Puzzling Lee mould issue

I went to cast up some .490" and .495" balls earlier this week. Now, I don't have a .50 cal. ml rifle but do have this funny itch telling me one might be coming my way fairly soon. :wink: Ennyhow, I have had a .495" double cavity Lee mould for many years and can't remember the last time I used it. The .490" double cavity Lee I purchased recently. When I started casting I noticed many of my pours did not fill out the cavity. :hmm: Puzzling, not the kind of problem I recall ever experiencing in the past. I finally just took both moulds to the drill press and opened up the pour hole 1/64". Problem solved. But still a puzzlement as I'm sure my other Lee moulds have the same size pour hole as this .490".

My Lee molds have filled out well. But I’ve had issues with a custom mold and did as you, which helped, but didn’t quite fix the fill issues.

My only guess is that because of the size of a double cavity mold, it may be possible that you just didn't have it up to temperature. I know that you have cast a million balls in your day and that my guess is probably not right but it is the only thing I can come up with given the facts as you have presented them. :idunno:

Makes me wonder if your lead temp is lower now than in the past.

You were ladle pouring weren't you?

Would like to have seen pictures, but I assume these were knew molds?

I agree that temperature was the probably the real problem.

Colorado Clyde said:

You were ladle pouring weren't you?

Would like to have seen pictures, but I assume these were knew molds?

I agree that temperature was the probably the real problem.

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.490 was new, the .495 very old but long unused. I'm guessing temp also.

I would suggest too low of temperature for either the lead or the mold itself was too cool and a mold that has not been candled. Candling molds is something most folks either don't know about or simply don't do. It really helps the lead to flow and fully fill out the mold's cavity.

Lee molds are excellent but are very temp fussy.

There is a cadence to casting.

I have found a 21 second count after pouring and before rapping the gate keeps the mold warm enough and allows the ball time to cool before dropping on a towel as my optimal routine.

(1)Moulds won't cast their best bullets until there is some oxidation in the cavities. It doesn't matter what material they are made of.

(2)If the mould isn't sufficiently vented, it won't fill out consistently. You're pouring metal in, so air needs to escape. This can be forced by bottom pouring with enough head pressure or by pressure casting with a ladle. Enhancing vent lines allows the air to escape more quickly. Enlarging the sprue hole allows the metal to flow in more quickly. If the spout isn't mated tightly to the sprue hole, it also allows air to escape.

(3) If the poured metal isn't hot enough, its not going to fill out properly.

excess650 said:

(2)If the mould isn't sufficiently vented, it won't fill out consistently. You're pouring metal in, so air needs to escape. This can be forced by bottom pouring with enough head pressure or by pressure casting with a ladle. Enhancing vent lines allows the air to escape more quickly. Enlarging the sprue hole allows the metal to flow in more quickly. If the spout isn't mated tightly to the sprue hole, it also allows air to escape.

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A couple of worthwhile adds to your list, especially for large caliber balls:

Canting the mold a little to start the pour causes a "swirl" rather than splash as it fills, much like canting a beer mug to start a pour and control head. Off-center positioning of the lead stream in the sprue hole helps, too. In my experience those precautions are a big help at 58 caliber, almost mandatory on larger.

NorthFork said:

I would suggest too low of temperature for either the lead or the mold itself was too cool and a mold that has not been candled. Candling molds is something most folks either don't know about or simply don't do. It really helps the lead to flow and fully fill out the mold's cavity.

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Over the years I have candled, not candled with both Lee and Lymans. Other times (this one) I spray with Midway Arms 'Drop Out' mould release. The non-fillers were not wrinkled which is what puzzled me. Not enough heat almost always creates wrinkled balls.

I'm kinda in the poor venting camp if you are sure of the temperature being ok.

The drop out is good stuff but it will slightly reduce the size of the ball. That's not a bad thing but good to know.

I agree that the spray on stuff will reduce the diameter slightly, but the soot from the cheapest paraffin wax candle does not in my experience.

Maybe some oil ran don into the cavity. Try a good cleaning. The way I start out is to run the pot up hotter than needed. That gets the mould hot enough quicker. Then I gradually lower the temp until I get it where it needs to be.

Yes Mooman is correct. I always use either brakekleen or carb cleaner to hose the cavity out after storage. I then re-candle the mold if need be. I use a drop of bar oil on the mold hinge and a drop of beeswax on the sprue cutter pivot. Then heat mold up on hotplate or rest mold on top of pot while lead or alloy is melting. Mold needs to be hot before pouring for best results. Oil or other contamination in the cavity will drive you batty if you try to cast balls without cleaning it out first.

Rifleman1776 said:

The non-fillers were not wrinkled which is what puzzled me. Not enough heat almost always creates wrinkled balls.

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If the lead and mold are both too cold, the sprue hole can solidify before the mold has been filled.

Especially when ladle pouring.

Mooman76 said:

The way I start out is to run the pot up hotter than needed. That gets the mould hot enough quicker. Then I gradually lower the temp until I get it where it needs to be.

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That's the way I do it too.... :thumbsup:

Over the years I have occasionally modified the opening in the sprue plate of a few of my molds, Lee & Lyman, and even enlarged the opening on one of my ladles with good results. While that may not be the issue here I just want to point out that it is easy to do and replacement sprue plates are available from Lee for about $2 to restore the mold to its original configuration. Their mold parts are cheap enough that I bought some of their small parts to have on hand when I had to order some parts from them. Their customer service is first class too.

NorthFork said:

I agree that the spray on stuff will reduce the diameter slightly, but the soot from the cheapest paraffin wax candle does not in my experience.

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The soot from a butane fire starter works exceptionally well too, I keep one on my casting table exclusively for Lee molds...