Home Forums Reloading Bullet Casting Casting temps

I rently upgraded to an RCBS bottom pour that has temp control. I also recently got 3 new 4 cavity brass m&p molds that can do hollow points and other penta, flat, etc.

I mixed some alloy with a softer mostly lead from RNR that's supposed to be bhn 10. I used 18#s rmr, 2 pounds of mono type, and 2 pounds of a wheel weight blend that is 4 to 1 ww to mono.

I preheat my molds on a burner plate and ran the alloy at 750. After just a few casts my .452 mold was throwing beautiful 210g penta rn hps for my 45 acps. They cast well at that temp but are frosty. If I let the mold cool a bit they went wrinkly and didn't cast well.

Should I try to reduce my alloy temp or change my rythm? I don't really mind frosty because they powder coat well but I'd like to cast some beautiful Shiney bullets.

I've had a but more difficulty with my .458 mold casting 410g cup points. The bands sometimes have rounded edges and when I run it hit with 750 degree alloy I get frost too. It took a bit more work than the other molds and I'm still dialing my process with it but I've cast a few hundred that look pretty good.

Today I'm heating up the pot to do some 270g flat nose hammers in .432 for my 44 mags. I tried about the same blend but added an additional 2 pounds of my 4 to 1 ww to mono blend. I like the arsenic and a few things a bit of ww brings. My lino is testing as mono at only 72 % lead the rest is tin and antimony. I've got about 1000 pounds of it so I always seem to add a bit to any alloy.

What temp do you run similar alloys at?

Bb

I run my pots a lot hotter than most folks, 8-900 degrees. I don't care about frostiness (doesn't hurt a thing), but I do care about sharp fill-out and that solution cuts to the chase. The older I get the more I try to avoid alloys with antimony and arsenic in them, and am glad that I'm about out of stuff with those elements in them.

I thought powder coating precluded having to mess with hard alloys anyway?

Gnoahh, do you have any issues casting with aluminum molds at that temp?????

Nope. I do cast with two molds at a time to slow the cadence. Aluminum heats up fast but also cools down fast.

I just finished casting some 270g wfn hamers at .432 for my 44s. Some of them look pretty good but a lot were a bit rounded on the edges of the center band. It looks like they just didn't fill out to a aquire break at tge corner.

As far as I know getting things hotter should fill out the edges better. I tried some cast at 710 and some at 750 but didn't notice much difference. Maybe I'll crank it up to 800 and try again. I'm keeping my molds on a hotplate.

My .452 mold is a powder coat design with no lube grooves so it's easy to cast with and just rained 210g penta hps. I'll put the flat nose pins in it and cast some 230g round flat noses soon too.

I'm going to order a 10mm mold soon in a 200g or so round flat nose. I've just been dragging my feet as to which one.

Bb

Try a half inch piece of solder that ha silver in it. A one pound spool will last you a long time.
I’ve got the NOE 200 grain mold for my centimeter sized pistols. I think Mihec made a nice bullet for the 40/10mm. It’s out of stock but an email to him can get you a mold

Yup I run 800 and above with wheel weights and just a bit of tin. Good fillout, mild frost. I have a half fast theory that the frost provides a home for the thin coat of Lee Liquid Alox, since I am too lazy to properly lube like a normal person. Contrary to all logic, the thin coat of alox works with zero leading in a 29" bbl 8x57 at 1600 fps. They say tin is liquid at 450 and wheel weight at a little over 500...so 800 sounds like overkill...but it works for my rifles. Aluminum molds exclusively.

Hollowpoint molds are tricky to cast. You need to run them hot and fast, but not so fast that the bullet is damaged releasing from the mold or hitting your towels. If you want to cast them at a lower temp so they aren't frosty, add 2% tin which as I recall is 2 1/2' of a roll of lead free solder.

Speaking of Tin, last Tine I bought I ordered through Wal-Mart, FREE Shipping............ who would have known.....

Ok, I'll bite! Out of curiosity I just now did an online search of Walmart for "tin" and got a bazillion hits for tin cookware, including "Muffin" tins. (Were you born in a Walmart?! )

Casting temps? Buy a lead thermometer. Pure lead casts well at 800*. 30:1 pb/sn at 750*. WW alloy does fine in the 650-700* range. Preheat your mould.

I tend to cast on the hot side, 800-850 but I don't cast as fast as many others. Frosting doesn't bother me, the powder coating covers that, what I'm looking for is good fill out & for sure I want flat bases. Remember the bullets are going to anneal down a bit in the toaster oven unless you water quench right from the oven. I only do that when I go to Africa. Also I prefer to not use GC's except for my 357 Maximum & my hot 32/20 loads.

Dick

I often see people recommending adding anywhere from a few inches to a few feet of solder to get enough tin in the mix. If I have 25 pounds in the pot wouldn't I need to add 4 ounces of tin just to get to 1% tin? The tin I'm seeing available is pretty expensive often at around $30 a pound. Going for 2% would run me about $15 a pot extra.

My large stash of monotype has lots of tin in it but unfortunately it has even more antimony. Usually adding some of it to ww or rmr lead gives me a pretty good casting alloy. My only concern is now that I'm making hp bullets and wanting them to expand I think I'd prefer to just use my rmr bullet scrap bhn 10 range lead and just add a bit of tin. I can use my ww and mono blends for my flat nose bullets.

Bb

Just a simple google-fu search for tin and got a walmart 'hit'..........

I now have the wifey order my tin......

https://www.walmart.com/ip/Tin-Ingo...n0Atco2xhJIIyd5McjPxIkl00L0aAhr0EALw_wcB

$30/lb. is a little more expensive than Rotometals ($24.99), but I see Walmart would send it to me with free shipping. Not bad. I buy the small nuggets of tin from Rotometals, $26.99, because it's easier to meter them into small-ish batches of alloy.

I was at a gunshow where a vendor had a stack of one pound tin ingots selling for $20. Should've bought more than I did but he couldn't guarantee the purity. Nitpicking, for sure, because on the other hand my "pure" lead isn't certified anyway.....

I don't know about casting with brass molds but I cast at 720º using both Aluminum and Steel molds and straight wheelwright alloy.