Folks, if you have not used Lee molds or aluminum molds before and especially the big 6 cavity models; thenyou are in for a treat if you just let yourself be flexible and break away form some of your iron mold habbits for a spell. The 6 cavity molds are very high quality equipment, but are fragile (as are all mlds) and require special lube and care. Be prepared to go through a lot of lead fast!
Slims advice about casting with the Lee 6 cavity PRS molds.
Read the factory instructions! Follow all precautions for lead and heat protection!
1. Clean the mold blocks and inspect closely for any burrs on the block mating surfaces or cavities (you probably won't find any). I clean my blocks with detergent and water, rinsing well, and then the cavities with 90% isopropyl alcohol and cotton swabs.
2. Carefully operate the spru plate to see if its going to scrape or gall the top surface of the molds. If any scraping is noted, then use a fine stone to slightly round the offending edge of the plate -- usually the heal of the spru plate is the only area that rubs.
3. I like to have the spru cutter pivot screw just tight enough to keep the spru plate from having play in it -- it should swing open under its own weight, or nearly so. This allows trapped air to escape and make nice bullets EZ. If that screw tends to move (back out) in use, I use blue Loctite to provide some resistance to that.
4. With the mold pre-heated, lube the mold at its guide pins, handle hinge, spru cutter pivot, and spru cutter lock stud. A very small bit at the heal of that spru cutter plate also is prudent -- it will smear out onto the top of the mold blocks a bit and help protect that vulnerable area. Use NRA formula bullet lube only (50%beeswax + 50% allox). Get the lube only on the right spots and not on the half faces or cavities. If you get some lube in a cavity, then you must scrub again, no harm, just time and effort. Use very little lube. I use a wood match stem or tooth pick is a lube applicator. Re-lube very sparingly after every 10 minutes of use and just before you quit. This will make your mold last until you drop it! (DON'T DROP aluminum molds, or any mold for that matter!).
5. When I start, I bring the mold up to temp by resting it on the pot as the alloy heats. I let the alloy get up to temp and hold it there a few thermostat cycles, then flux, stir, skim, and cover with granulated floor dry/oil dry clay based stuff. Once the mold is hot, I smoke the cavities with a burning wood match stem and then, holding it closed with modest pressure, I dip the heel (heel is closest to handles -- toe is away from handles) of the mold into the melt for about 30 seconds. Then I cast. If its hot enough I notice little to almost NO resistance of the spru cutter going through all 6 spru and the first poured cavity will still be molten as the last is filled. Colder than that, recycle the bullets and refill the mold and rest the mold on the pot side to further heat it as the bullets cure. Dont keep the bullets until the mold is hot and working properly.
6. Bottom casting is the only way to go with these big 6 cavity jobs. Try both directions (pushing and pulling the mold through the fill stage), but I do better filling the cavity closest to me first and then working toward the far or toe end - pull technique. I pause the flow between cavities for just a "nano-second", but the sprus still run together to make a strip of spru. If you quiver or vibrate the mold as you move between spru holes (you will figure it out) it helps settle the molten lead or purge any air trapped within the cavities. Your pot needs enough capacity and enough wattage to keep up. I do well with 20# 800 watt pots.
7. Since I get my best bullets when the first filled cavity's spru is still molten as I finish the last cavitys pour, hot mold and quick hands are welcome; but pour rate should not be too fast or air will be trapped in the cavity. Keep just modest handle closure pressure on the handles during the whole pour and until the spus begin to freeze (few seconds). If the first cavity is freezing before the last is filled, then I rest the mold on plywood between fills or better yet on the edge of the pot - this allows heat to build. If they are all molten and nice and then turning out evenly frosty, I rest the mold on aluminum angle scrap or other metal scrap as a heat sink to more quickly freeze. With a single mold, a good quick pace is a fill every 15 seconds or so; with two molds the turn around per mold is slower, but the operator pace is faster. You can work slower to build heat or faster if you can and your pot can keep the heat up.
8. I drop spru waste back onto the clay chips floating on the melt and add alloy as it is depleted. Take great care not to splash molten alloy. I re-flux right through the clay granules and don't worry about any dross as it is trapped in the clay granules. If using two pots and two molds, I run both molds on one pot until that one is half depleted, then reload that pot and begin using the other. Such rotation keeps you running smoothly without cold alloy wrinkles or flaws.
9. Drop the PRS bullets on a very soft terry cloth pad, let them cool slowly so they will be soft. Don't harden or quench.
10. WW alloy (wheel weights) is ideal. I boost the tin by 1% when I render the weights into muffin ingots, but maybe that is a waste of tin. I don't actually size my PRS bullets since they drop right at .454". I use the .454" die in my 450 Lyman luber and its a glove fit. If the bullet bases are smeared out a bit (opening spru plate too soon), then the size die will correct that. I reject all imperfect bullets since they are so fast to cast correctly. There is no sense in accepting imperfections and it is critical to have perfect bases that will seal with the Holy Black Powder. I do like uniformly frosted bullets.
11. When finished, lube the mold and then wipe it clean with a cloth while it is still hot.
12. 50# of alloy will yield 1400 bullets in about an hour once ya get the hang of it --- given a preheated pot and mold to begin. Two molds in tandem may give you 2000 in that same hour --- but don't race or your back will hurt and you will make mistakes. Two molds almost certainly will require two 20# pots to keep up with them. Use eye and skin protection. No mallet required or desired.
Regards;
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