New to casting- a few questions.

[CoolHandMoss]

I've been lurking on the forum and picking up a ton of info for a little bit now. A few questions still elude me when it comes to casting. So I figured I'd start a thread and get some direct input and try to get up to 30 posts so I can post a WTB thread while I'm at it!

It is clear that there are a ton of variables involved in working up a good boolit and a good load for it. Hardness of the boolit, diameter, lubricant, powder selection, powder charge... and so on. Question is, when you don't have a well established load that you are just adjusting one parameter for, were do you start? Which variables are least impacted by changes in other variables? If I have a boolit I want to develop a load for, do I experiment with different diameters first or different powder charges first? Different types of powder or different amounts first? I would expect that starting .001 over with a middle of the road lube and a powder popular for that round then tuning powder charge first would be good. Then tweaking diameter (up 001, down 001...), playing with seating depth whatever may be possible, then working on trying slightly more or less viscous lubes, then repeating the process with the next boolit would be the most sensible course of action?

Related question: I have a few different books. I am currently looking at a Lyman 49th and a second edition Lee book primarily. I am frequently finding rather large differences between what different books give for starting/max loads with a given powder. If the boolit is of the same weight but a different design that would explain some of the difference, but I have run across a couple examples of max recommendations in one book that were under the starting recommendations in another book for a slightly different boolit of the same weight. What is an advisable approach to this situation, and what part of the picture might I be neglecting to consider here? Seeing things like that make me skeptical. I suppose one can never go wrong with starting at the lowest published load and working up slowly watching for pressure signs with each increase up to the highest published max, but is this variance between publications just par for the course?

Lastly, pour temperature and mold temperature. I have seen people say they like to pour very hot all the time, 800-850, many say 700-750, some say under 700, my Lyman lead thermometer shows a recommended range up to 750, some heat molds between pours, some cool them... I understand that the type of mold material and the total lead volume in the cavities vs. the amount of mold material in the block affects how much heat the mold takes from the pour and all, but what I'm trying to balance is how hot to keep the mold vs. how hot to keep the pot. Starting with a hot pot gets the mold warmed up faster so I get nice boolits with no wrinkles. Then once the mold gets good and hot I start seeing bad sprue cuts where it looks like the sprue plate kind of drags some lead out of the middle of the boolit and leaves a little divot in the base. When I see this I turn the pot down and try to maintain somewhere in the neighborhood of 750. If the pot gets much cooler I get more prone to wrinkles. If I go to fast though and don't let the sprue set for long enough I still get these divots instead of clean sprue cuts. If I try to cool the mold down by leaving it open for a bit between pours, or trying the two mold technique, then I run in to wrinkles or incomplete fills and rounded edges on the bases of the boolits. Of course turning the pot down much more, below 700 usually, ends up making it very hard to get a good fill. I tried a cool pot, 600-675, and just keeping the pace up as fast as I could but that resulted in boolits that were not round even after being dropped on a bench cushioned with a towel because they hadn't set up enough before dropping. This is all with two cavity aluminum molds as that is all I have at this point. All that said, I am able to crank out plenty of decent boolits but this game of chasing a good fill and a good sprue cut seems to be never ending. I can't find a balance that gives me good consistency. What advice do the seasoned veterans of casting have to offer on this matter? Is this less of an issue with an iron or brass mold?

[Bad Ass Wallace]

Firstly CoolHand, welcome to the forum.

You seem to have grasped the basics, but now need to work on the refinements. My equipment is very simple and has served me for over 40 years. Because I cast in bulk, I use a pot that holds 80lb of alloy and use up to 7 molds at a time.

With a small 20lb pot, using 5lb for casting will reduce the total amount by 25% and without turning the heat down, a significant rise in casting temperature will occur, affecting the quality of the cast boolits.

With a huge pot, once a good casting temp. is reached, 5lbs of cast has very little affect on the melt and the quality of the cast boolits produced. I shoot a lot of BPCR and can produce quality boolits to within +/- 0.2gns with a reject rate of as little as 5 - 8%.

Controlling the temp is so important because different molds (Aluminium, Brass, Cast steel) have different coefficient of thermal expansion which means that an aluminium mold, when too hot, may produce oversized boolits when compared to steel molds.

My equipment consists of a large pot, a gas heat source and a range of molds that cast good boolits. From the picture, you can see that I have 3 large pots that have been mixed with alloys for rifle, BPCR and Muzzleloaders. Then I have hundreds of ingots that I use to 'feed' the pots as I am casting.

[mehavey]

Pure Lead: 800
30-1 Alloy: 780-ish
Lyman#2: 700

As far different bullet/same weight loads -- Look at the OAL for hints as to pressure effects.

Nail the diameter down first. Pretty simple: Groove +1/2 thou

Hardness 2nd: as Soft as possible w/o leading

Low loads: as SOFT as possible w/ FASTer powders

Lube: Failsafe LLALOX and or PowderCoat




.... the rest is all ART.

[CoolHandMoss]

Thank you for the response. I do use a small pot and that is a good point to consider. Perhaps keeping the pot more full will help keep my pours more consistent.

[RickinTN]

I did read most of your post but to reply to all of it is beyond me, at least right now. One thing which stands out....When you start getting wet sprue cuts don't turn the pot temperature down, just wait a little longer to cut the sprues. You'll find and sometimes have to adjust your rhythm.
Good Luck,
Rick

[CoolHandMoss]

Thanks gentlemen. This is all very helpful. And yes, long thread. I don't blame you for not getting all the way through it!

[country gent]

Do some research in the loading manuals the more the better. look over the various powders for your bullet make a note of he most popular in each manual. A powder that shows up in the most manuals is a good place to start out. Start low and work up in increments.

There is the Audette method of working up a load ( more useful with rifles ) where you load 1 round at starting and 1 round every .2 grn up to max or just under. zero rifle and shoot these watching and making notes where each hits. What you will should see is a line of holes walking up the target and at several places there will be 2-3 rounds clustered together. AT the desired velocity test that cluster at the mid point of it. The clusters are where that powder is leaving on dead node in the barrels harmonics. This work finds a load that you can be +/- .3 of a grain or more and still go in the group.
If you have or have access to a chronograph watch the extreme spreads and Standard Deviation of the test loads, along with the groups. test at the longest ranges you can with in range.

As to casting. temps vary with ambient temps and winds breezes, alloy, moulds material, pour strength speed, size of the bullet and cadence. This is a learning curve that improves as you gain experience. A 22 cal 50 grn bullet just doesn't have the mass to over heat a mould while a 45 cal 550 grn will quickly overheat a mould with a to fast cadence. Another is the size of sprue you pour. smaller dosnt but the heat into the plate that a bigger one does. Ladle casting try not pouring for a sprue size but hang the mould over the pot and pour the full ladle in letting the excess run back in the pot, this 1) keeps the base hot much longer 2) allows the mould to fully fill and off gas better removing voids and wrinkles 3) it gives the bullet time to fully fill as the bullet shrinks.

With the right temp on the pot fill the mould watch the sprue you will see it molten then solidify then a "frost" comes over it give it a 3-8 sec count and cut the sprue. Adjust your pots temp to your cadence. Wrinkles up tem 20-25* starting to frost lower 25* dont stop casting let it adjust as you go.

I cast bullets in the bigger range 38 cal 360 grn up to 45 cal 550 grn, use the over pour with a ladle. ore heat the mould on the pot and then throw the first 10-12 cast back in the pot "just because",at te end of a session Ill have 400-500 bullets pretty much with in .5 grns,

Another trick is if you cant keep from over heating the mould is to cast with 2 moulds in tandem. giving them time to normalize between pours

[CoolHandMoss]

With the right temp on the pot fill the mould watch the sprue you will see it molten then solidify then a "frost" comes over it give it a 3-8 sec count and cut the sprue. Adjust your pots temp to your cadence. Wrinkles up tem 20-25* starting to frost lower 25* dont stop casting let it adjust as you go.

Thanks for your response. Question about this bit. Am I to understand that if the sprue is frosting over after it solidifies then the pour is likely too hot?

[Conditor22]

I cast everything but pure between 680-720° (pure -750°)

I preheat my molds on a hot plate to 400°

older books have higher loads

If the boolit is of the same weight but a different design that would explain some of the difference-- more bearing surface

Then once the mold gets good and hot I start seeing bad sprue cuts where it looks like the sprue plate kind of drags some lead out of the middle of the boolit and leaves a little divot in the base. ---You need to get into a rhythm casting, leave the pot temperature alone. Watch the lead puddle (sprue) and wait for it to change colors then cut it.

If the pot gets much cooler I get more prone to wrinkles. -- 720 is good, if you get wrinkles, add a little tin/pewter to the pot so you can cast at the lower temperature. The other the alloy temperature the more the boolit will shrink after you pour it. Yes, you can cast at 750-800° BUT you will get more boolit shrinkage and it will take a lot longer for the mold/sprue to cool enough to cut.

rounded edges on the bases of the boolits --- you let the sprue plate get too cold and the lead is hardening when it touches the sprue plate before it fills out the base--- get your rhythm down

My 2¢

[Conditor22]

Am I to understand that if the sprue is frosting over after it solidifies then the pour is likely too hot? -- if you mean change colors, that is what you are waiting for to cut the sprue, this is different from the frosty boolits

[Cherokee]

Hi Coolhandmoss - I always allow the sprue to cool to the frosty look before cutting the sprue and cast @ 725* with aluminum molds, mostly 5-6 cavity. Frosty sprue does not mean your metal is too hot. Lee doesn't develop it's own data, they generally just copy spec's from anther manual. I would stick with the Lyman manual for bullets of similar weight and shape, keeping in mind its the case volume below the base of the bullet that will significantly impact pressure/velocity. OAL does make a difference. Seems you have a good approach and questions. Keep plugging away.

[CoolHandMoss]

Am I to understand that if the sprue is frosting over after it solidifies then the pour is likely too hot? -- if you mean change colors, that is what you are waiting for to cut the sprue, this is different from the frosty boolits

Oh I see. He means if the boolits are frosting, not if the sprue is frosting. Thank you sir for all your help.

[ryanmattes]

I'm new to casting too, at least compared to most of the guys on this forum. I've only been casting about a year, and so far only for a handful of pistol calibers.

When figuring out where to start with a new load, here's my process and thinking:

For a given caliber, I'll get 2 or 3 molds, usually 2 cavity so they're cheaper (or watch the selling forum, good deals on there), to get a couple different bullet shapes. I usually have a target weight, but sometimes I'll get different weights. At any rate, I'll cast about 100 good slugs from each mold, sorting out the ones with defects and those that are more than .5 grains off of my media weight. My 125 grain 9mm actually end up 127.0 +/- 0.5 grains.

I'll usually do 3 sizes on each kind of slug, e.g. for 9mm I did .356, .357, and .358. Coated before sizing or lubed after sizing, depending on how I want to do it. I'll pick a middle of the road load in a common powder from the book, and load up 20 of each. So for 9mm I did 2 shapes in the same weight, by 3 sizes, so that's 120 rounds total.

I take those to the range, and set up 6 separate targets, one for each group. I'll load a single round, fire it, and then inspect the barrel. I'm looking for leading, unburnt powder, etc, just anything to give me an indication that something isn't behaving how I want it to behave, to decide if I should keep shooting them. If it's good (and it usually is) I'll load 3, shoot them, then check the barrel again. Usually by then you'll see leading if the size is too big. If it's good, I shoot the rest, and check the barrel again. All shots in the same target, carefully aimed, to test the groupings. I don't expect groupings to be fantastic, I'm just trying to watch out for flyers, keyholing, etc. Clean the barrel and repeat for the other 5 groups. It's important to start clean, so you can see any leading immediately.

Then I'll take those targets home and put them in my load book, and figure out which ones I like. With 9mm, both shapes showed keyholing at .356, one worse than the other, and both showed some degree of leading at .358. so now I know, .357 is my size. I also decided I like one shape better than the other.

Then I go and do a ladder of 3-5 different powder charges (same powder) in the preferred size and profile, to figure out where my pistol likes them. I'll test shoot those and find the load I like, and then I have a baseline to start playing with the variables one at a time. I found that it didn't change performance noticeably, but water dropping the 9mm made them slightly harder, which means less worry of dropping a round and deforming it so it's unusable, especially after it's coated, but more importantly it speeds up my casting process.

And if I ever get bored, I'll just go back to the other bullet profile and work up a load for that one. The main thing is, write down everything you do, keep your targets, collect data. As much data as you can, so you can reproduce it.



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[mehavey]

The sprue will always "frost over" when solidifying. So it's no indicator.
If the bullet drops out of the mold frosted, then you're probably running hot.

But here's what really matters: FROSTED BULLETS SHOOT PERFECTLY WELL.
(So unless the bullet is "finning" on you; or liquid lead is smearing onto the mould top when opening the sprue;
or the bullet is literally breaking in half when coming out of the mold....

...don't worry about it.)

[CoolHandMoss]

Ryanmattes: your process sounds completely reasonable. Thanks for letting me know what works for you. I will definitely use your process as a template for my own.

[CoolHandMoss]

Mehavey: that's good info. I was curious about the consequences of pouring too hot since hot pours tend to yeild nice boolits aside from the obvious consequences of excessive mold temperature, dirty sprue cuts and bullets that break! Thanks for your response.

[country gent]

Not to hot its just a second sign of the sprues cooling process. its happens as the spure is cooling and gives a little idea where the casting is at. Frost may not be the right word to describe it, why I put it in asterisks. Its like seeing mirage on a hot road. After the spur solidifies you see a second change in the color appearance flow across. I normally run 20-1 in the 700-720 temp range, but I also ladle cast from a 120 lb propane fired pot. Ladles have had spouts opened to .205 dia for a faster flow. I also run 2 different moulds in tandem to keep from overheating.

Am sorry for the mis wording causing confusion.

As I said above its hard to describe it, watch the sprues in good light and you should see it. I tend to lightly rock the mold while its cooling and you see the sprue solidify then this color change happens. If you watch for it its apparent.

[CoolHandMoss]

I appreciate your explanation. I am familiar with the frosting that the sprue undergoes. I have been waiting for this frost then generally waiting a 5 count before cutting the sprue to try to get a clean cut. I just misunderstood what one poster was saying about frosting. My original question resulted from waiting 5 seconds and more after the sprue frosted before cutting the sprue and still finding cavities in the boolit base. It sounds like I've been keeping the pour too hot and maybe letting the pour flow a little too slowly based on responses so far. It also sounds like I just need some real iron and brass molds!

[country gent]

Aluminum is a fine material fir moulds. Slow down you cadence a little, maybe try the 2 mould in tandem.
Preheat the moulds up close to temp. Foll the first one and set it down on a solid surface. fill the second set it down and and cut the sprue and drop bullets refill. repeat with second. Ether use 2 moulds the same or 2 moulds of very dissimilar appearance and size and or so they can be sorted easily.

Another thing is to keep a note book with what youve tried and how it worked makes a good reference when setting up the next time

[CoolHandMoss]

I imagine that if you are using the two mold method then you might end up needing the pour a little hotter than if using just one mold? Hotter pour, good fill out, cooler mold that cools the boolit a little faster and gives a better sprue cut?