Who's running a thermometer on their molds?

[Bigslug]

Been running a PID on the pot for a few weeks now, and have to say I like the added control and knowledge it brings to the party. The notion of real time data coming off a probe in the mold is intriguing.

For those rolling with this setup, tell us of your observations: what has it done for you?

[josper]

I don't use a pid, just a thermometer. I also use the digital thermometer that NOE sells to monitor the mold temp. That is key for me.

[bangerjim]

I preheat my molds on an 800 watt plate. That is all the temp control I need on a mold.

banger

[leftiye]

Put a half inch thick piece of aluminum on top of your plate to set your molds on (Put a half gallon can with a side cut out over your plate too). It will flatten out the plate's temperature fluctuations as it cycles. It will also speed heat your molds whenever they are replaced on it (stores heat). I use mine during casting to kick the mold temp to a stable temp for each cast. I have a 1 inch hole in the middle to set hollow point pins down in. I'm coveting one of the pid temp controllers for my pot (which has large, noticeable temp. variations - as per the thermometer) to keep temps in a narrow band.

[Fishman]

I have the NOE temp probe and haven't found it as useful as I hoped. The pid controller and a hot plate have pretty much negated any need I had for it. I think it could be useful for difficult casting situations like .22 caliber.

[Bigslug]

I have the NOE temp probe and haven't found it as useful as I hoped. The pid controller and a hot plate have pretty much negated any need I had for it. I think it could be useful for difficult casting situations like .22 caliber.

Kinda the way I'm thinking too, having just integrated a PID and hotplate myself. We obviously don't NEED to wire our whole operation like a Christmas tree to get good bullets. I think my main curiosity here is to learn what the mold is doing as we pour, wait, drop, and pour again. How much does it heat up during a pour? How fast does it drop that heat? What do molds of identical dimensions do when made out of iron, aluminum, or brass?

Seems like somebody would have done some hard science on this, as it would be useful stuff to know, rather than speculate on. Maybe I've got a mission here. . .

[theperfessor]

Bigslug -

I built a dual PID controller (there's a sticky here about it) to control pot temp and monitor mold temp. It is interesting to watch the temperature swing in the mold. You can draw your own conclusions about what you see as the mold cycles.

The biggest benefit to me is the ability to reduce the pot temp to a minimum and still get consistently good results by having the mold be the same temp for every pour.

Have fun with yours!

To all -

No, you don't need a PID controller or even a thermometer to cast good bullets. You don't need a scope on a rifle or a laser grip on a pistol either. But once I started using a scope, a laser, and a PID I won't go without any of these for the majority of my uses. The tools you choose to use are your business. But I like having these things, the enjoyment of using them far outweighs their relatively modest cost.

[felix]

BigSlug, take a good look at TheProfessor's last paragraph. Memorize it. Doesn't your modern car run much better than those pre-80's/90's? The only real difference between them is in the measurements and feedback control functions. ... felix

[bhn22]

As much as I sometimes appreciate modern conveniences, I monitor mold temp in a simple manner. I touch the sprue plate screw with a piece of beeswax when I think it's ready, just a light touch. If the wax melts instantly, I'm ready to begin, and have already lubricated the sprue pivot. If not, I check back in a minute or so. This is so totally unscientific and unvalidated that I hesitate to mention it. If the wax smokes, I've gone too far and need to let it rest for a few seconds.

[Mike W1]

Bigslug -

I built a dual PID controller (there's a sticky here about it) to control pot temp and monitor mold temp. It is interesting to watch the temperature swing in the mold. You can draw your own conclusions about what you see as the mold cycles.

The biggest benefit to me is the ability to reduce the pot temp to a minimum and still get consistently good results by having the mold be the same temp for every pour.

Have fun with yours!

To all -

No, you don't need a PID controller or even a thermometer to cast good bullets. You don't need a scope on a rifle or a laser grip on a pistol either. But once I started using a scope, a laser, and a PID I won't go without any of these for the majority of my uses. The tools you choose to use are your business. But I like having these things, the enjoyment of using them far outweighs their relatively modest cost.

Being your the only one that replied with an answer to the question it would be interesting to hear how much the temperatures vary on a mould when you cast. I've read all your stickies and don't recall that being brought up.

[kbstenberg]

If any of yall don't like there NOE mold temperature monitor I could use it. PM me and we could make a deal. Kevin

[theperfessor]

For some testing I was doing I was using molds made from both aluminum and nodular iron. The five cavity molds were approximately 20% longer than a Lyman four cavity mold and had about the same cross sectional dimensions. I was trying various alloys at 675F to 725F and using a mold temp of 400F at the start of the pour. The molds typically heated up 20F to 35F. I was trying for a four-five second sprue freeze and good fillout and a fifteen to twenty second cycle time. Letting the bullets stay in the mold for several seconds after the sprue freezes maximizes the heat gain/temp increase in the mold. (I've often heard that you should heat up a mold by casting as fast as possible; this is not necessarily true - there is a slightly slower pace that will heat a mold up faster - heat is still being transferred to the mold after the sprue freezes.)

It is also interesting to see how fast a mold cools once it is opened and especially when the bullets are out of the cavities. I believe many beginners get wrinkly bullets because they don't get a mold up to temp because they look at their output while they hold the mold open too long, or they lose heat while they try to get the bullets to release from a balky mold. A mold that releases bullets easily can be run at a faster pace and slightly lower temps.

Since I obviously haven't tested every mold out there I can only report what I have observed, thus my comment to observe first hand and draw your own conclusions.

[fatelvis]

I just started using the NOE probe and love it! I was in the habit of running hot alloys and shooting frosted boolits, and the probe helped me bring down the alloy temp and maintain the mould temp in the proper temp range. (Admittedly I wasn't pre-heating my moulds on a hotplate before either). Now my boolits are fully filled out, but nice and shiny, and my alloy has noticeably less dross on it when casting.

[dromia]

I have a PID on my Promelts and although it is informative and helpful in letting you know when the pot is up to temperature if I had to I could live without it.

I also have the mould probe and thermometer and have most of my moulds drilled and tapped for the probe, where I can I order them that way, For the vast majority of my moulds the probe and thermometer don't make a difference, just get them hot and away you go the cooling of the sprue puddle is indication enough. However there are a few moulds that the probe/thermometer is essential to me for and they are ones that for some reason temperature finicky, mainly like to be run cool. I have one mould in particular from Accurate that casts a design that I shoot 200-500 boolits a week of. It is five cavity and to get the best fill out it needs to be run very cool relatively. Since fitted for the probe it just throws fine boolits with ease, before when I was guessing about its temperature I would get bad patches of boolits as the temperature went past the sweet spot.

So for me the mould thermometer is the biggest add on to help with my casting of all these extras.

[leftiye]

I just started using the NOE probe and love it! I was in the habit of running hot alloys and shooting frosted boolits, and the probe helped me bring down the alloy temp and maintain the mould temp in the proper temp range. (Admittedly I wasn't pre-heating my moulds on a hotplate before either). Now my boolits are fully filled out, but nice and shiny, and my alloy has noticeably less dross on it when casting.

How's your weight consistency/range? Beware them shiny boolits, they don't fit as tight in yer mold (a tech bigger, maybe heavier, and more variance). Borderline frosting is your friend.

[popper]

I use my PID on the pot & try for just this side of frosting on the boolits. Thermometer doesn't tell me that. Yes I have measured mould temp, don't anymore.

[fatelvis]

How's your weight consistency/range? Beware them shiny boolits, they don't fit as tight in yer mold (a tech bigger, maybe heavier, and more variance). Borderline frosting is your friend.

Honestly, I just weigh the first cast to see what a sized, lubed bullet weighs total, so I couldn't answer that. And for bore rider designs, I still feel a nice slip fit when sliding the bullet nose into the muzzle of my rifles. Unscientific, but tends to be a good indicator of proper fit for me.
I always had good luck shooting frosted boolits, but I got sick of seeing the pretty, shiny boolit pics all the time and had to make some myself!
By the way, what is a "PID"? Thanks-

[John Boy]

Who's running a thermometer on their molds?
The notion of real time data coming off a probe in the mold is intriguing.

IMO - Totally a waste of time!
Bring the pot temperature up so the sprue puddle frosts in 5 seconds (<300gr) & 8-10 seconds (>300gr). That's all one needs to know for excellent bullets

[Garyb]

I just use the Lee 20 lb pot. It gives me all the control I seem to need. I do check the lead with a thermometer just to verify the temp before I start casting. The pot does the rest for me. I preheat the mold just by moving it through a propane torch. Probably should get a hot plate for the molds though.

Fatelvis - check PID proportional-integral-derivative controller here

[ipijohn]

I'm using a PID, don't own a thermometer that goes that high.