Getting consistent bottom pour

[GSSP]

I've only run my new RCBS Pro-Melt 2 a few times. The PID is right on at 700 deg when compared to my new RCBS lead thermometer, which was my target temp. Outside temp was about 34 deg. Once I got my molds up to temp I had a hard time trying to figure out what method was the best to get a clean pour. My nipple had a leak so after awhile it would create at little spire of lead and it would get in the way of sliding the mold block forward and back when sitting on the Mold Guide. I dispensed with using the Mold Guide. It seemed if I did single pours into each cavity it "might" get a clean bullet but if I tried to run a continuous stream of lead the lead would fill the current cavity and before I could slide the next cavity under the lead stream, it would overflow into the next cavity. This would get a partial fill, which would freeze, before I could get the lead stream directly into the next cavity.

1. Continuous stream or pour/stop/move...pour/stop/move, etc.?
2. I run LBT molds with their "continuous" sprue trough so should I keep the nipple super close to the sprue plate or lower the block 1/4", 1/2" , 3/4" below the trough?
3. I was trying to follow Rick Kelter's/LASC suggestions of keeping my temp to 700 deg. Should I run a bit hotter?

I was running a 4 cavity, 44 Special, 255 gr and a 2 cavity, 480 Ruger, 390 gr.

HBO! Help a Brother Out!

Alan

[Minerat]

First off tilt the mould so any over fill runs into the last cavity filled. So if you fill from front to back raise the back handles of the a little so when the first cavity is full the over fill will spill off the front of the mould into a ingot mould or small catch pan and preceded filling the remaining cavities. For large bollits I use a continuous poor for the little one like .172 fill each cavity

[jdfoxinc]

Higher temp. I run 92-6-2 at 750-800f. Pure lead @850 deg.f. I reduced my culls to 20% from 40%. And the next cavity doesn't freeze before I move the mold, even casting 90 gr pills.

[Springfield]

Mold is too cool. IMHO. If it was up to temp the lead wouldn't have time to cool so soon.

[ioon44]

I run my pro melt at 725 deg F with a PID controller. I use the same temp with COWW and 6-2-92, I use the mold guide as close to the nipple as I can and still be able to tip the mold to run the over fill to the last cavity filled.

[scotner]

<I've only run my new RCBS Pro-Melt 2 a few times. My nipple had a leak so after awhile it would create at little spire of lead and it would get in the way of sliding the mold block forward and back when sitting on the Mold Guide.>

I had the same problem with my Pro Melt from the first time I used it. I called RCBS and they sent me a new nozzle shut off pin and no more problem after that.


1. Continuous stream or pour/stop/move...pour/stop/move, etc.?
Usually pour/stop/move works better for me.

2. I run LBT molds with their "continuous" sprue trough so should I keep the nipple super close to the sprue plate or lower the block 1/4", 1/2" , 3/4" below the trough?
I prefer 1/4" or so.

3. I was trying to follow Rick Kelter's/LASC suggestions of keeping my temp to 700 deg. Should I run a bit hotter?
I start out at 725 or so and come back to 700° after everything heats up good.

I was running a 4 cavity, 44 Special, 255 gr and a 2 cavity, 480 Ruger, 390 gr.
When running these large boolits the level drops quickly and I have to constantly adjust the stop screw to open more as the lead level falls. I try to run similar size molds together, such as the 30 cal 245 gr and a 45 cal 200 gr like you were doing since they have a similar fill rate. I prefer to fill them quickly.

[kevin c]

I agree with the mold maybe being too cold.

Are you casting outside in that 34 degree weather? Is there any wind? What material are your LTB molds made of? How is the alloy flow from the pot: slow or fast? You are casting one mold at a time, not alternating?

You may be getting your molds up to temp before casting, but I wonder if they are staying there. If they're cooling off too fast the alloy may freeze before the pour is complete, especially if the flow rate from the nozzle is slow, whether from the get go or from less alloy being left in the pot. My aluminum multi cavity molds need a rapid cadence and quick flow to stay at temperature, and even in California's mild winters the temp change means casting now needs more attention to that issue than during the summer. For instance I haven't gotten the knack of casting two molds alternating (they cool down too much) and I don't think I'll try to improve on that until warmer weather makes it easier.

Perhaps I'm misunderstanding: are you pouring without any guide at all? If not, I'd think it hard to maneuver the mold from one cavity to the next consistently. If you are (I like the NOE aftermarket guide a lot), I'd suggest getting as close to the nozzle as will still let you see what you are doing and allow manipulating the mold without banging it into the nozzle; there'll be less cooling of the alloy with a shorter drop and also if you adjust for more flow.

[lightman]

I run my temps at 725º and I have the mold about 1/2 inch from the spout. I have the flow adjusted at a pretty fast rate. I tilt the back (side closest to me) up a little and start at the cavity away from me. Even with a mold with a trough I stop and start the flow at each cavity.

I have a brand new aluminum mold that I have not cast with yet. I'm hoping that I don't have to change my casting methods too much. Its my first aluminum mold in 45 something years when I tried and discarded a 2 cavity Lee mold.

[OS OK]

Use a mould guide...725º F. is a good all-around temperature...pour close to the sprue fill hole, hit the hole dead center without ricocheting off the sides of the hole where the sprue plate can rob the temperature from the stream...pour continuous with as fast a stream as you can manage and that extra lead on the sprue plate will keep the sprue plate as hot as possible where it won't rob you so bad on a bad ricochet type pour.
Hang in there, it takes some time to get the eyes + brain + muscle coordination running smooth but it'll happen and the next time you talk about this you'll be advising another fella with the same problems.

[Dusty Bannister]

I agree with others that the melt temp might be a bit cold. I like 725F and when casting in an unheated shed with exhaust fan, the mold gets cool faster. That mold body takes a lot of heat from the alloy so you might need to speed up the cadence as well. Tilting to avoid over flow going into the next cavity is a good practice. I do not use the flow adjustment screw to control the flow, you do that with the handle on the pot. I always flow wide open, unless casting the 22's and then use less alloy in the pot which in turn lowers the pressure and speed of the flow. Not using the mold guide adds to the variables such as how the alloy enters the mold through the sprue plate, as well as heat loss from an excessively long drop from the nozzle to the mold.

The observation that you have solidified alloy hanging off the nozzle shows the pot is too cold. And the ambient air temp is cooling the lead before it can drop free. Then when you open the nozzle, it might fall and interrupt the flow into the mold. Turn up the heat, this is winter time.

[Petander]

Yep,a hot plate and a higher temp.

I have no PID but my Pro Melt is at full 800 pretty much all the time. I use two molds most of the time.

EDIT: doing 12 gauge Lyman pellet slugs right now @ 850. Hard alloy.

[popper]

Sometimes when you move to the next hole the sprue hole will plug due to cool plate before the cavity can fill. Start/stop solves the problem.

[35isit]

In my experience only. If you are in a out building use a space heater and raise the ambient temperature. Use your mold guide and pour in a continual pour. When the first cavity fills it will bubble. Like a pop bottle gets full. Then move to the next one. Make a big puddle on the sprue plate. It will keep the plate hot. You will eventually get your cadence down. I have two LBT and one Ideal mold someone converted. The cast wonderfully this way.

YMMV

[georgerkahn]

I had immediate thoughts to hopefully provide some answers, and in reading others' replies, 35isit pretty much voiced exactly what I was going to write! In an area generally too cold for my garage-casting during most winter months -- it's 3* F as I type this -- I've learned *I* -- using similar RCBS pot -- may cast reasonably well in ambient temps higher than ~42* - 43* F. In frustration, I gave paired two milk-house heaters -- one on each side of casting bench -- with marginal success. One of my major challenges is, too, the bottom spout "freezing" (not really freezing, but just too quickly getting below alloy melt temp). I have a mini- butane torch to address that. My empathy to you -- the reason why I do most all my casting in warmer months...
BEST!
geo

[Echo]

I was running a 4 cavity, 44 Special, 255 gr and a 2 cavity, 480 Ruger, 390 gr.
When running these large boolits the level drops quickly and I have to constantly adjust the stop screw to open more as the lead level falls. I try to run similar size molds together, such as the 30 cal 245 gr and a 45 cal 200 gr like you were doing since they have a similar fill rate. I prefer to fill them quickly.

I like to keep a full furnace, starting out full and adding (warmed) ingots as possible without overflowing. This keeps a fairly constant head of pressure, and little change in temperature due to the thermal inertia of 9 lbs @ 720* versus 1 lb @ 350*. Typical drop is to ~660-70*, then back up to 720 within 3-4 minutes, with my molds non-complaining.

[HangFireW8]

I have 3 brand name uncalibrated dial thermometers, that don't agree with each other, or with my calibrated PID pot. For that reason I ignore exact temp suggestions found here and go with directions of heat (hotter, cooler) from experienced casters.

My experience is that over 290-300 grains, current bottom pour pots do not flow fast enough for moderate temp casting, even though those temps are no problem with ladle casting.

So I agree with several suggestions already made here... for bottom pour... Preheat mold more and turn up the melt temp some.

[Winger Ed.]

I've got a older Pro-melt and don't use the guide either.
Different things work differently for different folks:
I set the mold & handles on top to let it get or stay hot.
For the temp, I start high and if/when I get 'frosted' castings, I just back off the temp until they shine and still fill properly.
I'm not competing for the Bianchi Cup, or expect to set any new rifle range records, but this is simple, fast, and works well for me.

[GSSP]

All great advice, of which I used much of it this morning. Much better but not awesome. It was 40 F in the garage this am. I ran the pot at 750. I'd start a stream running and quickly put the mold under the stream. i'd like to run the NOE mold guide (NOE is just down the road from me) but it seems my pour stream goes one way/slight angle for a second or two then straight after that. Thinking I might need to cool the pot and clean out the pour spout? Any good suggestions on that issue?

Alan

[popper]

I use a dental pick but any stiff wire pushed up the spout when the pot is hot and valve open will clear it up.

[Static line]

I have a needle that is locked into my channel locks and always ready to go if and when I need to run it up through my Lee Pot's spout.