's that won't be a factor if you leave the pot sit. Before the PID, I noticed that my pot would stay fairly consistent in temp while unattended, but eventually, over the course of an hour or two, it would heat soak the housing and tend to cycle a bit differently. What do you want for fifty bucks? :) Add a $30 thermometer and spend the $300 you saved on the whole setup on other stuff, like good moulds or primers!

Gear

[fredj338]

I have no Idea what temp mine is at (no thermometer) but I cast pretty fast and I have to have mine at at least 6, usually 6 1/2 to 7 to get good fill out.

I run mine there too. With a full pot, the temp is around 700deg. Of course, as the pot empties, the temp will go up & I will just add ingots to keep it close to the 700deg mark.

[MikeS]

It's strange, when I first started casting, I didn't have a thermometer, and didn't miss it. Then I got an electronic thermometer, and used it all the time, til it stopped working. I sent it back to the manufacturer, and waited for them to quote a repair. While it was gone I really missed having it! Then they let me know they couldn't repair it, so I got a TruTel thermometer (I think that's the name, it's outside, and I'm inside), and it works great, and will probably be working longer than a digital one would.

[kelbro]

How certain are you of your thermometer reading?

[geargnasher]

I use two Tel-true thermometers and a PID controller with thermocouple for occasional comparisons. All three agree within 12 degrees at the melt point of pure lead.

Gear

[JIMinPHX]

For me, I need to strike a balance between how fast I throw sprues back in & how high I set the dial. Also, alloy matters. A setting of 8ish is usually good for pure lead if I move fast. A setting of 6ish is usually good if I am up to temperature & working with WW alloy.

[MikeS]

I guess I should have mentioned that I'm casting with Lyman #2 (or something close to it) when I use the Lee 4-20. When I cast pure lead I use a ladle with a Lyman 10# pot.

[kelbro]

How certain are you of your thermometer reading?

Sorry, this question was directed at the OP.

[44man]

Gear, can you post a schematic of your PID? All the ones I made eventually burned up even with a huge heat sink and parts are far too expensive to repair them.
I need one for my OLD Lyman with a shot thermostat.

[kbstenberg]

44Man just a thought. Did you start your cold pot while it was attached to the PID? That could be why you overheated your electrical comp. In the original thread on building a PID it was stated to start the cold pot plugged into an outlet. Then when the melt is close to a casting temp. switch your electrical source so it goes through the PID.
Just a thought. Sorry if I stepped on any toes.
Kevin

[Colorado4wheel]

My two pots will both cycle when first plugged in with cold lead. So to me they don't even have a temp sensor it's more of a dial that tells the pot how fast or slow to cycle the heater. I have to turn it up to MAX just to get the lead to melt in about 20 mins. Anything below that and it can take forever just to melt the lead. After it's melted and up to my desired temp I have figured out that about 4 on the dial is about 800f. About 3.5 is about 750f. If you make big changes on the dial you get WILD swings in lead temp. I try never to move it more then .25 change to avoid huge swings. I use small drops of sprue to cool it off quickly if it does rise to high. I have a Lyman temp gauge.

[JIMinPHX]

Gear, can you post a schematic of your PID? All the ones I made eventually burned up even with a huge heat sink and parts are far too expensive to repair them.
I need one for my OLD Lyman with a shot thermostat.

In general, a PID controller will use a SSR (solid state relay) as an interface with the power that is being controlled. The SSR is usually what gets burned out. An ohmic load, like a heating element or an incandescent light bulb, will draw about ten times the standard current when they are starting up from cold. A solid state device is sensitive to short duration current spikes. When sizing an SSR, err on the size brutality & get one that is bigger than you think you need. Also, there are different types of SSRs. If you get a "zero crossing switch over" type, then it will handle AC loads better. The zero crossing SSRs don't work on DC loads.

[ColColt]

Mine can be put on 3.5-4 once the alloy has reached liquidus for about 650-675 degrees if using 50/50 lead-Linotype but requires more heat for ww's having to bump it up to about 6 to give that same temp.

[44man]

44Man just a thought. Did you start your cold pot while it was attached to the PID? That could be why you overheated your electrical comp. In the original thread on building a PID it was stated to start the cold pot plugged into an outlet. Then when the melt is close to a casting temp. switch your electrical source so it goes through the PID.
Just a thought. Sorry if I stepped on any toes.
Kevin
No, lead was melted first. I found about 85 volts AC was just right.
The largest dimmer I could find was 1000 watts. The price has gone out of sight and is more then a new Lee pot.

[44man]

In general, a PID controller will use a SSR (solid state relay) as an interface with the power that is being controlled. The SSR is usually what gets burned out. An ohmic load, like a heating element or an incandescent light bulb, will draw about ten times the standard current when they are starting up from cold. A solid state device is sensitive to short duration current spikes. When sizing an SSR, err on the size brutality & get one that is bigger than you think you need. Also, there are different types of SSRs. If you get a "zero crossing switch over" type, then it will handle AC loads better. The zero crossing SSRs don't work on DC loads.
I built a solid state motor control for a few of my die grinders but I would not put it on my lead pot.
Electronics has advanced since I worked with the stuff so I still need a schematic to build, along with part numbers for components. I can't engineer things. It has been over 30 years since I repaired and I have forgotten too much. :mrgreen:

[cajun shooter]

For you who use the Lee pot and try to regulate the temperature with what another caster posted, you are chasing your tail. The Lee is not equipped with a thermometer but a rheostat. It is not a dependable type of instrument as it uses the amount of power to try and keep the settings. A true thermostat uses a real thermometer that is built in. The RCBS PRO has the probe at the base of the pot just above the spout. One pot may work on 7 while another works on 5. Another problem with them is that they are not calibrated well enough to keep your alloy at a steady temperature.
You have to use a real thermometer and even better is to have another pot that contains alloy at the correct setting so that when you add alloy you are not back to chasing your tail.

[44man]

I thought Lee uses a remote thermostat that is kept away from full pot heat. The knob is a rheostat but there is still a thermostat. I don't know how it reads temps unless there is a sending unit.
A rheostat will not cycle.

[Mal Paso]

I thought Lee uses a remote thermostat that is kept away from full pot heat. The knob is a rheostat but there is still a thermostat. I don't know how it reads temps unless there is a sending unit.
A rheostat will not cycle.

First, Thanks for your help in the past!

Lee does Not have a Thermostat. It is more like an Infinite Control on an electric range. While the heater is on a Bimetal Switch inside the Lee Control heats to a point where it breaks contact turning off the heating element and heat in the switch. The switch cools, makes contact again, and starts the heat cycle. It behaves a little like a thermostat in that heat from the pot affects the the control but that's all.

A PID Controler is different from a dimmer or the Lee Control. http://castboolits.gunloads.com/showthread.php?t=115724 I just built one and Would Not Go Back. All that attention that went to temperature control is now spent on better boolits. I'm running the pot Much Cooler because I don't need to allow for a temperature Range, the temp is exact.

[Mauser Rat]

Is it true that the pot should not be plugged in to a PID during initial temperature ramp up though? With the new solid state relays?

I have no idea and am just thinking of protecting my new PID. And I second that about going back. Now that I have the PID I can think about a lot of things other than temperature of the lead and the lead will remain within 1 or 2 degrees of where I set it no matter how full the pot is.

Thanks all and excuse the interuption!

[Mauser Rat]

P.S. There are instructions on how to construct a PID over in the "Casting Equipment" forum if any are interested. They are easy enough to follow that even I was able to build a PID and I am electronically challenged to say the least!

[Sonnypie]

I don't have a thermometer. I'd rather kick the cow pies to see how old they are.
Ignorance is bliss! [smilie=1:

I started high and have come back to 5 1/2 on mine. (Over many casting sessons, and around 2000 of the same boolits, same mold.)
I judge by the "set time" of the sprue, and the sheen of the boolit, and the quality of the cast.
Being familiar with electrical controls, I can judge what's going on by listening to the control cycle on and off and for how long.
I seem to do OK by flying by the seat of my pants with a lot of things.

My only "mishap" was leaving the furnace for about 1/2 hour at around 8 setting and this crust of dirt looking junk formed. Probably from the rosin core flux from some electronics solder I had added.

Otherwise, all's been well for me.
I don't over think things, and have learned to not reinvent the wheel.
I don't really see where I need a thermometer for my lead, yet.
If it's scary, it's too hot.
If it's aggravating, it's too cold.
If it's in range, adjust your speed of production.
YMMV

Oh, I also reintroduce my sprue back in the pot as I roll along, too. Maybe that helps keep the pot in a good range?
Beats me. But I'm happy with my boolits so far. :coffeecom

[44man]

First, Thanks for your help in the past!

Lee does Not have a Thermostat. It is more like an Infinite Control on an electric range. While the heater is on a Bimetal Switch inside the Lee Control heats to a point where it breaks contact turning off the heating element and heat in the switch. The switch cools, makes contact again, and starts the heat cycle. It behaves a little like a thermostat in that heat from the pot affects the the control but that's all.

A PID Controler is different from a dimmer or the Lee Control. http://castboolits.gunloads.com/showthread.php?t=115724 I just built one and Would Not Go Back. All that attention that went to temperature control is now spent on better boolits. I'm running the pot Much Cooler because I don't need to allow for a temperature Range, the temp is exact.
The bimetal switch IS a thermostat, they all work the same.

[Mal Paso]

The bimetal switch IS a thermostat, they all work the same.

Sort of, however most of the heat that cycles the switch on and off comes from a heating element In The Switch. The heat from the pot is a secondary influence. It works ok but I have PID Control Probes installed on both my Lee 4-20s. I should have done it sooner.