My experience today

[jforwel]

Unboxed the new Lee Pro 4-20 burned off the oil and filled it with 50/50 WW/lead. I had been using the small 8lb Lyman pot and dipper for the past year. This was my first go with a bottom pour. I was using Lyman mold 452664.

First I found out that the temp controller on the Lee pot is junk. No matter where I set it the pot went very hot. I had to unplug it from time to time, so I'll probably add an in line rotary switch to make that easier. The spout worked fine but I had no idea what constituted a good flow. I just used what worked but did not try different settings and separate the boolits to be measured and weighed later.

I used the Kroil treatment on this mold and Bull Plate lube and boolits just fell out. I did have a burr on the sprue plate but sanded that off. In measuring the boolits I found the base band to be larger than the middle driving band by a couple thousandths. Also weights seem to vary by as much as four grains. I did not separate the boolits by cavity so I don't know if there is any variation there.

Questions: Can the temperature and/or the flow rate cause weight and size variation in the boolits? Should I set the flow rate to max or just what fills the cavity well? I saw the poll on temperature settings and a lot of people said they go wide open. Mine will get up near 900, is that too hot?

[Recluse]

Questions: Can the temperature and/or the flow rate cause weight and size variation in the boolits? Should I set the flow rate to max or just what fills the cavity well? I saw the poll on temperature settings and a lot of people said they go wide open. Mine will get up near 900, is that too hot?

I guess I'm fortunate--my old Lee Pro 4-20 holds temperature very consistently and very well so long as I keep it at least 2/3's full of alloy. Once it gets down to a quarter of a pot, temp definitely starts getting way hot.

There are boolits and alloy mixes that I will crank the pot all the way up for. According to my thermometer, I've had the alloy up just shy of 1000F, which is too hot for even me. But there are some combos that I like to cast at ~900F and then water-drop. Gives me a really nice hard boolit for some very good high-velocity target rounds.

As far as the bottom pour and flow-rate is concerned, I adjusted mine for a flow that is on the quick side. I had experimented, based upon someone here's recommendation, with a flow that was barely faster than a trickle and found that I was not getting great fillout--especially with aluminum molds, and even moreso with aluminum molds for larger pistol boolits. So I adjusted the flow to run a bit quicker and it has worked perfect ever since.

For rifle boolits, I continue to ladle pour. Just seems to work better that way.

Temperature affecting size of boolits? I've found that depending on the combination of factors (alloy composition, temperature, water-dropping, mold temp and composition), temperature CAN make a difference in boolit size.

That doesn't really affect me as I size every single boolit I cast, no exceptions. I normally lap all my molds as soon as I get them as I'd rather have a boolit that is one or two thousandths too big than too small.

[runfiverun]

yes,no,yes.
and take the top off and adjust the contacts.

[44wcf]

I am using 2 of the Lee bottom pour pots. The temp. control works fine on both. Yes I think 900 is to hot. And I think with a little experience and time your bullets will be more constant.
44wcf

I guess I'm fortunate--my old Lee Pro 4-20 holds temperature very consistently and very well so long as I keep it at least 2/3's full of alloy. Once it gets down to a quarter of a pot, temp definitely starts getting way hot.

There are boolits and alloy mixes that I will crank the pot all the way up for. According to my thermometer, I've had the alloy up just shy of 1000F, which is too hot for even me. But there are some combos that I like to cast at ~900F and then water-drop. Gives me a really nice hard boolit for some very good high-velocity target rounds.

As far as the bottom pour and flow-rate is concerned, I adjusted mine for a flow that is on the quick side. I had experimented, based upon someone here's recommendation, with a flow that was barely faster than a trickle and found that I was not getting great fillout--especially with aluminum molds, and even moreso with aluminum molds for larger pistol boolits. So I adjusted the flow to run a bit quicker and it has worked perfect ever since.

For rifle boolits, I continue to ladle pour. Just seems to work better that way.

Temperature affecting size of boolits? I've found that depending on the combination of factors (alloy composition, temperature, water-dropping, mold temp and composition), temperature CAN make a difference in boolit size.

That doesn't really affect me as I size every single boolit I cast, no exceptions. I normally lap all my molds as soon as I get them as I'd rather have a boolit that is one or two thousandths too big than too small.

[DLCTEX]

Aluminum moulds in particular can overheat in spots causing shrunken bands. The thinner portion of the mould will get hotter, leaving the nose area and base (due to sprue plate absorbing heat) cooler, thus larger. That is one of the reasons why different moulds can require different temps. There will be a temp of alloy and speed of casting that will cast, and drop, boolits well, that can take experimenting to find. Some use a cooling method to facilitate this. The Lee TL moulds seem to be prone to shrunken bands.

[Paladin 56]

yes,no,yes.
and take the top off and adjust the contacts.

Well said.

My Lee pot has worked well since day one. I just didn't know it until I worked with it for a short while. It also works well with large rifle bullets in the .458" - .475", 500 grain, multiple cavity, range.

[Walter Laich]

As to flow: I like a steady flow, one that fills a 200 gr .45 Colt mold in about 5 seconds (that's all 4 cavities.) I like to overflow so I have one large spur to remove. Like was mentioned at top, too slow is not a good idea. If the lead is splashing out of the cavities you are too far open

walt

[Dale53]

Lead flow in a bottom pour pot can vary depending on YOUR particular desires.

I use RCBS pots (22 lb bottom pour) and I continually adjust my flow (keep it the same as the amount lowers in the pot) by leaving the adjusting screw loose to finger operate.

My best and most consistent results come when the lead flow is just above dribbling. A slow flow works best for me. I keep the mould sprueplate about 3/4"-1" below the spout.

I NEVER cast over 800 degrees. Most of my bullet casting temps run 725-750. I use a "manicurists fan" to cool my mould. It allows the sprue to cool in two seconds and maintains the proper operating temperature of the entire mould for continuous casting.

I have both iron and aluminum moulds (about 70, last count). I cast several thousand bullets a year (over 10,000) for a reference. That's not a whole lot of bullets but enough to "keep my hand in"...

The important thing is to do what works best for YOU with YOUR equipment.

FWIW
Dale53

[jforwel]

Thanks for the replies, you've given me some ideas to work with. Recluse you mentioned aluminum molds having trouble filling out because of a too slow flow. I didn't mention in my post but I also tried a Lee mold and never did get it to fill out properly after I used the Lyman mold. Maybe the flow was the issue as you stated. Thanks for that.

Now I am off to the work bench to lap the Lyman mold and play with the contacts.

[Phat Man Mike]

the best thing is that you can remelt what you don't like! I've had to tweak mine a little for some molds ! but use what you like best IMO