I have been casting the lee 310gr gc bullet from wheelweights for my 44s and have been having some problems with the bases filling out. I have about 50% reject rate. (If the base doesnt fill out right then the gas check wont stay on). I have been fluxing with parifin wax but really havent noticed if it is helping or not. Im casting at about 700-750 degrees. I have added lead free solder to increase the tin but havent noticed much difference in my # of rejects. My question is, is 50% rejects a normal amount? and what tips can anyone give to cast more consistantly? Thanks....Flinch

A 50% reject rate is not normal. Some molds (esp. Lee molds) are troublesome, but ther are some things to try.

IF the bullets aren't falling out with a slightly frosted look, they can stand to be hotter. 700-750 is probaly hot enough if the reading is accurate, so casting faster (allowing more heat build up in the mold) may help. Some Lee molds just require me to cast at near that frosted look to get decent bullets with a low rejection rate. BTW: a bit of "frosting" does no harm...if it offends you, can polish it to bright witha soft rag).

Not filling out at the base may be due to a cool sprue plate. Letting a good bit of alloy "puddle" on the plate helps warm it, supplies added pressure to fill out a balky mold. On bullets of this size, can actually see the puddle from a little depression at the instant it starts to solidify.

If you run the mold and lead temperature up to where it takes a short wait (proably about 6-10seconds) for the sprue to solidify, it's about as hot as you can run.

Smoke the mold...just apply a layer of soot from a butane lighter or kitchen match. Usually that won't help an edge filling defect like this, but it can't hurt.

Try these ideas before looking at any mold modifications.

Howdy Flinch-

50% reject rate is not normal - speaks to some kind of problem.

Give the higher melt temp a try as it is easy to do. If it solves the problem - you're home free.

If not - I would suspect insufficient venting of the mould may be the culprit. First - make sure your sprue plate is adjusted to be fairly loose. If it will almost swing from it's own weight - you are in the zone. If that doesn't do it get a machinists carbide scribe and use it to trace out the vent lines of the mould - especially around the base where you're having fill out problems. Be sure to trace it into the cavity to ensure you don't leave a burr in the vent line to block the air.

I have found venting to be wanting on quite a few commercial moulds and even some of the expensive custom ones. On a particularly stubborn Saeco .45-70 mould - I used the carbide scribe to cut 3 vent lines on the top surface of the mould under the sprue plate. These ran from base of the bullet cavity out to the edges of the mould. Cured the problem and casting went from <10% keepers to >90%. If you put the lines on the top face - be sure to lightly face the surface on a flat with some 400 grit or better wet/dry paper to be sure your sprue plate will be working against a smooth surface.

Good luck in tracking down the fill out problem.

Best regards-

Sky C.

Try continuing to pour after the mould is full. It may be that the base will fill out better if given more time for the air to escape. If you are using a bottom pour pot leave room between the spout and mould to vent any air.

Thanks to all that replied. Seems like great advice. I think the hotter melt temp may be the ticket because- of the good bullets that im getting, many are frosted with torn sprue holes on the bullet. When I slow down and let the sprue cool enough to cut clean the bases dont fill. Sprue holes on the bottom of the bullet is not a big problem so I wont worry too much about that anymore and lean more towards speeding up the process, hopefully this will cure the problem.
Sometimes we cant see the most obvious solution untill someone else points it out. Thanks again....Flinch

If you are using a bottom pour pot try pressure filling until the bullets are coming out frosted. If you are ladle pouring try puddleing the sprue as large as you can. Also loosen the sprue plat until it will move with the smallest pressure. Good luck and maybe one of the suggestions will help.

Thanks to all that replied. Seems like great advice. I think the hotter melt temp may be the ticket because- of the good bullets that im getting, many are frosted with torn sprue holes on the bullet. When I slow down and let the sprue cool enough to cut clean the bases dont fill. Sprue holes on the bottom of the bullet is not a big problem so I wont worry too much about that anymore and lean more towards speeding up the process, hopefully this will cure the problem.
Sometimes we cant see the most obvious solution untill someone else points it out. Thanks again....Flinch
Flinch,
I'm sorry,but sprue holes on the bottom of the bullet are a problem.That's why some Casters pay extra money for 'nose pour' moulds.
That ripped out hole is a void that will create an unbalanced bullet.
The only thing that I can add to the good advise that you already got,is to say that a toothpick will clean out the vents in the mould,with no chance of doing any damage.The steel pick will do it faster,if you have a steady hand (like I don't).

Hey there Flinch;
Man! You've gotten some great advice here. Since I can't tell from your comments, I can offer some other possobilitie that you may consider.
Poor fill out can also be the result of a contaminated lead source. As an example, lead scroungers, like myself,will in desperation use any source they can get there hands on. Lead shot from old salvaged shot shells will introduce far too much arsenic for good sharp edges if used in too great quantities. It's purpose is to aid the forming of nice ROUND balls by increasing the surface tension of the alloy.

Another taint is zink as found in many cast objects of novelty catagory. Aluminum will cause the same problems.

Look at some ( a dozen or more ) of your best production under a hand lens. Look at all of the edges that should be sharp. If you find consistant rounded edges throughout, you've got a bad batch of alloy.
I recommend the use of a lense cause a good alloy will produce sharpe corners. A tainted alloy can look almost o.k. with the naked eye.
I hope it's just a heat problem. Good luck
Pepe Ray

Thanks for all that great advice, way more then I expected. Im kinda new at casting so advice like this is like gold to me. I have read books but most of them just cover the basics, good enough to get started, but not enough info to be really good at casting high quality bullets consistantly. With all the tips from above im sure I can find the problem and fix it. Thanks again. Flinch

I have added lead free solder to increase the tin but havent noticed much difference in my # of rejects.

Flinch...

As always great advice listed above. I'm new to casting also but have cast several thousand of the C430-310-RF's for friends and my 444 and 44. I cast batches of both 50/50... LT/WW and 95/5... WW/Tin and have almost a "zero" rejection rate.

I was just wondering what that "lead free" solder was actually made from. May be it's "floating" to the top as you fill the mold and causing the problem. This is just a guess that something might be wrong with the "mix" as it seems some of the stuff in "lead-free" metals might not help casting. Really... just a guess on my part but something I would try before messing with the mold.

For my 95/5 bullets, I found solder with a 50/50... lead/tin ratio. I had to go to pretty great lengths to find it where I live as everything seems to be "lead-free". I took the time to do the math of what it would take to come up with that 95/5 mix by weighing a given length of solder, etc.

My last 100 casts with this mold had zero rejects except for the three I dropped on the floor. The WW bullets do take a little more heat to make pretty and it seems that the frosted look will come on at about 750...775... may be a bit more. The reason I've been frosting them is that Lee says their Liquid Alox will adhere better.

It would be neat to see just what a movement from "lead-free" to leaded solder would make with no change in your mold or technique.

Haven't found anything worng with lightly frosted bullets...know the grain structure is different and more coarse, but it hasn't shown any ill effects in use or accuracy. May let the liquid alox stick a bit better...give the bullet some "teeth"; never though much about that but it makes a kind of sense.

Don't think there is one right way to cast...seems that some molds just require difffernt techniques to get good bullets. The treasured ones are the few that cast well right from the start, drop their bullets on their own when the mold is opended with no tapping of the handles, and cast well over a wide range of temperatures and alloys...but they are rare. Others require "pressure casting" with the mold right up to the bottom pour pot's spout...others want a bit of distance betwen spout and mold...and a few just want to be dipper filled. Can go nuts trying to make a mold conform to your desies, or can just conform to its.

I think the lead free solder I was using was 95/5 tin antimony, but Im not exactly sure at the moment. I have cast without using any solder and got the same inconsistant results, so Im thinkin its more of a heat problem and possibly the sprue plate a little too tight. I wont have any time till this weekend to make more bullets as I have to make a living first. Thanks again for all the great advice.

I have been casting the lee 310gr gc bullet from wheelweights for my 44s and have been having some problems with the bases filling out. I have about 50% reject rate. (If the base doesnt fill out right then the gas check wont stay on). I have been fluxing with parifin wax but really havent noticed if it is helping or not. Im casting at about 700-750 degrees. I have added lead free solder to increase the tin but havent noticed much difference in my # of rejects. My question is, is 50% rejects a normal amount? and what tips can anyone give to cast more consistantly? Thanks....Flinch

I'm using the identical mold and found that I couldn't run temperatures anywhere near that. But it's probably not the same alloy. One thing I did find that might help you is don't plase the lead pot spigot in the sprue plate. You might let the allow pour freely. Also? let it set up a little before opening the mold. Even at the temps I was running you could throw before the lead has set up enough. And finally experiment with the temperature.
I backed off from 625-650 to about 525-550. Although that's just a reference from the pot indicator, I'd need a thermometer to really know what the actual temp was.

Well, I think I am almost there. I used more heat today (about 775-800), loosend the sprue plate a little more, poured bigger sprues, and had much better results.
I also found that if I fill the cavities faster instead of pouring slow (bottom pour ladel) it seemed to fill out better. Maybe because it is not losing as much heat in the process, or maybe because its filling with more pressure. I have a bottom pour ladel and was thinking about drilling the hole out a little bigger so it will fill the mold quicker. Anyone else find that the rate of pour effects bullet quality? Or am I way off base with this theory? Thanks...Flinch

Flinch- I opened the spout of my Lyman dipper up a little bit, and it did help some. When I pour a bullet, I treat it like 2 single cavities. I pour one bullet, and keep pouring over that cavity until I empty the dipper. I then refill the dipper and do the same for the second cavity. My reasoning- by continuing to pour lead over the mould after the cavity is filled, I keep the base of that bullet hot a little while longer. This, in my mind, allows air more time to escape, and pressurizes the base a bit to force air out. Whatever actually happens, it works very well for me. I've never gotten more consistent high quality bullets than I do with this procedure. I've found that if I try to fill both cavities with one dipper, the second bullet usually has rounded bases, and poor fill out. Also, by the time I get to the second cavity, the alloy in the ladle has cooled a bit, and that can be bad for bullet quality too. I have several 4 cavity moulds, and cast one cavity at a time with them too. It takes more time, but much less time than remelting rejects, and re-casting them. One other thing, if you're ripping holes in your bullet bases when cutting the sprue, you'll need to let the mould cool a bit longer before cutting the sprue. I usually cast with 2-3 moulds at a time to make certain I don't rush things too much. If you only have the one mould, try resting it on bullet metal ingots to act as a heat sink, and speed the freezing process. It really works well when you cast at higher temps. ==bob

Thanks bob, I will try filling each cavity like that and see if it helps. It makes sense that if the base stays hot longer it might fill out better. Worth a try. Quality is more important to me then quantity.