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Rottweiler
12-26-2006, 10:09 PM
About what temperature or temperature range would be considered "optimum for casting boolits?
I know too hot is bad. ie tin and antimony like to separate out of the mix AND takes too long to cool AND makes "frosty"boolits. Too cold is solid not liquid

Thanks guys

9.3X62AL
12-26-2006, 11:05 PM
It's kind of a balancing act for me--involving the "heat sink" properties of mold--its material, its cavity size and number, in balance with the alloy temp--casting rate--environment temp, and resulting quality. I vary between 675* and 750*, adjusted to the above circumstances and variables. It would be difficult to pin down and "ideal" temp for all molds, but your methods might lend themselves to a given temp with a given mold--and recorded for further use.

Lotta variables to this question.

44man
12-26-2006, 11:13 PM
Hot is not bad! Even frosty is OK. Depends a lot on the alloy. Hard alloys can be cast a little cooler then pure lead but I never go under 750 to 800 degrees. Larger boolits even hotter.
The speed you cast has a big bearing on it too. Cutting the sprue too soon is not good and I wait an even time to cut, but from then on, my speed is constant. No lolygagen between pours. Slow down on the cutting and hold the ladle against the mold for a good time but make everything else fast. The secret is to make all times the same and keep the blocks hot.

John Boy
12-26-2006, 11:24 PM
Rottweiler: The gents have given you the good words. Might add, once an alloy melt of various metals is in the pot ... none will separate

One of the best articles on how to cast is ... http://www.longrangebpcr.com/8Phases.htm

Dye
12-26-2006, 11:53 PM
Rottweiller
Most moulds will cast the best if you keep the cavity temp around 325 degrees.

Be carefull Dye

NVcurmudgeon
12-27-2006, 12:02 AM
Rottweiler, cockapoo servant here. You have gotten some great advice already. As Deputy Al alluded to, moulds are very individual. Each will have a preferred casting temperature for making its own best bullets and maximum productivity. Even the casting rhythm of the individual operator will change results. I keep a record of what temperature each mould prefers, IN MY HANDS. The last few years I have been using an RCBS thermometer, with about the same results Deputy Al reports. for many years I used other signs to regulate temperature; sprue freezing time, rate of dross formation, and the glow of the bars of my Coleman stove grille. That was much like the ancient Polynesian navigators keeping their course, not by compass, but by watching the wind and waves.

felix
12-27-2006, 12:02 AM
Also, a mix once fluxed real good, might or might not stay in "solution" over time. The rule of thumb is to assume your mix is good and weigh your first real good boolits with the last of them from the same pot, at the same temp throughout, without the addition of sprues or other lead. If the boolits remain the same identical weight within an established tolerance, then the solution remained as a solution. When dealing with exotic elements, like copper, constant stirring is required, say after every 10 mold cycles. The funky thing is that we normally do not know the elements in a mix, but we really don't care for most applications. ... felix

georgeld
12-27-2006, 04:28 AM
Whole bunch of good advice and it seems we all do it differently yet about the same.

I use a bottom pour in Lee's six cavity molds now. Keep a couple 1# ingots on the rim of the pot to preheat and when there's room enough for one I slip it in real gently. Using the Lyman thermometer I stop casting when it gets less than 700. A couple times' I've gone to potty or otherwise been away afew minutes and seen it get as hot as 900 with a full 10# pot.

I drop the sprues back in the pot as they come off. When it does get less than 700, that's when I make a quick eyeball of what's been cast since the last time and drop them either back in IF the top has frozen up. Or into a can for rejects.

I drop them all into a five gallon bucket of water. One day when digging I ran across a parts cleaning basket the just fits into a bucket. That's been a great improvement from fishing around the bottom of the bucket in the cold water picking out the castings. Now I just pick the basket out, hook it on the rim, let it drip while picking them out. Wish I'd thought of using this basket ten yrs ago.

Frost is a good help in holding a bit more lube on the slugs. I use Lee's Alox and don't have any problem with leading but, my metal is scrap bullets from an indoor range and it's hard as cast. Never leads my bores, but, I don't load fast shooters either.

Do enough of it and you'll settle on your own system like most of us have.

Good shootin,

Bret4207
12-27-2006, 08:12 AM
As Bill said, you'll have to see what works for you and then WRITE IT DOWN! I've lost a lot of time and energy re-learnig what each mould requires because I was too lazy to write it down. Save yourself some headaches and get it the habit. FInd what works best with each individual alloy mould combo and jot it down.

I cast hot and worry a bit if I'm not getting the occasional frosty boolit, or all frosties for that matter. My GB 358-260 Bator 6 banger mould wants really hot alloy and all the boolits are frosty. It's happy, I'm happy and I wrote it down. Frosty works fine for me. If the appearance bothers you, someone here stated a quick swipe of the loaded round with 4/0 steel wool will shine it up a bit.

Rottweiler
12-27-2006, 09:22 AM
Thanks guys. Santa brought me an RCBS themometer and I was thinking that having a "set temperature" on it would help smooth out the process. Georgeld's setup is very similar to mine. The WRITE IT DOWN idea will probably help me as much as anything. You guys are right about each mold having it's own personality when it comes to casting speed and I'm sure temperatur has to play into that personality too

Tracy
12-27-2006, 10:16 AM
My Lee bottom pour furnace has been stuck (literally) in the "WAO" position for the past couple of decades, so I cast hot. I use wheelweights, perhaps with a little solder added, and I adjust my casting speed to the needs of the mould. Lots of times, once the mould gets up to full temp and I have to slow down, I start cycling a second mould during the cooling periods. This applies mostly to heavy bullets. Light bullets don't usually get hot enough to require much cooling time.

Bret4207
12-27-2006, 07:13 PM
When I got my thermometer I found I didn't use it like I thought I would. I figured I'd find "The Perect Temp" and then I could cast like crazy and all would be well with the world. I had so much faith in my theory that I thought it might even cure male pattern baldness and fat women in spandex. Alas and alon, such was not to be. In fact I find I use it more to keep track of whether or not the pot is cooling too much as I add sprues and ingots. I rarely even look at it once a good rythym is going. I did use to determine approximate dial posistions on my hot plate so I could come close to a temp. I think the dial I made is set for something like 700,750,800,850. Beyond 850 is pedal to the metal wide open and I don'yt use it much.

Someone else on another post some time ago said a termometer is one of the least usefull casting tools in reality. I think he was probably right.

Rottweiler
12-27-2006, 07:19 PM
Bret, Sounds like you had the same idea I have running through my head about the perfect temp. I'd like to hear more about curing fat women in spandex. Now there's a problem that needs fixing REALLY BAD...

Bret4207
12-27-2006, 07:34 PM
Millions have been made trying to cure the problem. Jenny Craig, Slim Fast, Lean Cuisine, etc, etc.