Casting Thermometer - got a serious education

[Tazman1602]

Oh boy. I've been a bullet caster for 25 years now. Since finding this forum though, my casting has increased exponentially.......as has my stock of bullet molds.

I've always been a ladle caster but last year for Christmas my wife got me a 20# Lee drip-o-matic bottom pour. Wanted that just so I could have 20 pounds of lead hot and ready instead of my little Lee and Lyman mini-mag type melters.

It's got a thermostat on it right? Well, kind of. I disliked it pretty much until I got the hang of using a bottom pour pot but still had some issues and on my big bore stuff (.35 and up defined by me...) I always ladle poured.

You know the story. Lead too hot. Lead too cold. Play with the thermostat until I thought I had it about right which was setting number 8 on the pot thermostat. I would turn it down to 7 when it got really too hot and thought I had it right on. Molds still got hot very fast so there was some frustration involved.

Reading about casting temps on this forum, the use of thermometers, and the fact I can't afford $350 for the RCBS melter I would like, and not wanting to spend $50 on a thermometer I just trudged along.............until a week or so ago.

Then I found a place that I believe makes the Lyman and RCBS 200-1000 degree F thermometers but their price is $19 -- that I will gamble on.

It came in yesterday and I fired up the pot after making a bracket for it -- if anyone has pics of how they mount their thermometer I'd certainly appreciate it BTW.

Turned the pot on to get the melt going, set it to #8 to get it up to temp and let it melt. Then I put the thermometer in the mix.

I just about went poopy. At what I thought was the proper setting my lead temp was almost 850 degrees...........oh boy, here we go. Kept turning pot back until I reached just shy of 750 degrees and started casting. Many problems just went away...........and the correct setting for this temp with a full pot is setting number 5...FIVE, not 8!!!! Much nicer bullets, drops better, more consistent pours. As I understand it from reading posts, ideal temp is somewhere between 700-750 degrees with some posts saying to cast at even lower temps.

Maybe this should be a sticky, I've researched the stickys, done searches -- I KNOW somewhere on this forum is a post about "what temperature should I have my lead at before I cast?" but have been unable to find it.

I realize it depends on what alloy you are using, but what do most of you with thermometers use as your ideal casting temp for WW lead and Lyman #2 mix? Steel molds? Aluminum molds? Brass Molds?

I've seen Fryxell's chart on the melting points of different alloys, but that still doesn't tell me what temp to actually pour at.

What do you say? Tell me your temps! Man I learn something new every day here.............

Art

PS - Here's the link to the people who will get you a casting thermometer for $19 + $9 UPS:

http://www.teltru.com/p-272-big-gree...degrees-f.aspx

They are EXCELLENT people to deal with also...................

[onesonek]

Yeah, those dail numbers are really more a reference than anything. I'm running mine about midway between 4 and 5, at 660 and 690 with my molds ( brass and Alum.) and the mathmatical 93-5-2 alloy I'm using at present.

[old turtle]

After many years I finely got off my wallet (I know I am cheap) and bought a RCBS thermometer. I discovered the same thing as you gentleman. I have come out of the wilderness. At least a little ways.

[jsizemore]

And the other fun part is when the lead level in the pot gets to 1/2 or less the, temp starts fluctuating wildly. You really have to keep an eye on the thermometer or fill the pot up. Until you add a thermocouple and PID controller.

[sargenv]

I've been keeping my pot at between 700 and 725.. I then put two corn muffin ingots stacked on top of the pot to heat up before putting into the melt. When I figure I've poured about a pound of bullets (about 50-60 9mm bullets) I drop in a pre-heated ingot, and watch the temp drop to about 675 (still within casting temp) and then gradually work it's way back up to 700-725.. If I were pouring bigger bullets, I would likely set the temp to 725-750 so that the increase in dropping warm (but not as warm as I want) ingots in would not hinder production.. So far the pot has stayed topped up while I cast.. Currently my production run is a 6 cavity - 9mm 125-2r that I use as cores for my 9mm swaged into 40 bullets.. I usually make from 600-1200 a sitting. My production is in the range of 21 per minute so it really doesn't take much time to crank em out, and I am dropping ingots in about every 3-5 minutes.

[Springfield]

I use a biger Magma pot most of the time that I run around 650-675. As it is 1500 watts adding more lead isn't a problem like with my smaller RCBS and LEE pots. But I run a thermometer on all of them, otherwise I have the same problems as you.

[mold maker]

I premelt in a cheap ladle pot and dip molten into the BP pot. No time needed waiting for the temp to come back up or stabilize. I just add 2 ingots to replace the 2lbs I transferred and cast on.
The only problem was that when casting for a 45-70, the little refill pot couldn't keep up with the 405 gr 6 cav, rate of use. Of course my old bones couldn't either, so a break was welcome.
I'm thinking of mounting a LEE BP pot on a shelf just above and behind the pouring pot and using angle iron to make a delivery trough between them. An added piece at the bottom to avoid splash should make it safe.
It has been in the teens every morning lately so its all still a dream. It shames me to remember how I complained that it was too hot to smelt last Summer.

[markinalpine]

I made a cover from a coffeecan end for my Lee 20 Pro by cutting a wedge to go around the valve mechanism, and a notch for my scraping, fluxing, mixing, stirring spoon: http://castboolits.gunloads.com/show...99&postcount=5
This helps hold the heat in and evens out the temperature.
Merry Christmas,
Mark

[Doc Highwall]

Another variable is how well the mould is vented. You can keep a record of what alloy and temperature each mould prefers for the next casting session.

[RandyGA]

I can relate to Tazman... Hi my name is Randy and I am a tightwad...LOL Sometimes you can't see the forest for the trees. I remelt candle wax to make new candles and have to watch the temp of the wax before I pour to make sure it is not too hot or cold....DUH...Why did I think lead for the bullets was any different. Anyway, after casting for 25+ years and getting frustrated...maybe that is why I have grey hair...Glad I found this board to get help. Yep if you can't afford the RCBS pro melt unit...improvize....going to build the PID temp control that I found on this board for better temp control. The Lee pots only have a bi-metal type temp controler which only sences radiated heat, not actual melt temp. So as your pot empties you have less mass to radiate and the pot just gets hotter to satisfy the bi-metal control. It is a simple but no way accurate way of controlling temp.

[stainless1911]

Lee 10 pounder. I have the Lyman thermometer in its clip mounted to the side of the pot. I cut a little slot in the clip to accept one of the 3 screws on top, and I keep the thermometer stem almost an inch away from the bottom of the pot, so it only touches the molten lead. Its set at about 4-1/2, for a temp of about 675*F.

[BSkerj]

I was able to pick up a old Lyman bottom pour at a local pawn shop. Owner did not have a clue how much it was worth since it was missing the cord. It also had a Lyman thermometer stuck in the middle of it. I offered him 12.00 for the pot, cooled lead, and thermometer and went down to the local Goodwill and got a cord for .50. It has been going strong ever since. To make a long story short..the thermometer alone was worth the 12.00. I cast mine between 675 and 700. I noticed a big difference in bullet weight though between ladle and bottom pour. Ladling just seems to keep the weights more consistant for the heavier bullets.

[Tazman1602]

Thanks for all the replies guys. Guess I'll try to turn down the heat a bit more and see how the casts look.

Some really great ideas!


I know BruceB, NOE, and a few other mold manufacturers have posted temps that their molds like mostly using WW lead but I haven't been able to find the posts.

I've got a written record of how my molds like to be poured, it's just strange. Some molds (we're talking 2-cavs right now) like to have the front bullet poured first and some like the rear cavity filled up first. HP molds are another story as are multi-cavity molds.

I'm getting a clue here as to the Lee pots. GENERALLY...........REALLY generally, around the 4.5-6.5 range once the temperature has stabilized, on the dial on these pots is going to put you in the ballpark for making great pours. Anyone who does_not have a thermometer or PID and has a lead pot give it a try and let me know how it goes.


Here's what we have so far:

1. Keep your lead pot as full as possible to avoid swings in temp, let temp stablize after adding any new lead including that which is pre-heated

2. Casting temps according to the members range from 650-750 degrees depending on alloy.

3. Keep a WRITTEN record of which mold likes lead at which heat best -- boy that's a GREAT one Doc!

4 -- I *think* this one was posted by WickedGoodOutdoors but if you want to keep the tin in your mix above 725 is too high. The reason you get all those "colors" sometimes is because your melt is way overheated.

5. The Lee lead pot dials are only for reference only and are no good for gauging heat at all unless you're an experienced caster and even then...........well, look at ME...................

Keep the information coming guys and I'll try to keep up with you on the list. Feel free to tell my I'm full of poopy if I add something stupid to the list..................

Many Thanks,

Art

[John Boy]

Reading about casting temps on this forum, the use of thermometers, and the fact I can't afford $350 for the RCBS melter I would like, and not wanting to spend $50 on a thermometer I just trudged along.............until a week or so ago.

Then I found a place that I believe makes the Lyman and RCBS 200-1000 degree F thermometers but their price is $19 -- that I will gamble on.

Taz ... where have you been for all these prior years? Every time a question comes up on various forums about 'What thermometer to buy,etc?' I keep posting the same answer about Tel-Tru, including here on Cast Boolits many times. A lot of bandwidth would be decreased if the Tel-Tru thermometer was just posted as a Sticky on the various boards. Here's my latest 13 December post on Wyoming Schuetzen Union ...

Why buy a Lyman when one can buy direct from the company that makes the same ones sold by Lyman, RCBS, Brownells, etc with the mark up for their name on the dial...
Tel-Tru LT225R BIG Green Egg/Grill Dome/Kamado Thermometer ... for $19 v $35. The thermometer is accurate +/- 1% full span ASME B40.3 Grade A standard per Tel-Tru

As for the 'clip', when I bought mine years back, it came with a spring clip that hooks on the edge of the pot.

Now, did you read the instructions that came with the Tel-Tru? Every bi-metal thermometer has a band on it. If the band is not kept in the melt - Incorrect temperature readings. I also have two electronic digital K-Type probe thermometers that are very accurate. There was a post on Cast Boolits many years back about them at Harbor Freight, for sale at their stores only. Accurate within +/- 2 degrees. Bought the stainless steel probes off eBay for a 'song'

Well, as they say ... "Better late than Never" Glad you "found a place" about the Grayslake, IL company that makes excellent thermometers, probably the best in the Industry. Did you find the Tel-Tru on your own or did you read about it somewhere? Like maybe the 6 times I posted about the thermometer here on Cast Boolits ... as far back as 2006!
Anyway, Happy Casting Now!

[Tazman1602]

LOL!

Hey John,

Man I don't know where I've been. Like I said I searched the forum (google actually works better than the search function on most forums....), read the stickies, etc and had never come across the Tel-Tru thermo until I posted a couple of weeks ago.

Yes, I'm a big one for "RTFM" (Read The FANTASTIC Manual...) and I do keep my thermo inserted past the band, I haven't checked calibration yet but have nothing to compare it to as of now.

I agree with the sticky which is why I started this thread. A lot of responses I see to new casters start with "READ THE STICKIES! DO YOUR RESEARCH! SEARCH THE FORUM!" with absolutely no clue as to the answer of their particular question.

I realize a lot of us on this board (and I'm a relative newbie here..) have been casting for some years and the questions from newbies are redundant, but blasting them for not doing their research does_not promote casting nor does it promote them to donate money to keep this forum going. I believe we should help them out as much as we can and I alway attempt to although I do fail miserably at times.

I found the thermo by doing a google search -- I thought it was a sham at first so I posted and got the answer I needed. I did NOT find a ref to this on any post I read...........and it's cold, snowy, and deer season is over so I'm either casting, on this forum, or working.............which is never enough (work that is.....).

I never ran across any of your posts man.................

I've got a makeshit mount for my thermo but am looking for better ways to mount it right now. Went shopping yesterday but didn't come up with anything yet. Ideas welcome, I don't like the little clip that came with it sticking down in the lead and I don't leave my thermo in the pot when I shut it down.

Art

[markinalpine]

"RTFM" (Read The FANTASTIC Manual...)!
Is THAT what that means?
I that those were those guys running aroung up in the Yukon in riding boots, red jackets, and Smoky Bear Hats.

Merry christmas,
Mark