I have a new question about the joys of Aluminum moulds. Instead of using a wet rag to cool the sprue plate, would a Heat sink removed from a VFD or such not work well. Anyone tried it?
Colby
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I have a new question about the joys of Aluminum moulds. Instead of using a wet rag to cool the sprue plate, would a Heat sink removed from a VFD or such not work well. Anyone tried it?
Colby
Last edited by osteodoc08; 12-28-2019 at 10:01 AM. Reason: Edited by Mods
http://castboolits.gunloads.com/arch.../t-107964.html
Search feature is very handy. This is from the archives so yes, it was tried.
There's no reason to make it complicated.... I usually use the damp rag method, but I have also used a small container of water and just touch the bottom of the filled mould to the water every third cast or so. I know everybody freaks out about having water around molten lead, but I keep it two feet from the pot and allow the water to sizzle off the mould before another cast. Works great, and I've never had a bad experience or warped mould doing it this way.
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I place a 6"x8" piece of 3/4" aluminum tool plate next to my bottom-pour pot and use that as a heat sink, holding the mold on the plate until the sprue frosts. Never had an overheating problem with any mold, aluminum or iron.
Bill
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I'm with you on that aluminum plate, the mass of it must make it like a heat sponge. I use the bottom aluminum plate on my Lee Drip-O-matic.Originally Posted by Kraschenbirn
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I cast in tandum or just slow down and inspect bullets a few minutes if I'm running hot.
Thanks for the tip on the heat sink. I might give that a try.
When the mold heats up too much I stop, leave the mold on the rim of my Lee bottom Dripper and take a while to put sprew back in the pot. I spend a little time culling bullets and then back to casting. I figure the melted lead will cool a bit when I put sprew and errant boolits in, however it heats up quick, I usually run my pot at least half full.
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I use a lee magnum melter. When letting alloy run over the sprue and back into the pot, I've found I get splashes if I get less than half full. Pouring that way I get the best fillout using wheel weight alloy with minimum tin added. I run the mould hotter that way.
Hey chaos
Myself and several of my buddies shoot Lawnsteel exclusively with cast. We have been using a long fin computer power supply heat sink with an integral fan for several years now. Powered by a cel phone charger that supplies 6v modified ac current. Photos and detailed documentary are on the Cast Bullet Assoc site under the thread title "cooling the mould". So many other methods are used by casters that "kinda" work, but most do not produce zero variation results. Some of the procedures are actually detrimental to producing superior quality projectiles. Need/want more info? Just ask.
Roy
Shoot often, Shoot well.
If your mold gets to hot try using more molds in rotation ,two or three work for me .gives time for molds to cool without having to slow down.I cast 357/45-70/308 at the same time can usually cast a few hundred in an hour.
+1. I do the same thing these days
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Yep the slab of metal method is way better than we rag. The rag will dry quickly and is more complicated and touchy by far. Just find something metal and flat (I use steel plate) it works brilliantly.
I was having some smearing, galling, and scoring problems. In looking for some answers I came across BruceB’s posts. His posts on speed casting and sprue plate cooling helped me a lot. I like how he set up and how he worked his molds. His method of cooling sprue plates was dead simple.
I was getting lead smearing on my sprue plates and scoring/galling on the tops of my aluminum molds. I’ve done three things to stop this.
1. I cool the sprue plate per the BruceB method. Wet rag quench.
2. I stoned the bottom of all my sprue plates.
3. I started lubing my molds with two stroke oil.
I want to cast good and fast. I don’t want my mold to cool down. Aluminum molds run better when hot. I do however, want my sprue and sprue plate to cool down fast. A quick three count touch to a wet rag does what I need.
JM
Heck yeah. Right up my alley
I would go with a combination of using 2 molds and setting them on a heat sinc. I use a piece of 1/2 X 6" steel bar about 6ft long for a landing zone when I'm smelting scrap. It eventually gets so hot that you can't touch it but by then my 400# pot is getting empty.
I usually use three 2- cavity moulds in tandem running the Lee pot 3/4 max temp resting them on my 6" thick cedar casting bench between casts. I never use a pid or wet rag. Cadence and consistency is key. For me and my stuff. Yours may differ. If just casting one style boolit (rare) I use the aluminum plate on the furnace for heat sink purposes.
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Those people are...unnecessarily cautious. I've cast with an open pot under a deck in the rain many
times, with droplets leaking down through the slats and making a hiss when they hit the surface but nothing more.
The way you run into trouble is when when the slightest bit of moisture gets under the surface of the melt than rapidly expands.
You'll get a pop and a splash of molten alloy if you drop and ingot straight into the pot without cautiously allowing it to warm up first, but an odd splash of water onto the pot certainly won't do it.
You claim of "zero variation" results is amusing to me, but perhaps I am underestimating your devotion to consistency.
I then presume you take a mold, use it once, then set it on the cooler for a certain interval before using it again?
What sort of relative standard deviations in mass do you achieve?
Actually, no, I partially take back what I said above, "zero variation" is still an absurdly lofty claim. But I am still quite interested in the way you do things.
Ok Peregrine
Rather than respond to your cynicism, I will address your interest. The most obvious answer would be for you to research the earlier mentioned thread on CBA.
Proper maintenance of all variables is necessary when "zero variation" is to be achieved. Simple consistent cooling of the mould is the topic at hand. My particular casting setup involves a PID controlled furnace, double insulated reservoir, single cavity mould, consistent alloy properties, dedicated casting area, +54 years of casting experience, extensive recorded data and the finest whiskey on this planet. An infrared analysis shows heat transfer and flow in dissimilar metals fluctuate wildly with voids introduced into the host material. Casting is the introduction of a dissimilar metal into a host material with voids. A mould at a consistent receiving temperature, charged with molten alloy at a consistent temperature, with heat removed at a consistent rate and in a manner to yield uniform heat signature, will yield consistency. Removing heat from the bottom of a mould is the most desirable direction as it has the greater host mass. Water will eventually heat and have different cooling properties. Same is true with most metallic forms of heat sink. Ambient air cooling is very effective when timed properly and time is of little value. Just a nugget for those paying attention, a large coffee can bottom up, makes an efficient heat sink and sheds heat at an appropriate rate. In my casting, temperatures are monitored at; pot spout, reservoir center, mould exterior, mould interior, heat sink receiving surface and area ambient. The dynamics of high/low temperature liquid lead, shows measurable differences, ie; weight/size. Maintaining consistent temperatures at critical points will stabilize standard deviations and minimize average deviations. Commonly available electronic scales will show "zero variation" regularly, a higher accuracy beam balance scale is needed to show actual weight differences. In the hands of a Master tool and die machinist, a Sterret micrometer shows "zero variation" from random selection of test examples. It is now much less common for me to extend the effort required to produce what others refer to commonly as "magic bullets". Not only can I do so, my students do so on a regular basis. Heck, I'll wager you could do so, instructed properly.
Last Tuesday I had the pleasure of some mild impromptu shooting competition. Four of the five present were past Florida sunshine state shooting champions. All shoot their own cast projectiles, handload and won their championships with such. To say they are good shots is a gross understatement. Turkey silhouette targets are commonly taken with head shots at distances greater than 70yds using a Ruger Blackhawk with iron sights only. This is not considered a difficult task from those attending. "Good enough" and "minute of milk jug" ammo is not what they use. When I first met each of them, they had never cast a projectile or loaded any ammunition. Now they thrill at beating the teacher. Little do they realize, the pleasure is mine.
Learn and excel.
Roy
Shoot often, Shoot well.
I don't have a scientific background but I would think that "zero variation" would be impossible to achieve. But I'm another that strives for it. I cull bullets that my casting buddies would keep and they even tell me that I'm too picky. Their argument is "its good enough". They shoot at a human size target at 7 yards with a "10" ring bigger than an entire 50 yard Bullseye target! But by paying attention to detail, maintaining proper temps and establishing a cadence the weight differences of my cast bullets rival the weight differences that you see with Berger and Sierra jacketed bullets.
But just for curiosity, gunarea, what do you consider the finest whisky on this planet to be?
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