need a little help.

[jimb16]

I'm running into a problem that I haven't experienced before. I was casting a batch of 45 gr .225 boolits yesterday. I had around 50% rejects. The problem was the bases. The boolits were well formed with the bands nicely filled out. The surface was clean with no visible flaws. There were no visible holes on the bases. BUT The bases themselves were uneven and many had rounded edges. I turned up the heat, but that didn't seem to help. I slightly loosened the sprue plate and I started to get fins, but that didn't help either. (fins on one side and rounded edges on the other.) I cleaned the mold. I scrubbed the surface of the mold and the plate with steel wool to make sure there wasn't any lead sticking to the surface. I lightly stoned for rough edges. (The boolits drop free.) I just can't figure out why the bases aren't filling completely. Any Ideas?

[OutHuntn84]

Did you try varrying how much sprue you poured while casting. I have a mold that doesnt cut the sprues as clean when I poor too light. Not sure what vodo witch craft causes it to be that way but it does. Try pouring faster and leave a heavier sprue.

[repawn]

I am no expert but I was told a little more tin helps - that is what I did and it worked for me.

[chboats]

Pouring a heavier sprue, as OutHuntn84 said, usually fixes my rounded edges. If that does not work try pressure casting.

Carl

[jimb16]

I tried more tin...didn't help. Wax fluxing didn't help. Pressure casting didn't help. Heavy sprue didn't help. Higher temp didn't help. Faster pour didn't help. I've been casting for more than 40 years so I know all of the usual fixes. This one has me scratching my head. I even tried the mold hot enough that I had to wait for the metal to solidify so it wasn't mold temp either.

[ku4hx]

Pictures might help.

[44man]

I never depend on a boolit taking lead from the sprue. I feed molten lead from my ladle until the boolit is full. Tipping off a good sprue shows almost no sprue shrinkage, only what the sprue itself shrinks.
The outer edges of the boolit set first and drawing from the sprue only goes to the center under the hole. It can't flow to the edges. Better to keep the whole base molten as you feed lead.

[jimb16]

Can't do pics as the rejects have already been remelted. I guess about the only thing that I haven't tried is filling from a ladle. But I would think filling under pressure from a bottom feed pot would be better. I guess I'll give it a try anyway.

[lka]

Did you clean the back of the spruce plate? Try putting a Torch to the back side for a sec, it will burn off any oil that may have got back there.

[Pilgrim]

I don't think ladle vs. pot will give you your answer. For some reason, the area around the base isn't venting properly. Have you tried pouring off-center and also dead centered into the mould opening to see if one method works? One suggestion is to smoke the base of the sprue plate and the top of the mould. This might delay melt set up long enuf for the base to completely fill out. It also might help ( why? Dunno why. Maybe just because?) with venting. You didn't mention if this is the 1st time you've cast with this mould. If it worked before, what could be different? Sorta flummoxed, too! Pilgrim

[runfiverun]

try just dribbling the lead into the cavity.
you have a venting deal going on.

[41 mag fan]

What RFR said sounds like the problem. I had a couple of molds that would give rounded uneven bases. Took me some time to figure out, but if I dribble, not pour fast and use a almost pressure pour system where the spout is resting on the beveled edge of the sprue hole, it does a dribble swirl effect, that filled my bases out. Worked for me and got what I needed it to do and that was fill my bases out.

[country gent]

With a sharp scribe clean the vent lines at the upper half of the mold. Do this with a very light hand. You only want to remove the possible build up not any metal. Some times the waxes lubes used on the mold will give a build up in the vent lines. Sounds like they may have a build up in some of them. Getting the air out quickly and easily will help alot. I have found this to help alot at times. Usually the last couple lines will also affect the bases. Pourous metal molds ( cast iron, some aluminum) can be a pain to get things burnt out of, think a cast iron frying pan used for cooking. SOunds like a venting issue more so to me though.

[jimb16]

Sprue plate is clean. Even went over it with steel wool after heating and wiping clean. I'll try resmoking the mold and cleaning vents. That is about the only thing that I haven't done. I tried the dribble and swirl fill techniques. Those didn't help either. And yes, this is the first time I've used the mold. I inherited it from my F-I-Law after he died.

[runfiverun]

you could try loosening the sprue plate.
taking a stone to the edges of the mold and lightly [3-4 passes] making an angle there.
this will help vent air also.

[41 mag fan]

Have you tried fast flow, pressure casting? Or even pressure casting with the flow rate you was using?

[Big_Blue]

Could it be the lead? Do you know that the mix of alloys is correct?

[NoZombies]

Casting little bullets can be tricky. Almost every time I have ever had a small diameter mold that didn't want to fill the bases, it has turned out to be a venting problem.

It has already been said, but there are three common and easy fixes to this problem, in order of simplicity:

1. Loosen sprue plate.
2. Clean venting lines at top of mold.
3. Extremely small radius at top of mold block where cavities meet. (a few strokes carefully with a hard and fine wet stone is all that's needed)

[jimb16]

At this point I'm pretty sure that it is the mold. I have a second identical mold. I started casting with that one and got as near perfect bullets as you can ever hope for.(rejection rate around 3%!) I'm going to inspect that bad mold with a magnifying glass and see if I can figure out what is going on. The mold is a Lyman 225415. The bullets cast are .001 out of round and have a max of .225 dia. The other mold is almost perfectly round and cast at .2245. (two mics and a caliper all agree on these) And another question...I have another mold marked 225415CP. It appear to be a similar design, but is longer and casts at about 63 gr. Anyone have any info on this mold?