How can I eliminate spashing on the nose of large boolits?

[happy7]

On big boolits with long noses, I get splashing on the nose with a bottom pour. I prefer bottom pour, but with these bullets I can cast beautiful bullets with a ladel, but just cannot get rid of the splashing out of a bottom pour. I have tried all sorts of things like tipping the mold (eliminates splashing on one side of the nose, but the other side is worse), pressure casting (helps, but not totally eliminated), slow flow, fast flow, long drop, short drop, hot mold, cold mold, different alloys (20:1 works best, but still better with lade, also tried WW, WW with mono).

I know some of you say you can bottom pour any bullet well. I would love to know how you do it. Please try to keep this thread on topic. I don't really want to start another bottom pour vs. ladle thread. We have a lot of those. I spent a half hour reading a lot of them looking for the answer to this question with no success. Not that it isn't somewhere in here, but I couldn't find it.

[knifemaker]

I am not quite sure what you mean about splashing on the nose. If you are referring that the nose portion is not fully filled out or has a wrinkle, you may need to bring your pot temperture up or your mold may need to be hotter when you cast.

I cast large 350 & 405 gr. 45/70 bullets and do not have a problem with a bottom pour pot. I do preheat my mold on a lab type hotplate to around 400 degrees. Also some mold designs require the lead to be hotter then others for perfect fillout.
Since you are not getting it with a ladle, does your bottom pour spout have a tendency to leak and you have a gob of lead hanging from the spout when you start to pour. If you do, knock that gob off with the side of your mold then pour. That gob of lead will have be cooler then the lead in the pot and can be your problem by cooling to fast before it hits the bottom of the mold.

[deltaenterprizes]

Could you mean "flashing" as in lead flowing between the blocks?

[Bass Ackward]

Yep, don't take this wrong, but I got no idea what your talking about.

Coarse I do ladle everything over 400 grains. But this isn't because of the nose, but trapped air toward the base.

If you have particular trouble with heat on the nose of some design, then pour the bullet and watch the sprue harden (big point here) then rotate the mold over so that heat can rise. I do this for hollow points and long rifle bullets so I don't have to mold like a madman.

It is also a more efficient way to heat the mold and the heat sink attached called the handles since the handles are at or around the nose area. Saves for over heating everything just to find the sweet spot.

[44man]

Yes Bass, confusing! :holysheep
I get a lot of "splash" on steel targets but I can't duplicate it in the mold. [smilie=l:
We need a picture.

[mooman76]

If you are getting flashing, the little fins on the nose. I don't bottom pour but sound like too much pressure is opening the nose up a might.

[happy7]

Well shoot, if nobody even knows what it is, no one will know how to solve it. Darn. But I will post some pictures down the road. It only happens on large bullets, mostly over 500 grains, with long noses. The lead hits the bottom of the mold and splashes around the cavity and leaves the nose with pits in it. I am not talking about flashing or wrinkles.

[dragonrider]

I also do not understand nor can I picture "spashing". You must tell us, or for much better understaning, show us what the boolit looks like, as apparently you boolit does not look good. A properly heated mold will give good boolits so just my guess for now but sounds like an uneven heat problem.

[BeeMan]

Happy,

I saw something similar when I started using group buy aluminum molds. Previous experience was with RCBS 2 cavity molds, so once warmed up they held temperature fairly well. The answer for me was a hotter mold.

Don't try to do this by raising the temperature of your lead though. Increase your casting pace. If you are not preheating the mold on a hot plate or by immersing in the pot, try it.

Good luck and let us know how you solved the nose defects.

[Rockydog]

I bottom pour 405 gr. 45-70s and don't have problems once I get the mold warmed up. For the first few bullets I get some nose wrinkles etc. also. But once the mold is up to temp. things roll right along. Most times I preheat the mold on a hot plate with the bottom (closest to the nose) sitting on the plate. This reduces the number of discards. RD

[GabbyM]

Wrinkles on the nose would be to cold a mold block. Catch is as the blocks heat up with the big bullets you get shrinkage at the center where the cavities come close together. If you can’t find a happy median then pressure pouring with a ladle usually works.

What I’ve never figured out fully is why my Lee pot won’t work holding the mould up against the spout to pressure poor. It works to a point but the Lyman ladle with a spout must have more pressure at the spout. I pretty much ladle pour starting with my 325 grain 45 then I also use pressure poor on my tiny Lyman 225646 to get the little groves in the nose filled out nice.

[scb]

I've got to agree. It sounds like you're running too cold.

[RobS]

Well shoot, if nobody even knows what it is, no one will know how to solve it. Darn. But I will post some pictures down the road. It only happens on large bullets, mostly over 500 grains, with long noses. The lead hits the bottom of the mold and splashes around the cavity and leaves the nose with pits in it. I am not talking about flashing or wrinkles.

Have you tried a swirl technique that has been mentioned from time to time here? Gear and onondaga have mentioned this a few times in the past several months. Simply align the lead stream so it will hit the bevel of the sprue plate so the stream will start a swirl as the lead continues on down into the sprue plate hole and into the mold cavity. Holding the mold at a very slight angle while doing this can even help. I like to straighten the mold back up towards the end of filling the cavity so the base fills better and expecially with one particular mold I have but the others it doesn't really seem to matter if I straighten the mold up or not.

[ColColt]

Those "pits" on the nose-could it be trash in the mix? I've had little pock marks on the nose(ogive) and base at times that I'm sure was just small particles of dirt or whatever. I stirred the pot good and fluxed with sawdust and it brought more dross to the surface. I skimmed it off, put another tablespoon of sawdust on top the mix to minimize oxidation and no more pits.

[onondaga]

If the Splashing in the nose you mention is turbulence, the swirl casting method discussed in another thread may help you.

However pitting is not generally associated with splashing.

Large molds can be fussy to a lot of technique nuances. Swirl casting is the first thing I try when I encounter a fussy mold. Here is a link to that thread:

http://castboolits.gunloads.com/showthread.php?t=119664

It is a long one with comments, read it out, and you are welcome to PM me with any specific questions.

Gary

[onondaga]

Do your 'Pits in the nose" look like small rough irregular specs or do they look like small rounded craters or dimples. Are they wrinkled grooves? DO they have a micro porous surface. Are your boolits in general shiny, satiny or frosted? Are there zones on your boolits that have different textures? A photo closeup in macro would be valuable to help you. Repeated bullet surface defects are very specific in nature and can be figured out from a good photograph.

Post a close-up photo.
While you are taking pictures, a close-up of a few sprues from boolits that had the problem would also be valuable.

Gary

[gefiltephish]

Hopefully my photo attached ok. I suspect that this is what the op is referring to as "splash". Spinning the bullet in my fingers, this is definitely not what I'd call wrinkling. This is 170gr .314 out of a 3 cav brass from Accurate Molds. It's the only one that I've had this happen. This is the only bullet I have that is this long relative to it's diameter. I preheat on a hotplate. I use a PID with a Lee 4-20. I've tried numerous techniques including swirling. I have had good bullets but it requires very high temps, both melt and mold, and pressure casting. Unfortunately, those same high temps makes bullet release nearly impossible. The next thing I've been planning to try is ladle pouring.

[onondaga]

Your picture shows cold mold wrinkle also known as cold short wrinkle from a cool mold.

Your alloy was fluid enough to pour obviously but the mold temperature was significantly cooler than 100 degrees below fluidus of your alloy and that caused a break or wrinkle between an area that flash froze first against the cold mold and the remainder of the boolit. If the mold was colder you would have gotten even more wrinkles.

A similar effect can also be achieved with a break in the flow when pouring into a cool mold and the wrinkle denotes where the flow paused or stopped and the mold temperature was too cool to compensate and allow the metal to fill out the mold. Insufficient Tin can also be a factor as Tin lessens the surface tension of bullet alloys and allows them to flow better and fill-out a mold better.

A break in the flow or a pause in the flow is generally caused by movement of the mold during the pour that changes the flow between pouring dead center and hitting the slope of the sprue gate hole. When you go back and forth from center pour to sliding the gate slope with the flow it makes the flow wiggle or pause. That type of flow into a cold mold registers as wrinkles.

An eye level view and steady hand practice will correct that. Elevate your pot with sturdy support to get the spout at eye level and have sufficient lighting so you can clearly see where your flow is going every time.

That type of wrinkle and surrounding surface textures are not related to hot spot turbulence overheating a zone of the mold cavity.

Gary

[geargnasher]

As usual, Gary explains it very well.

I apologize for linking this oversized picture ONCE AGAIN, but I think I know what you're talking about with "splash". The boolit on the riight has a splash in the nose, where the stream went straight up the side and froze while the rest of the alloy filled around it, leaving a void.

My own experience with this has been that, first, the mould was too cool in the nose are, for reasons explained earlier by Bass and others. Second, "swirl pouring" greatly reduces this once you get the hang of it. Third, long, skinny boolits and big boolits just seem to like being ladled, not sure what the difference is, because it doesn't seem to matter whether you contact-pressure pour or stream the alloy in with the ladle, it always seems to work better. I can pressure-cast with a full bottom pour pot and STILL get wrinkled or "splashed" noses with big or long boolits unless I get the mould pretty hot, hot enough for a nice light frost, just like the ones in the middle of the pic below.

Gear

http://castboolits.gunloads.com/attachment.php?attachmentid=28007&d=1293562439

[williamwaco]

I can eliminate the splashing you describe in two ways.

1) cast from a nearly empty bottom pour pot. No more than an inch or two of melt in the pot.


2) ( My preference)

Very carefully place the mold on the mold guide so that the sprue stream impacts aproximately one half in the sprue hole and one half on the "funnel" in the sprue plate that leads into the actual sprue hole.

If you are using a multiple cavity mold. Place the mold about 1/2 inch below the spout but not quite far in enough to be under it ( spout). When you open the spout, you want the metal stream to initially hit the sprue cutter plate on the top of the plate. Immediately slide the mold further under the spout until the stream impacts the side of the "funnel" in the sprue plate hold it there until the cavity overflows then slide it further under the spout to the next cavity. Avoid allowing the stream to enter the sprue cutter hole dead center. That will almost always cause splashing on long bullets.

PS. Casting with hot mold and hot melt also helps.

[geargnasher]

In addition to dropping the stream right at the edge of the hole, tilt the mould about ten degrees by lowering the handle end. It works best for me dropping the stream in the right side of the mould so it creates a clockwise swirl (same as the toilet water does in the Northern hemisphere). The combination of off-center pour and angled cavity makes the alloy deflect off the side and spiral around, which I think helps eliminate at least some trapped air back out the sprue hole.

Onandaga (Gary) first gave me the tip, it's sure been a good one. Thanks, Gary.

Gear

[theperfessor]

Let me share my experience. I think I know what the OP is talking about. Two years ago I made a mold for a 5 lb lead hammer out of steel for a site benefit auction. Once I got it up to about 100F cooler than the lead temperature it cast very nicely. Last year I made two 2 lb hammer head molds out of aluminum, again to make hammers for a site auction. I had a tough time getting rid of the speckles until I got the mold up above the melting point of the alloy. The molten lead was bouncing off the handle section inside the mold and splashing and cooling in little splatters that were incorporated into the surface. The molten alloy wouldn't remelt the splatters. They always showed up in the bottom half of the mold, I never got them above the handle line. It is a different phenomenon than cold shut wrinkles, although it shows up along with them at cooler temperatures.

I'm not going to make any more large molds out of aluminum. They lose heat way to fast. I won't make any recommendations to the OP, but more heat was the solution to my problem.