Bullet casting improvements

[unfy]

Sat down tonight and decided to get more serious about bullet casting.

Did a little bit of reading, a bunch of video watching.  Basically, it was time to move from utility casting (copper plating fodder and PC fodder etc) into something I could do for actual reloading.

So... re-worked casting work area a bit for smoother flow / less movement, and decided to try different procedures (a mix from someone's speed casting techniques and a video).  That video would be:



Don't care for the guy's attitude too much, and with a regular $20 lee mold it's not wholly applicable (ie: can't just nudge some hollow point pins)... but... in general things went much better. 

Upped temperature on pot a little (lee 4/20... set to 7 instead of 6).

Got mold a bit hotter than I normally would have, in particular the sprue plate. The first half dozen breaks using video guy's method still required tapping sprue plate clear and tapping bullets out.  After that, sprue plate was hot enough to not require tapping.

Time between filling mold and cutting sprue reduced to just 2-4 seconds.

Hotter sprue plate and molds seem to nearly completely eliminate the need to tap things with a wooden hammer handle blank.  Hand breaks were easy and clean, and bullets typically fell out of the mold with a slight jiggle.  Only one in 10-15 breaks would require a tap from wood.

The use of the casting pot foot as a heat sink to cool the mold for quicker progression is a great idea.  Faster break, more even temperature control, etc.

Towards the end, I did have some slight sprue plate overheating issues (smearing instead of a clean cut).  Just for fun: I forgot to setup a sponge so ended up slobbering all over a sock to act as a coolant.....

Differences from what I do to what the guy in the video does:

I break the sprue over the pot so the lead goes directly back into the pot.  I will prolly stop doing this in order to help reduce splashes.  Also, due to this, I don't "fling" anything heh.

Wasn't dropping into water (in particular with PC and the 400 degree bake... quenching gets undone).


Prolly increased casting rate by a factor of 5-8, and my reject count is sitting at 10 out of the ~1000 cast.  I imagine not tapping on everything a bunch for every break is better for the mold too.

Yay.

[unfy]

I'm gonna go ahead and fiddle with alloy stuff on my next go around of casting (and after I get some HP molds)

Some lead free soldier will go into the pot to bring hardness up.  Not terribly expensive (not terribly cheap either), but easy to measure and of known tin/antimony contents.  I was hoping to avoid fidlding with alloying stuff, but it seems like it'd just be a wise thing to do.  Since I'm not producing super high quality lead bullets (see powder coating heh) ... I'm not too worried about getting ultra consistent hardness between batches of bullets... but will endeavor to keep it close anyway (should just remelt the ingots, remix alloy, and recast ingots but whatever).

[bkoenig]

I need to watch that video when I get home tonight.  My casting works ok but I could use some improvement to speed things up.  I usually cast with two molds at once and let the sprue cool while emptying and refilling the other mold, but that wastes a lot of time setting down and picking up molds.  Having a way to cool the sprue and using a single mold would speed things up.

[unfy]

I found on my ~175-180gr .401 lee mold... I don't need to cool the sprue really.

The video here, and from what I've read...

* Ya run the lead on the warm side.

* fill mold

* set mold on the base of the lee pot (or some other moderate heatsink)

* count between 2 and 4 seconds

* break sprue by hand (for me, i was dumping sprue back into pot, this is gonna change to spare pan to avoid splashes)

* break mold and dump bullets out (typically didn't require any tapping on the pivot bolt/nut)

* immediately go back to filling mold


Due note, I am using smoked molds.

To me, this seemed counter-intuitive... but my bullet quality actually went *up* with this method.  Placing the mold on the casting pot base (or similar aluminum heat sink) sets the bullets and cools off the mold 'just enough' to keep ya casting for extended periods without having to fiddle with mold temperature management (ie: getting fins/etc).  If it looks like your mold is getting too hot, take your '3 second' count on the heat sink to 4 or 5 seconds for a few breaks.  If the mold seems too cold, only do a '2 second count' maybe.

And for the second thing to address - sprue plate temperature. Ya actually want the sprue plate pretty hot when casting in this method.  Ya wanna be able to cut the sprue plate open by hand, and a cold sprue plate makes your sprue harden more quickly, making hand breaks more difficult if not impossible.  I am not sure, but I think the shorter amount of time the lead is on the sprue plate helps keep plate temperature where ya want it.  As I noted with my original post, my sprue plate actually didn't get too hot until near the end of my casting session.  That is, I didn't get any smear cuts on the top of my mold until the last bits of casting... so having the normally required wet sponge near by wouldn't be a bad idea. 

I did have a couple bullets get a dent in their nose... so.... that's something to be aware of.  My current drop place is a cardboard box (from midway no less) with some old jeans in it.  I'll prolly move to a bucket / plastic coffee can of water covered by an old shirt and slit in it.  With the powder coat, I doubt the hardness gained from the water quench will matter (since they're gonna be baked at 400f for 20min later)... but... should stop any deformation stuffs as well as possibly just being easier to deal with.

After adjusting to my routine, it wasn't quite as fast as the guy in the video, but it was getting darn close.

Keeping things relatively hot and being able to break everything open by hand improves speed a lot. Not having bullets stick to the mold is really nice.  Fewer motions, no change-outs-of-tools-in-hand (ie: mold -> wooden/plastic hammer -> mold), and it's easier to get a rhythm.


The only question I can think of to discuss:

Is there a real and identifiable reason to let bullets cure in the mold longer ?

[bkoenig]

I think if bullets sit in the mold longer they can drop easier, since they shrink as they cool.  When I cast for my Blackout I have to let them cool longer because that .309 diameter 245 grain bullet is so long and skinny that I have actually had them bend when I drop them too soon.  I drop into a bucket of water, covered by an old shirt with a slit in it.  That seems to work really well.

I drop my sprues into a popcorn tin, one of those big ones that Christmas popcorn comes in.  I don't like dropping them directly into the pot because I feel it can introduce contamination.  Instead I cast until I have a big pile of sprues, then dump them into the pot and flux again to make sure it stays clean.

I'll have to give this method a try.  Right now I use a 1" dowel to cut the sprue.  If I can speed things up by just using my hand that would be nice.  I'm sure I am wasting a lot of movement.

[unfy]

I think if bullets sit in the mold longer they can drop easier, since they shrink as they cool.  When I cast for my Blackout I have to let them cool longer because that .309 diameter 245 grain bullet is so long and skinny that I have actually had them bend when I drop them too soon.  I drop into a bucket of water, covered by an old shirt with a slit in it.  That seems to work really well.

Good to see another vote for bucket & shirt-slit.  Will change to doing it this way then.

I drop my sprues into a popcorn tin, one of those big ones that Christmas popcorn comes in.  I don't like dropping them directly into the pot because I feel it can introduce contamination.  Instead I cast until I have a big pile of sprues, then dump them into the pot and flux again to make sure it stays clean.

I've gone got of the Christmas popcorn tins as well, but I've been holding on to use it for possibly making a back yard blast furance / foundary / forge / whatever out of (something to melt aluminum in etc). Tee hee

I get a blue oxidation layer / film on top of my pot after time goes on for a while.  Not entirely sure what that's about.  Might be dropping sprue back into pot, might not be.  I dunno.  If it dissipates  after switching to sprue-in-a-pan-or-tin... then... we'll know the cause .

I've not been too concerned about contamination - mold sprue is relatively clean and all that.  Maybe the blue means it's not, I dunno.

I'll have to give this method a try.  Right now I use a 1" dowel to cut the sprue.  If I can speed things up by just using my hand that would be nice.  I'm sure I am wasting a lot of movement.

Compared to long cool / set / freeze times on the 40s&w... I find the quicker cast method of dropping the bullets hot drops *far* easier than the long set times.  I dunno if the block (aluminum) shrinks faster than the lead or what exactly is going on.

With the long cool / set / freeze time, I'd have to hammer the pivot bolt/nut (often several times) to get the bullets to drop.  With the quicker casting... I only had to tap the pivot 1 in 10 casts or so... They'd usually fall out on just breaking the mold or with a slight jiggle.

Not entirely sure how to address the long / thin bullet ... other than maybe setting the mold on whatever heat sink ya choose might cause it to set quicker / better ? Depending on mold ?  I doubt some of the honkin saeco cast iron molds would care about the heat sink .

edit: typo/grammar fail.

re-edit:

Re: 1 inch down to knock things open etc

I use a wooden hammer/tool handle that was on sale for a buck.  Has a fair amount of heft to it and does nicely.  Any chunk of wood would undoubtedly work just fine heh.

I also managed to pick up a relatively cheap plastic tipped hammer for other reloading adventures (swaging comes to mind) ... but I imagine it'd do nicely for mold blocks too.

[bkoenig]

I get a blue oxidation layer / film on top of my pot after time goes on for a while.  Not entirely sure what that's about.  Might be dropping sprue back into pot, might not be.  I dunno.  If it dissipates  after switching to sprue-in-a-pan-or-tin... then... we'll know the cause .

I get that, too.  I think it's just natural oxidation from the heat.  With a bottom pour pot (in theory) all the crud should float to the top and the bottom lead should be clean.  I use sawdust for fluxing and I've heard of guys not scraping that off, just letting the ash float on top to form a protective layer.  I'm thinking if you drop sprues in it can force some of that oxidation down into the mix.  It probably doesn't matter one way or the other.  The biggest reason I've found for using the big tin is that I don't end up with chunks of lead all over (well, I still do, but not from the sprues).

[unfy]

(well, I still do, but not from the sprues).

LOL

And thanks for the heads up about getting the blue too.

While at the hardware store picking up a few misc things.... I looked at the lead free solder.

$25 for a pound seemed steep... but... that's actually par with ingots of the stuff or even cheaper).

Actual tin can be possibly had cheaper from 'dirty sources' (ie: roofing washers)... but... getting any antimony looks to be hard to do.

Soooo yeah, will be picking up the solder.

If ya chuck the entire spool into a 19lb pot, comes out to $25 lets you cast ~750 bullets. That seems a tad excessive, so I'll take other folk's results with stuff and try some approximations and what not.

Not having a BHN tester is gonna be kinda funky.

[66bigblock]

Not to hijack here, but why do you need lead free solder?

66bigblock

[bkoenig]

I bought 20lbs or so of Superhard alloy from Rotometals for about $100 and I'm very happy with the results.  If you spend $100 they ship it for free.  It has a very high antimony content (I can't remember how much at the time) so you don't need much to harden up pure lead.  According to the LASC site 3lbs of Superhard and 15lbs of stickon wheel weights is the equivalent of Lyman #2 alloy.  I'm using range scrap lead which should be pretty close to the nearly pure lead in stick on weights.  This mix is working really well in my 9mm, 7.62x54, and .38-55.  I'm using gas checks on the 7.62 but plain base on the others and getting very little leading.

By the way, the LASC (Los Angeles Silhouette Club) site is a treasure trove of information for bullet casters:

http://www.lasc.us/SuperHard.htm

[bkoenig]

Not to hijack here, but why do you need lead free solder?

66bigblock

It's made mostly of tin.  Tin gives you a little hardness and helps with mold fillout.

[66bigblock]

I have a bunch of 1 lb solder rolls I would sell, but not sure any are lead free.


66bigblock

[unfy]

As bkoenig said.... when using pure or scrap lead, adding tin helps with a bit of hardness and mold fill out.  Sharper shoulders / lube grooves, that kind of thing.

Tin can be had in various forms for various prices (hardyharhar) .... but antimony is harder to come by. 

Mixing lead with solder (ie: 50/50 lead/tin solder etc) can get a bunch of tin into your alloy.  Antimony is much harder to work with.

Soooo... you typically buy an alloy that already has antimony in it from some metal shop / foundary.  Some folks sell stuff you're supposed to purposefully dilute, others you can take a very hard alloy and mix it with your normal lead to soften the source alloy or harden up your own.

BK's mention of superhard is an example of something that is quite proper for diluting in lead.  Others will mix linotype into their lead to harden up stuff, etc.

Lead free soldier is 95% tin, 5% antimony typically (some are tin/copper, others have silver, etc).  If ya mix 19lbs of lead with a pound of this solder, ya get something that's 95% lead, 4.75% tin, and 0.25% antimony.

Superhard is 70% lead, 30% antimony.  Casting pure is superhard is out of the question, the bullet would prolly just shatter whatever it hit (or shatter in the barrel).  But, if ya mix 15lbs/3lbs, ya end up with close to 95% lead 5% antimony.  Lacks the tin, but ya get the brittleness of the antimony.  Superhard is designed to mixed by the caster to formulate their own antimony content in their own alloys.

At the $100 price break for free shipping, gotta buy 5 bars of superhard right now... which puts ya at ~25lbs of superhard and $115.  $4.60 per pound, which is far cheaper than trying to buy solder .

Granted, tin is $18-$20/lb in pureish forms.

[bkoenig]

The Superhard alloy is so brittle that I just whack the bar with a hammer to break off a chunk.  I do mix a little lead free solder into the pot to help with fillout, but I don't know if it's really needed.

[unfy]

As mentioned in the hollowpointmold.com purchase thread, I got an email back from Erik about a question involving the newer cast method I've lifted from other folks...

I say cast as fast as possible and only slow down to keep from getting smears on top!  Seriously, you can cast at a pretty good clip and just wait about a 5 count to break the sprue and just slow it down enough so you don't get smears or overheat.  Sounds like you have it figured out already.  The different metals shouldn't give any problems just make sure to lube the sprue pivot and sliding parts sparingly once
in a while.

Skip the setting the mold down, no need to keep it warmer than the actual casting provides after initial warm up.  Erik

Sooo... I dunno if the heatsink step is necessary (setting the mold on the base of the lee pot or something similar)  ... but it seems to be working for me so dunno if I'll change my routine or not.

[unfy]

Not to hijack here, but why do you need lead free solder?

66bigblock

We've mentioned mold fill out and hardness and other stuff.

Here's an example of the mold fill out.



While the color / shiny-ness of the metal is different, that doesn't really matter.

Note on the lube groves, shoulder to bearing wall joint, and hollow point noses that the tin-ified alloy has sharper corners than just the wheel weight.

For hardness stuff.... I attempted a 3LB sledge drop to demonstrate a difference, but that didn't work out so well heh... and I was afraid of breaking concrete.

Anyhoo, hardness ratings:

Element | Brinnel Hardness | Shear Hardness
Lead - 38.3 MPa  | 5.6 GPa
Tin - ~350 MPa | 18 GPa
Antimony - 294 MPa | 20 GPa

As you can see, tin & antimony have much higher brinnel & shear hardness values.  let alone what they do you when you alloy them

[unfy]

Oh, and just for a pointless instructional  / demonstration pic, when a mold is too cold vs when a mold is way too blazingly hot.

Cold on the left (note the "fat layers" look), hot crappy pot metal appearance on the right (let alone deformed).  The way too hot mold bullets are also far lighter (weight) than they should be....

[358156hp]

Guys, if you're casting hollowpoints with an alloy much harder than about bhn 10, your alloys too hard to allow expansion with most calibers. Often times, the bullets will simply fragment without allowing much penetration. Consider about 1:20 alloy for cast hollowpoints. Tin doesn't really harden lead alloys that much. Tins greatest benefit is that it reduces surface tension in lead-based alloys, allowing the moulds to fill out better at lower temps. Most of my cast hollowpoints end up around bhn 8-9, which is about the area for 1:25 alloy. I cast my regular bullets from range scrap with about 2-3% of 95-5 lead free solder to make it flow better, and I cast hot with most moulds, usually in the 800 degree range. My Hensley & Gibbs moulds seem to demand 650 for some reason.

[unfy]

Don't believe bkoenig has any hollow point molds ?

I might be the only one that I know of ?

I won't go hunting with cast bullets, and I won't be using any for self defense purposes.  My primary reason for the HP mold was to make powder coating easier ... thus punching holes in paper.

But, I'm running 20:1 for it at the moment and will prolly just use 20:1 as my generic alloy for most things.

[358156hp]

The only reason I mention it is because I recently encountered a fella who was casting hollowpoints from linotype, and was bothered because the bullets disintegrated when shot into water jugs. He was a bit proud of himself for believing he has discovered a cheap source of Glaser Safety Slugs. The guys an optimist, I have to give him that.

20:1s a pretty good all around choice, you'll be pretty happy with it.