sprue appearance

[soldierbilly1]

What does your sprue look like before you hit it with your mallet?

Is it thick on top? or is it thin?
the reason I ask is that I think I am running on the hot side. With a thin sprue this old man can give one whack on the sprue plate and the sprue is off and on its way to the sprue box!
With a thick one, it may take several whacks, which I feel is not good. when I look in the Lyman manual, all the photos it appears to be thick to me.

Am I running the mold too hot? time to get a temperature monitoring device?

the casts are a bit frosty but well done!

I'd like to hear from the crew. I haven't seen this mentioned before (?)
bill boy

[geargnasher]

Opinions vary on this subject, but I'll share my methods and you can do what you like.

I don't hit the sprue plate or use a mallet if I don't have to. I cut the sprue before it's so solid that the sprue plate has to be clubbed to death to get it open unless I'm using an alloy that's close to eutectic (like good, straight linotype) or pure lead, since neither has much of a "mush" phase and tends to go from molten to solid all at once. My method with wheel-weight, hardball, etc. that has a long "mush" phase is to cut the sprue with a gloved thumb before it sets up solid, but when it is "set" enough not to smear lead on the top of the blocks. There is usually about a half-second to second window when you can cut the sprue by hand and not smear lead on the blocks, you'll just have to experiment and see. Watching the sprue "flash" through its different sheens is your clue as to what it's doing and when to cut.

Use Bullplate sprue plate lube or similar substitute to create a microscopic film on top of the blocks and underside of the sprue plate and prevent the smearing of lead.

If you cut the sprue at the right time, it won't matter the THICKNESS of your sprue, the part you cut remains the same size. Altering the thickness and size of the sprue puddle is how I control sprue plate temperature. Sprue plate temperature has a lot to do with how well the bases of the boolits fill out, and if that sprue plate isn't hot enough, you can't cut the sprue fast enough before it sets up so solid you have to whack it. I also use a mould oven to preheat my moulds so even the first pour can be cut by hand.

I too like my moulds hot enough to produce boolits with wheel-weight-ish alloy that have a light, even, satin frost when cooled, and cutting the sprue early and by hand, then pausing for two seconds to look at the boolit bases and give them a chance to finish freezing before opening the blocks gives me the results I'm happy with. You will probably find that doing this will leave little "goat ****" puckers in the center of the boolit bases, and as long as they are consistent (they will be if your pace and timing are consistent) they don't hurt a thing. In fact, having puckers rather than teats is better for seating gas checks squarely.

Gear

[DLCTEX]

If you cut when the sprue flashes dull you can cut it as I do, just a push with a gloved thumb. You may need to lube the sprue plate with Bullplate or maybe synthetic 2 cycle oil to prevent smearing. I don't like hitting my moulds with anything. Watch the sprue and it will change from a wet look to a dull finish, cut then or give it another second or two if the boolit bases look wet when you open the plate. Light frost doesn't hurt a thing.
Gear said it better (as usual) while I was entering a response.

[casterofboolits]

On my Lyman four cavity moulds I like a really thick sprue, at least a 1/4" thick. Mine cut just as easy as a thin one. One tap with my Sears 6oz plastic tipped hammar does the job.

I run at least two four cavity moulds at a time and after I pour the second one the first has solidified and is a matt gray color.

YMMV

[runfiverun]

i don't even wait for the sprue to change color..
i open with a gloved hand and slip the sprue right back into the pot.
you will see it suck the lead down and have a slightly slushy spot under the skin, as soon as that stops the sprue plate is opened.
i only hit the sprue for about the two first pours then i open by hand after that.
the rest of the time the sprue is still shiney silver.
it's about a 4 count after pouring.

[ku4hx]

I generally wait a couple of seconds after the last dollop solidifies. Molds tend to be very individualistic with some requiring a larger puddle than others. One of my Lee six cavity 45 molds prefers I fill her from the hole nearest the handle first and then move forward; others it doesn't seem to matter which direction I fill.

I try and minimize whacking but on a couple of my older Lyman molds I have resorted to using a "cheater" bar: a short piece of galvanized pipe with a copper tube sleeve in the business end.

[soldierbilly1]

Super responses! thanks to the Gearman et al!

billy boy
PS this ain't written in books!

[462]

I do as Gear and DLCTEX do -- flash, suck, and cut. (Watch, that'll get me in trouble.)

Yesterday, I was casting with a Lyman four-cavity 452473 that had been pre-heated in a mould oven. The first pour required a mallet tap to cut the sprue, which indicated that the mould wasn't hot enough. Placed it back in the oven for a while, and the next pour's sprue was cut with a gloved thumb.

Later in the session, the boolits started to take on a glossy appearance, rather than satin. Pouring a few larger sprues quickley got the mould back up to its optimum casting temperature.

Edit to add:
Billy Boy, most of how we do what we do isn't written in books. However, you'll find a lot of it written here. The rest you'll learn through experimentation.

[Suo Gan]

Generally when the surface dulls its time to cut. If you get lead smears wait a few seconds longer. Bull Plate is good stuff, but not a cure all. Each mold type and really each and every mold is going to need different things. If you are using a stick, there is no need to "beat them to death" as is so commonly stated. If you are beating them to death you are doing it wrong plain and simple. Its about timing an getting into the groove with the equipment. It usually does not take long to dial it in. I started with aluminum molds and went to iron and brass and am back to aluminum as my preferred bullet mold material. Each size block, sprue material, sprue thickness, sprue plate thickness, mold metal, cavity size, alloy temp, mold temp, alloy type etc. is constantly in flux, once you get one mold pretty much dialed in, you start with another, or put it down for a month and forget. The job of the caster is really to see and understand what is going on to bring down the number of boolits with voids, rounded corners, out of roundness, etc. It really is an experience thing and is hard to generalize it down into a little box. The best advice I can give is just to cut it when the sprue frosts over, and if you are getting smearing just cut it a few seconds later until it gets dialed in. Consistency is king and unfortunately that is a hard thing to master. I am just happy that I figured out that even the ugly boolits shoot pretty darn good for 99% of my shooting needs.

I have been at this several years now and am still learning every time I cast. I don't know if that means I am dumb or smart, but it is humbling anyway you look at it!

Good luck and keep on casting!

[stubshaft]

It depend on the mold/bullet I'm casting. In most cases I wait until the sprue just freezes and in others especially the 22 molds I just count to three and cut the sprue while the surface is still melted, I usually pour a heavy sprue and it weighs more than some of the 22 boolits I cast but the base is already frozen.

[1Shirt]

Gears analysis is pretty well spot on. When I am using a single or double cavs, I cast with two molds at the same time. When you have a sequence built up, it can go pretty fast, and maybe 3-5 seconds between molds if you work at it. Can keep it up for mayby 25-30 mins before I need a break, but with two double cavs, that is a lot of blts. I cast as hot as the furnace will go, and like a bit of frost. Just my opinion.
1Shirt!:coffee:

[geargnasher]

I'd like to further comment on something Stubshaft mentioned, cutting the sprue while it's still molten with tiny boolits. I don't cast .22s, but I cast a lot lf 6.5MM boolits and have found that the tiny amount of heat the boolits impart to the blocks needs to be compensated for by a blistering casting pace. The lead in the cavities sets up almost instantly, but the sprue takes a few seconds longer almost all the time with just about any mould at casting temperature. So I pour and cut almost immediately, the sprue crumbles when it hits the sprue pile because it's still semi-molten, but the boolit bases don't smear (especially if using Bullplate) because the mould blocks are relatively cool.

Like Suo Gan said, every mould is different. I'll add that every casting session is different depending on the weather and particular flavor of alloy you're using. I used to keep a mould log with notes on each mould and alloy regarding specific timing (actually timed each operation), alloy temp, ambient temp, and special notes on technique, but after a few years I began to see a pattern that worked for determining ideal parameters for just about any mould and casting situation with the exception of pure lead and special, eutectic alloys, so I abandoned the casting logbook:

>> Use a thermometer to determine the temperature of the "mush" phase of the alloy in the pot. This temperature will be constant from the "brown sugar" consistency to the "Cream-O'-Wheat" consistency. The instant the last grain of alloy melts in the temperature will again begin to rise as the phase change is complete from solid to liquid. I note the temperature and add 100 degrees F to it, that's going to be my alloy temperature for that session. I set my PID controller or mark my thermometer face with a sharpie and maintain the alloy at that temperature.

>> Next (well, actually first) I preheat my mould in a steel box "oven" on an open-coil hot plate until it's about 400 degrees or so. It takes about 20 minutes to get thoroughly soaked, so I set that up while I'm waiting for my alloy to melt.

>> I put on a little sprue plate lube, lube the alignment points of the mould, test and adjust the pour stream from the spout (if using the bottom-pour furnace), and fill the cavities, making a generous sprue puddle. Judging by the time it takes for the sprue to set I can tell how hot the mould is and if I need to preheat some more or let it cool for a few seconds (depends). I keep my sprue plate whacker handy in case the sprue plate is too cold and freezes before I can cut it by hand. Usually by the third pour I'm casting keepers, and I watch the second hand on the clock and the "finish" on the boolits as they cool to determine how many pours per minute this particular session takes to keep in the "Zone" of temperature that makes good boolits. After a while I memorize the rhythm and quit worrying about he clock.

>> There are variations on this theme, sometimes a hollow point mould will like the temperature at 125 or more above full-liquidus, sometimes a large-cavity steel mould will want only 75. Sometimes I use a propane torch and holder to keep the HP spud hot, but usually not.

>> When water-quenching, I throw every tenth or twentieth boolit on a towel and check the surface finish to insure the mould is at a steady temperature, the consistency of the temp the boolit is when it hits the water is critical to consistent hardening.

>> Pure lead is a "Katy bar the door" endeavor, I usually run the pot at 800 or more degrees unless I'm adding tin, in which case I never go over 750. Pure lead loves a ladle and a little head pressure from a contact pour.

Little adjustments to the pace are automatic after a while once you know the "signs" of sprue sheen, boolit sheen, etc. and develop a smooth, consistent rhythm to your casting routine that can be tweaked for any conditions.

Gear

[runfiverun]

gear if you don't quit writing down what i'm doing..........I swear.......
i'll put curtains on the shop windows..:lol:
it took me a while to figure out that if i tried doing things the same everytime i would have better results.

[MBTcustom]

I am another one that uses a glove.
I pour with a ladle over the pot. I pour lead in and let it run over the front of the mold until I am certain that the cavities are filled, then I roll the mold back while still pouring and try to get a puddle. I watch the lead and wait until the sprue frosts over then I count to three and cut it. That just seems to work with every mold I own so far. Its right there where the lead is still soft enough to slide the plate over with finger pressure but not so soft that it "plucks" a divot out of the base of the boolit. When I open the mold, I expect the boolits to just drop out but if they dont, I just nudge them out with my gloved thumb. I will never hit a mold with anything ever again, even to get the boolits to drop. It just makes sense.

[1bluehorse]

I use the wooden whack-o-matic....

[fredj338]

IMO, thicker the spru the better. The amount you are cutting is identical. Cut right as it solidifies & it doesn't take much effort.

[Moonie]

When I first start a casting session I will pour a large spru until the spru plate gets to the temp that it is easy to cut the spru by hand (gloved hand). Then I'll make the spru smaller to control the temp but large enough to keep the bases well filled out.

[soldierbilly1]

OK, I learned a lot in this thread alone.
I am now utilizing a gloved hand to open the sprue plate. Works really nice once the sprue plate is hot enough on my Lyman 4 banger. As you guys stated, the bases really don't fill out nicely until the sprue plate is hot. I am certainly more attuned to the phase change on the plate now as well.
I just added the RCBS casting thermometer to Mr. L. Potterfield's Wish list!
thanks to all for the tips!

billy boy

[runfiverun]

there's cheaper places to get a thermometer or a better one for the same money keep looking.

[Lizard333]

I also use the wooden mallet but it doesn't take much. I learned early on that a harsh hand with the mallet could bend the sprue plate!! Once the mold is up to temp, I tap the plate after the sprue has hardened. Having the wooden mallet in my hands makes for easy removal of the boolets should they stick. A lite tap on the hinge of the handles does the trick.

I prefer a thicker sprue, as it keeps the sprue plate at a better casting temp. This helps as I often cast with two molds at once. Unless I am using a four cavity or six cavity, then I only cast with one mold.

The thing is, is your going to have to do works the best for YOU and your mold. What works for some won't work for others. Give it some time. The more you cast the better you will get!! Good luck!! :)

[prs]

I have to admit to not wearing gloves while casting; do as I say, wear gloves, not as I do. For my moulds with the mallet strike type of spru cutter, I quickly found that the clumbsy mallet was not needed. I found a small hickory tack hammer handle in the scrap bucket. I used the band saw to cut a "V' notch in its end and use that to push the spru plate open. Its small enough to fit in my hand and still allow me to operate the mould handles quite well.

prs

[soldierbilly1]

RunFiveRun:
thanks, I'll look around.

bill boy