Pouring Slowly

[justindad]

Is it best practice to pour lead as slowly as practical into the boolit mold?
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When I take 1-2 seconds to fill up a 160 grain .357 cavity (with two square lube grooves and a cannelure groove) I get better fill out than casting quickly. I’m pressuring pouring from a bottom pour RCBS pot, and sticking the nozzle into the cavity of the sprue plate. Keeping the hot nozzle very close to the sprue plate seems to keep the sprue puddle over the previous cavity liquid while I’m filling the next… which was very beneficial tonight.
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If I go so slow that the sprue puddle over the previous cavity turns solid before I finish filling the next cavity, I loose fill out quality. I noticed this by watching how the lead back fills into the previous sprue puddle, which is my indicator to move to the next cavity.
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Are there reasons for pouring lead into the cavities a bit faster?

[Winger Ed.]

Faster works better for me.

A slow pour will probably need to have the pot & mold a little on the hotter side.
But if that method gives you good results--- I'd recommend to keep doing it that way.

[Land Owner]

Faster fill works for me too - and about 2% tin in the alloy. Spru from one cavity solidifying before filling the next - that's pretty slow - but if that is working for you, who am I to judge.

There is a "socket head cap screw" for adjustment on the RCBS Pro Melt to allow for greater/lesser flow through the nozzle. Adjust that for faster flow and allow a little sight distance between the spru plate and nozzle when the mould is moved across the resting guide.

If the spru plate is hot, the mould is hot, the melt is hot, and the alloy is right, complete fill out, no wrinkles, no frost, consistent weight boolits in an even tempo fall from the mould, and a significant number of boolits can be made in an hour.

https://i.postimg.cc/HsMTS9sS/Pro-Melt-Adjustment.jpg

[high standard 40]

Sometimes, an individual mold can be a story unto itself. That being said, the best advice I can give is to experiment with every aspect of casting technique with each mold you use. Alloy, pot temp, mold temp, fill rate, sprue size, how close the sprue plate is to the fill spout, how long you wait to open the mold.....all can change the way a mold behaves. Pay attention to those changes and keep notes. Find what each mold you have likes.

[JonB_in_Glencoe]

justindad,
On average, I place the sprue plate about 1/2" below the spout and I set the alloy stream to fill the mold as quickly as possible, but not so fast as to cause splashing out the sprue plate when the cavity is full.

But as High Standard says... Each "individual mold can be a story unto itself"


Sometimes, an individual mold can be a story unto itself. That being said, the best advice I can give is to experiment with every aspect of casting technique with each mold you use. Alloy, pot temp, mold temp, fill rate, sprue size, how close the sprue plate is to the fill spout, how long you wait to open the mold.....all can change the way a mold behaves. Pay attention to those changes and keep notes. Find what each mold you have likes.

[justindad]

Normally, I start pouring the lead on the sprue plate at the end that gets wacked with the mallet. With this mold, I get better fill out with mold by starting at the pivot end… especially for that last cavity.
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I’ve been seeing improvements after spraying with brake cleaner and scrubbing the cavities with isopropyl alcohol, so maybe there’s still a film of mystery mold release in there from the previous owner.

[Bazoo]

You can try the Bazoo method of cleaning. Lighter fluid in the hot cavity. Get the mould almost as hot as you’ll cast with it, open the sprue cutter and fill the cavities with lighter fluid. It will boil, but not burst into flames. It scrubs oil out like nobodies business.

[Sig556r]

Faster works better for me.

A slow pour will probably need to have the pot & mold a little on the hotter side.
But if that method gives you good results--- I'd recommend to keep doing it that way.

^^^ what he said

[FISH4BUGS]

justindad,
On average, I place the sprue plate about 1/2" below the spout and I set the alloy stream to fill the mold as quickly as possible, but not so fast as to cause splashing out the sprue plate when the cavity is full.

But as High Standard says... Each "individual mold can be a story unto itself"

I cast with a ProMelt and have the mould about 3" below the spout.
I think the added distance helps pressure fill the mould and the bands....or so I would think.
That seems to work for me.
i would experiment with a longer drop from the spout and see what that does.
I run at 750 degrees and cast with 4-6-8 cavity H&G moulds.
Once those puppies get warmed up, production is astounding.

[mdi]

I haven't found much difference keeping the spout 1/4"-3/8" from the sprue plate and leaving a big puddle. Works on most of my molds. On larger bullets and shot gun slugs I like a fast pour and big puddle...

[bangerjim]

As fast as humanly/mechanically possible!!!!!! Don't give the stream a chance to lose its heat. You want the Pb to cool IN the mold cavity, not in the stream flowing into it!

I fill 6 cavity molds at the rate of 1 cavity every second. The only time I cast slower is if the particular mold requires pressure casting for success.

You just need to play around with each of your different molds and find out what each one likes and write it down on the storage box for future reference.

[megasupermagnum]

Out of I don't know how many molds, I have yet to find one that does best with a very slow pour. Certain molds like the JT ball mold that only vents through the sprue hole does seem to like a more moderate pace. For the most part though, faster is better. Gravity isn't enough to fill a mold. You need the pressure from the lead to force into the mold cavity. Some molds I find only do really good pressure pouring, especially with pure lead.

[Bazoo]

I get the best fillout with about a 3/4” to 1” freefall. And I get the best results with a large sprue puddle that doesn’t spill off the sides or adjacent cavity. Course I’m ladle casting too.

[Cosmic_Charlie]

I recently got an Arsenal 38 cal 170 Keith style mold that had some fill out issues. A hotter preheat and higher alloy temp are doing the trick. I could try some break cleaner I guess but i did clean it several times between heat cycles already. I think the interior surface shape can cause some molds to be problematic, particularly in the smaller calibers.

[Bazoo]

I see some shapes being harder to get good results than others also.

[brassrat]

I had a very cold 4 banger that totally locked up, yesterday. It sat on my heating coil for hours, but this time, I used a heavy shooting plate to cover the coil. I wish I tried dipping the mould first. I also wish that I poured so slow as not to happen because one of the mould screw holes snapped off on the handles as I tried to beat the locked up mould, open. The Lee handle took hours to grind down to get it to work on the Lyman mould and several more to redrill new holes and finally get them to work. One funny thing was remembering picking up ( as in look for price) a real Lyman handle set at the, not so local, gun store and thinking that I was lucky to not have to drop $40 on the used set. Just on Wed.

[GregLaROCHE]

I’m always trying to pour as fast as I can, but I’m normally casting 400-500 grain boolits. I can’t see any benefits to casting slower.

[JonB_in_Glencoe]

I cast with a ProMelt and have the mould about 3" below the spout.
I think the added distance helps pressure fill the mould and the bands....or so I would think.
That seems to work for me.
i would experiment with a longer drop from the spout and see what that does.
I run at 750 degrees and cast with 4-6-8 cavity H&G moulds.
Once those puppies get warmed up, production is astounding.

3" ...huh?
I don't know if I have enough room on the Lee 4-20 ?
I've tried other distances and 1/2" is my happy medium where I can still see what's going on and have the least amount of splashing. The longer the distance, the more splashing ...I hate splashing.
Anyway, if I need better fillout, I cast with a hotter mold.

[Shuz]

I use an RCBS PRO-MELT and have my moulds about 1-1/2" below the spout. I pour as fast as I can and adjust the flow rate as the pot draws down with the Allen screw as mentioned by a previous post. I use a thermometer to monitor my pot alloy temperature. My pot runs from 690 to 710 degrees and that works fine with brass, aluminum or mehanite (iron) moulds once they are up to operating temperature.

[robg]

some molds like a fast straight pour ,some like the lead to swill around the sprue plate first

[Hanzy4200]

Faster is better for me, but within reason. I have found that some of my largest molds, 400 gr+, do better with a slightly slower pour.

[Green Frog]

For me, the startup method is "Hot and Fast". On some moulds and with some alloys I have to make some adjustments, but not many. Hollow point and hollow base moulds sometimes require a slight tilt to the mould for best results, but again, hot and fast seems to work. I generally have the sprue plate within about an inch or less (usually less) from the spout.

BTW, I've cast with a couple of the 10# Lyman pots and an early 20 pounder, a RCBS 20 pounder and a couple of Lee 20s as well. All seem to respond well to this technique. YMMV!

Froggie

[jsizemore]

For me when a mold needs a slow pour rate it's usually not venting like it should. I break the top inside edge of the mold with a stone to about the depth of the vent lines. I also clean the vent lines. They only get clogged if I pour at too high a rate or hot alloy. I've gotten around it by directing the lead stream to one side of the sprue hole.

[justindad]

I’ve been thinking about poor venting, but the vent lines are clear. This mold has curved vents like what I see in Miha molds, not like the straight vents in my newer NOE molds. When I pour the lead, I have the nozzle touching the sprue puddle, which I think helps because the nozzle keeps the stream & puddle hot while air slowly escapes.
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Maybe I need to drill out a larger diameter hole in the sprue plate? That way air could escape out of the top of the cavity and pouring faster wouldn’t plug the sprue hole before the cavity is completely filled.
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Thinking about it more, the RCBA pot has a larger diameter stream of lead than my 8lb Lee pot. A larger diameter stream would eventually require a larger diameter sprue hole.
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Also, I will try that boiling lighter fluid trick.