Optimum casting temperature

[8shot]

Still waiting for a Lyman Mag 25 (230v) furnace that I ordered from Optics Planet on Jan 24th! Don't even have shipping info...just replies that shipping is delayed. (Sold my Lee pot too early)

Anyway - in preparation looking for the optimum casting temperature for the MP 360-640L brass 4 cavity mold using Alloy 2-2-96 from your experience.

Found one post where 745F was the sweet spot for that 130gr HP bullet.

Molds have been seasoned and the Lyman MAG 25 has a mold heating shelf.

Thanks

[Rcmaveric]

My opinion.... as high as it takes for good fill out. I normally cast around 800 to 950 F

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[Mitch]

745 sounds like a good place to start.A hot plate with metal can over the mold like an oven will help alot to.the brass molds with pins need to be hot toatart out or it will take half the pot to bet the mold up to temp.

Good luck with the order from optic planet.You realy need to watch when you order thngs now days if things are in stock.Optics planet has been the worst fore me they dont tell you or know cuze they drop ship alot.

[ShooterAZ]

725 is usually where I start out, and then adjust from there depending on the alloy. 725 is good for me for the most part.

[bangerjim]

Low 700's is a go STARTING place. Brass molds like to run HOT!!!!!! But you cast at the temp that gives you the best drops, not by some listing in some post somewhere. Sounds like you are a beginner and may have gotten lost in the weeds of too much reading and technical goop without any hands-on equipment to play with.

Casting temp is a wide and varying target. Only time and experience will let you know what YOU need for YOUR alloy, YOUR molds, and YOUR casting techniques.

Practice makes perfect, and in this hobby, "perfect" is a constant goal we all struggle to achieve!!!!!

And bad drops always remelt..............very easily! :lovebooli

Good luck and happy casting. :2_high5:

[mdi]

Depending on alloy, mold, tempo, bullet size I use between about 680 degrees to 725 degrees. But I don't have any brass molds, just aluminum and steel. I use a dial thermometer in my old Lee pot and the temp stays pretty constant and my starting temp is around 700 degrees...

[Mal Paso]

My MP 432-640 preheated on a hotplate starts at 700F but I drop that 10-20 degrees as needed to keep the sprue freeze time from getting too long. 360 is going to need a little more heat. A slab of steel on the hotplate to warm those pins helps.

[JonB_in_Glencoe]

2-2-96
I usually start with the PID set at 680º
and for a brass mold (brass holds heat), if casting/dropping is going swimmingly and I am able to cast fast, I'll turn the PID down 10 degrees or so...maybe even down to 650º if the mold tells me it wants that, and with Brass molds, I usually have a fan blowing into the "drop area" to cool off the mold.
That's my 2¢

[jimb16]

MDI pretty well hit it on the head. It depends on the mold and the alloy. Different molds require different temps depending on what they are made from and the mass / heat retaining ability of the mold. Different alloys also require different temps depending on the flow characteristics of that alloy. All anyone can tell you is what worked for them and give you a starting point for experimenting with your particular mold/alloy combination. Have fun! and don't give up if you don't get good results right off the bat.

[guy_with_boolits]

beware too high and your sprue will stay molten internally and will smear when you open it

also above 800 to 850F lead fumes start evolving (there is literature on this in another thread, referenced from solder pots in industry)

[Shuz]

Based on my thermometer readings, I get great results with my 10:1 alloy(ww:lino) at from 690 to 715 degF. This temperature range seems to work well for me with steel, aluminum and brass moulds.

[M-Tecs]

No such thing as a recommend one size fits all sweet spot. As stated that depends on your mold material and size, your alloy and your casting cadence. I tend to have a fast cadence and I normally am in the 675 to 725. I do use both a PID and a thermometer.

[Soundguy]

My opinion.... as high as it takes for good fill out. I normally cast around 800 to 950 F

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I'm glad om not the only one that casts with melt that hot. I like good fill out and non wrinkled bullets without having so much tin that you are casting solder. ;)

[Conditor22]

I cast between 680 - 720° and just add a little tin if I don't get the fill out I want. The hotter you cast the more the boolits will shrink when they cool. With pure lead, I cast around 750°.

As previously noted when alloy and mold temperatures get too high you run into the chance of the sprue hardening before the boolits do :(

[JeffG]

I cast between 705-735 depending on the mold. Bigger heavier bullets put more heat in the mold so the casting temp doesn’t need to be as high. After last pour in the mold I try to keep heat and rhythm where the spruce will flashover in about 5 seconds but drop from mold easily and still be soft and shiny, but frost within a few seconds of dropping. I also preheat on a hot plate with an old skilsaw blade on it.

[kevin c]

I start my 95-3-2 alloy for my preheated 8 cavity aluminum 9mm molds at 730°.

In addition to all the other variables mentioned, I find that, casting out of doors, air temperature and wind conditions also change how much I need to change that PID setting.

[Tazza]

I cast as cool as i can to get full fill out and without spout freeze. I have found that depending on the alloy i'm using, 350 to 360c does the job for me.

At this temperature, i can run my casting machine quicker without the mould over heating.

[RU shooter]

Guess I'll be the odd man out . From day one I've never used a thermometer or even had a dial control on my melter . I use an old 1970's 4 burner elec. range top and a insulated SS pot and ladle dip I have three buttons that control the heat high medium and low when the alloy goes liquid I go to medium heat button and just leave it till the pot gets low . I've cast a lot of bullets this way and never had an issue I've found more issues with mould temp than alloy temp .

[Soundguy]

agreed.. high mold temp is bad.. frosting... low mold temp.. early wrinkles and freeze.

I cast outside.. so as said earlier.. tend to cast hot. I use an rcbs thermometer.

[The Dar]

I had been casting at 720 but not getting good fill out. I do add a little tin to the mix. Been playing with temps and I've found that 750 gives fantastic fill out in my boolits. YMMV

[Multra]

6-7 on the dial on my lee 420 seems to cast well, no idea what temp that comes out to, never really worried about it too much.

[fredj338]

I doubt there is an optimum temp for casting. it is alloy & mold dependent. I run about 740-750, it just works for everything.

[ABJ]

I doubt there is an optimum temp for casting. it is alloy & mold dependent. I run about 740-750, it just works for everything.

To expand on this thought, pure lead-800 degrees, 20:1-800 degrees, Lino=low to mid 700's, everyday alloy like 2% tin and 3 to 4% antimony I set my mag 25 at 780 and add 2 lb ingot as often as it will take it.
If I am using a Lee dip pot I go a little higher because the recovery time after adding alloy is longer.
Keep in mind whatever the melt temp is and your adding alloy, unless you wait for the pot to recover your casting temp is between the lowest temp(adding cold ingots) and whatever it recovers to before adding another ingot.
Tony

[Thumbcocker]

I like it to be in the 70's

[Greg S]

All my brass HP molds run about 700-730, my difficult ones being 32 cal which require pressure pouring after a hotplate pre-heat until I get enough heat in the mold to just cast normally.