Good vs Bad Sprue Shooting Test: Lee Mold

[Spikebuck]

I don't consider myself a master ball molder, but have several Lyman Steel molds and have had good success with them. I suppose I've run a few thousand ball through those molds.

Recently, I bought a Lee Aluminum mold in .575 for my recently built .58 Flint Hawken. I have to admit to having a heck of a time trying to get good ball with this mold. First, the lead kept bridging across the opening to the cavity. I finally ran the lead very hot...1000 degrees. This stopped the bridging and I was able to get several hundred ball done.

From a size and weight perspective they were pretty good. They measured .5745 + or - .0005. All but 23 of them weighed between 282 and 285 grs with the vast majority being 284 + or - 0.5 grs. I'm happy with these results.

HOWEVER, a good portion of the ball had defects around the sprue. Pictured below are two examples of the defect...also pictured are two good ones.

Since the weights and measurements were pretty good, I decided to do a 5-shot group with both types to see what happened. Pictures below are the results. Net, at 75 metres with the "good" balls a 2.25" group (measured center-to-center across the balls furthest apart. The "bad" balls had a 5.50 inch group. I swabbed the same between shots. There were no material delays in ignition or anything that would have caused me to flinch on any of these, so I think they are legitimate groups. Bench rested.

I really didn't think that this defect at the sprue would have this big of an impact, but clearly these ball need to go right back into the pot.

For those of you using Lee molds, have you experienced anything like this...the bridging issue, problems getting the cavity to fill properly unless you're running the lead very hot, etc.? I tried to keep the mold hot by holding it right on top of the pot while dipping, but clearly I was doing something wrong with this mold that I've not had any issue with while using my Lyman steel molds.

I also have to go back to some load development as the ToTW hand cast ball I used to work up my load turned out to be oversized by several thousandths...some even being bore sized! No wonder I was cutting patches, nearly bruising my hand on the short-starter, etc. Some poor quality control there. I'm going to bump my patch thickness a bit to "re-tighten" the load a bit and see if I can't get the "good ball" group shrunk down a bit. Need to tap that front sight over a bit too! :grin:

 

[tenngun]

I have run ball since the 70s and in general like lee molds. I do end up returning 1/3 of the balls to the pot, sometimes 1/2. .50 and less mold easier then above, my highest fail rates are the .62s. But even at worse your bad shots would be dead deer.

 

[swathdiver]

Goodness, most of the round balls i cast come out like the ones in the top photo, doesn't matter which mold (size) neither. Hmm....

 

[George]

I've found that if I knock the sprue cutter over too quickly it can tear chunks out around the sprue because the lead is still not totally solidified. If I slow down, wait a few seconds after filling the mold that never happens, it cuts instead of tearing.

Spence

 

[longcruise]

Those defects could be caused by several things. One would be low lead temp (maybe your thermometer is off). Another is explained by Spence regarding rushing the sprue plate (the hotter you run the more critical that is).

You could be experiencing a failure to completely fill the mold. Two things can be done to help with that;

First, you can leave a good sized puddle of molten lead on the top of the sprue and watch for it to dimple, which indicates that the cooling lead in the mold has sucked more lead in to fill the mold.

Second thing you can do if you have the right ladle is to hold the mold flat while pouring and quickly place the pour spout tightly onto the sprue hole to pour (clear as mud, eh?). That forces the cavity full. When you use that method it's important to squeeze the handles tightly together because forcing the lead into the mold can create a ring around the ball where lead is forced between the mold halves. This can also happen if there is anything on the mold faces that could prevent a tight closing of the blocks. Usually it is a tiny bit of lead.

Finally, your two five shot groups are not a large enough sample to draw conclusions about the balls. The difference in the two groups could easily happen using ten of the same balls that were absolutely perfect. Like Murphy says, "if it can happen, it will".

 

[BrownBear]

I've found that if I knock the sprue cutter over too quickly it can tear chunks out around the sprue because the lead is still not totally solidified. If I slow down, wait a few seconds after filling the mold that never happens, it cuts instead of tearing.

Spence

Yup. It will rip and tear every single time if you go too fast, but cut cleanly if you wait a little bit longer.

 

[Spikebuck]

One would be low lead temp (maybe your thermometer is off).

Thanks to all for the responses.

My thermometer stops at 1000 degrees F and I think it was actually hotter because I had lead oxide forming at the surface, which doesn't happen until a little over 1100 degrees F. :shocked2: All I know was it was darned HOT! Also, my thermometer seems to be pretty accurate on the temp when the lead actually melts at a little over 600 degrees F.

I usually mold at about 800 degrees in my Lyman molds and that works great. All I got in this case was bridging which would not allow the mold to fill.

I always had a hot puddle on top of the sprue cutter. I don't go light on the lead poured on since that just gets recycled right back into the pot anyway.

I think Spence and Brownbear hit the nail on the head...I was moving fast trying to keep the mold hot and was probably whacking open the sprue cutter too soon after I saw the puddle on top solidify.

I have to say though, compared to my Lyman steel molds, this mold is not satisfactory to me. Probably my neophyte molding skills, but the Lyman's made it relatively easy for a beginner. If my first ever molding experience was this one and this was how it turned out, I would probably give up on it.

I do have to laugh, though, when I think back to last weekend and walking around the Big Island Rendezvous in Albert Lea (which was excellent, BTW) and looking at the hand cast ball for sale there by the vendors. My worst ones look like pure gems compared to the junk ball (and flints) I saw for sale there. :shake:

 

[Rifleman1776]

1000 degrees is WAY TOO HOT. For me, most casting is done right around 700 degrees.

the lead kept bridging across the opening to the cavity

My last Lee mould did have a smaller than desirable pour hole in the cut-off plate. About one second on the drill press fixed that.
Methinks your flyers were not caused by a sprue issue but more likely air cavities in the balls.

 

[hanshi]

I generally prefer Lee molds but a number of caveats deserve attention most of which have been mentioned already. I'm slow to tap the sprue plate so to avoid the "tears". I also have a damp rag to help the sprue puddle harden well. The most common fault I experience is occasional wrinkling on the ball. For me, the most difficult ball to cast is the .600 for my smoothbore.

 

[Richard Henderson]

I have a .360 lee mold when I started using it there was marks at the edge of the sprue that should not have been there I found that when I cut the sprues the balls turned and bent the thin metal at the edge of the sprue hole down and under to the inside of the mold you could for that.
Richard Henderson

 

[Spikebuck]

1000 degrees is WAY TOO HOT. For me, most casting is done right around 700 degrees.

the lead kept bridging across the opening to the cavity

My last Lee mould did have a smaller than desirable pour hole in the cut-off plate. About one second on the drill press fixed that.
Methinks your flyers were not caused by a sprue issue but more likely air cavities in the balls.

Yep...WAY too hot and not at all what I would normally do for sure. I'm glad you mentioned slightly enlarging the pour hole as that was something I had thought about before I tried the mold again. How big did you drill yours out to?

I suppose there could have been air cavities, but if so, they must have been extremely small because I was using only those ball that were in a range of 3 grains in weight (not + or -, but a total range of 3 grains.) :idunno:

 

[AZbpBurner]

2 major problems in casting, especially with Lee molds:

1 - mold blocks not hot enough. You'll get wrinkled or incompletely filled out balls. I have a bottom pour lead pot & just put the mold blocks into the lead while it is reaching operating temp. First ball & every one afterward are perfect. I smoke the mold cavities with soot from a butane lighter flame, after cleaning the cavities prior to each use.

2 - Lead too hot. Hotter isn't necessarily better. As metals heat up it expands, the hotter it is, the less dense it is, and the more the castings will contract upon cooling. This can not only affect ball diameter uniformity, but can also cause voids to form as the poured lead immediately cools, contracts and allows air voids to form. Put plenty of metal into the pour, with a little puddle completely covering the sprue hole to minimize this.

 

[MSW]

for whatever it's worth, here's my two cents:

your lead is a bit too hot ... I usually run about 750 to 800 degrees

the funky bit at the sprue looks suspiciously like an air pocket trying to get a grip on your balls - I'd pitch anything like these back into the pot

the hole in the sprue cutter may well be too small - it couldn't hurt to enlarge it, but don't go nuts on this ... try the next size drill bit, then see how things work out

I've never had a problem whacking the sprue cutter open too slow or too fast (am I misreading the other posts?) - I wait for the puddle to harden and conk the sprue cutter with a hunk of stick from the woodpile (when the stick wears out, I throw it in the woodstove and spit off another one)

good luck with your project, and Make Good Smoke :grin:

 

[Rifleman1776]

How big did you drill yours out to?

1/2" :shocked2: :wink:

Actually, 5/32" on a .600" rb mould I will probably never use again.

 

[smoothshooter]

Two five - shot groups are not really enough to draw any conclusions from.

Five, five - shot groups with each load, maybe.

Try seating the balls with the bad sprues with the sprues down.

Bet they shoot better.

 

[tecum-tha]

The bad balls are full of air bubbles.Stuff looking like this goes back into the pot.Your weight variation tells something there.
And for me, that load seems to be awful tight,with a thin patch and a pretty large powder load.
I would start with Dutch Schultz standard load of 1.5 X the caliber for powder,weighed balls, a .570 ball and either red or blue pillow ticking (depending which one loads easier) and pre-lubed dry patches of 1:6 Ballistol:water.
Just my 2 cents....

 

[mooman76]

It doesn't matter how hot the lead is if the mould isn't hot enough. Like mentioned by some, it looks to me your mould isn't hot enough yet and that includes the sprue plate which will cool the lead down quick. It seems like the people that have the most trouble with Lee moulds are people used to steel moulds. Lee are fine, just a little different. I've never had problems with Lee sprue holes being too small either. Just need to get it up to temp.
Preheat the mould by either sitting on the edge of the pot or sticking the corner in the lead melt until it doesn't stick to the mould any more and this includes the sprue plate. I usually give a count of 24. I start the lead out high until I get going good and gradually turn it down as the lead takes longer to solidify until I get it where it works best for me.

 

[Dean2]

The guys have provided good advise. Yes, Lee molds can be made to work, just like the Sears catalogue. Personally I much prefer the pillowy softness of Purex. Get a Lyman or other quality mold and quit messing around with the cheap imitations. In the overall life of the balls you will cast the time you save not recasting balls will more than pay the difference in price on the moulds.

 

[Spikebuck]

that load seems to be awful tight,with a thin patch and a pretty large powder load.
I would start with Dutch Schultz standard load of 1.5 X the caliber for powder,weighed balls, a .570 ball and either red or blue pillow ticking (depending which one loads easier) and pre-lubed dry patches of 1:6 Ballistol:water.

The post wasn't about load, but in a nutshell, the balls cast are a different size than the commercial size the load was worked up with, which were apparently mismarked as .575 and I made the mistake of not checking them...a mistake I won't make again. So, I am doing some load tweaking again. The round bottom groove barrels seem to soak up a lot of patch, so a .575 with a .015...or now I've also tested .018, go down pretty easy.

I have Dutch's system. I appear to have an allergic reaction to ballistol as the second I get around it my lungs literally start a burn that lasts for hours and produce coughing. So I don't use it anymore. I try to take the other good stuff from Dutch and do what I can without the ballistol dry-patch.

Net, there was a lot of load workup over the summer that started with around 75 gr of powder and .570 balls and many other combinations. The group shown is not the best load...it was a load with the hand-cast balls of mine and is meant to be comparative between "good" and "bad" balls, not what had been developed as the best load. That's why I asked about using a Lee mold and not a question about load development.

 

[Rifleman1776]

The guys have provided good advise. Yes, Lee molds can be made to work, just like the Sears catalogue. Personally I much prefer the pillowy softness of Purex. Get a Lyman or other quality mold and quit messing around with the cheap imitations. In the overall life of the balls you will cast the time you save not recasting balls will more than pay the difference in price on the moulds.

Realistically, most of us would prefer Lyman moulds over Lee but budget considerations force the decision to buy the less cost item. That said, a Lee mould will provide many years of casting with great results. Of all I have had, only the one mentioned needed the pour hole enlarged. Many items we buy and use, not just ml related, often need some tinkering and adjusting to work as we want them. Drilling that hole is not a big deal, IMHO.