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This is a new one for me and yes, I checked FAQ. Just picked up a Saeco/Redding two cavity mould (I have several) and the sprue puddle sticks in the plate. Now I've had a lot of moulds where the bullets didn't release very easy but I've never had to push the sprue out from the bottom of the plate before. Any ideas as to the cause? Gp
Check for burrs and or nicks in the pour hole, it also may need to be sharpened.
You can do that with a slow turning countersink in a hand drill or drill press or
on a flat surface and some 320 grit or finer sand paper sharpen the bottom by
using a figure 8 motion.
zinc in the mix will also cause sticking in the sprue plate, even though you may still cast decent bullets. Try anothe mold and see if that sticks as well.
If your sprue plate cuts a clean base, maybe it just needs a little polishing on the countersunk portion or you could smoke it before the session.
Never had them stick like that.
+1 on smoothing/polishing the hole and bottom of the plate
Thanks Guys for the reply's. Well, there were no noticeable burrs in the sprue holes checking with a Q-tip and alloy works fine in other moulds. I'm thinking all it needs is sharpening. I, for one don't mind a LITTLE zinc in the alloy as it works well to harden the alloy and in minor amounts doesn't cause me a problem. I'll sharpen as mentioned above and believe that will most likely take care of it. Just took me by surprise as I'd never had this happen with ANY other mould. Thanks Gp
About the only problem mold I had with the puddle sticking to the plate was a Redding/Saeco mold. It was several years ago when they were trying to figure out whether to make the sprue holes large or small. I ended up polishing a taper in from the top of the plate and then lap the bottom so there was nothing to allow the sprue puddle to grab. I thought perhaps the cone was not quite drilled deep enough and the parallel section in the plate was a bit too long. Something to look for anyway.
I had a Lyman mold that gave me fits one time - it was a used on that I had picked up cheap. It dropped boolits like butter but the sprue held on like it was welded. I finally removed the sprue plate, gently stoned the bottom on an oil stone and then polished the sprue hole taper and top of the plate - that did the trick on that one. YMMV
Not dealing with sprues - but larger base pins. I have a number of molds for larger hollow base boolits - 58 caliber minie balls of different designs as well as other calibers. One trick I learned probably 50 years ago was while you would normally give the base pin a twist - my process is pour, cut sprue, twist base pin and pull and then drop boolit - it doesn't always work that way. I've had the minies/boolits stick to the sprue pin like glue. Once the mold and base pin are up to temperature, I keep a bock of pure beeswax on the bench and I just gently touch the area of the base pin which forms the hollow base to the beeswax - no more sticking. I might have to repeat it every 100 pours or so but it does the trick. I have also donate same thing when a sprue plate on a steel mold starts to tighten up while casting - just tock the beeswax to the top of the blocks, move the sprue plate back and forth and keep moving. It only takes a touch - don't know if it would work on a sticky sprue but you might try it on top of the sprue plate - just a sight touch and none will go in to the cavity.
Dusty, Billy: Thanks for chiming in. I had Never had this happen before with 30+ moulds I'll stone the plate and polish the sprue holes. I can't see it being anything else. Something new regularly around here. LOL Gp
I have this happen a lot , casting fast and hot seems to encourage it. I keep a wad of 0000 steel wool and a old piece of rough cloth that had been used to wipe up some old motor oil (synthetic 2-stroke oil would be fine) on hand. When the holes start sticking , a quick clean with steel wool , work fast the wool gets hot, then a wipe of the rough oil impregnated rag gets it back in shape.
Sometimes if you catch it quickly the rough oil cloth will clean it.....other times the wool has to be used.
Gary
I stoned the under side of the plate and did a quick spin in the sprue holes from the top side with one of those tapered drill bits you see at Harbor Freight. Polished the sprue holes with steel wool and all is right in the casting world again. Gp