Frosted But not Filled Out

[megasupermagnum]

I think the key statement that explains what's going on here was that if the pour rate is increased the lead just overflows the sprue plate. If the molds are up to temperature, and the alloy is being cast hot enough that there's frosting, and there still isn't proper filling, this seems to indicate that there isn't enough venting in the mold blocks to allow full fill out. If this is the case, increasing both the lead and mold temperature will have no effect. Also, changing the alloy composition may have little or no effect. Check that the vent lines inside the mold block aren't clogged. For the lead to fill the mold the air inside the cavities needs to be able to escape. It could be your alloy, but check for the simpler solution first.

I agree. While the others advocating tin are not wrong, I just don't see that as a real fix. I cast a wide variety of alloys including pure lead. All alloys, or pure lead can be cast to complete satisfaction if your technique is good. Tin does help reduce surface tension which does seem to make fill out easier, but it still wont overcome more than a minor problem.

Sprue plate temp is a factor for the base of the bullets, but I've not seen it effect the rest of the bullet. It is worth noting that I have seen sprue plate temp cause issues of only one side of a bullet base filling out, however, the rest of the bullet is filled out well. That is generally from too cold a sprue plate which solidifies the lead in that spot before the other side. To combat that, I often alternate which end of the mold I start pouring into each cycle.

I would still be looking at fill rate or venting first. You say that it is already filling so fast that lead would splash out if you went any faster. That could indicate your mold is not venting well. It could also indicate you happen to have a pot that can flow a lot faster than most. It's really hard to critique your method without being there. A picture would help us a lot.

[Bazoo]

Mould filling rate is not all the indicators. Where the mould cools down is after you drop the bullets, but before you pour the cavities again. So, If you are going to do something like, look through your bullets, do so with the cavities full, but cut the sprue before you pause a few seconds. I can do this maybe 30 seconds and keep the mould to temp.

[GregLaROCHE]

No tin, just straight wheel weights.

I do clean my molds with 99% alcohol before I cast with them.

Alcohol is not the best degreaser. I clean mine with brake cleaner and then dish soap before using each time, because I always spray the down with Ballistol fêter use.

Try the fastest fill rate you can keep up with.

[Sasquatch-1]

Rounded bands.

What's the best source of tin? Or, maybe the least expensive source?

Old solder and Pewter are probably the easiest to find. When yard sale season is in full swing you may be able to find both at yard sales and flea markets. You may be able to find pewter at thrift stores, but watch the price, I think the thrift stores are catching on.

[Bazoo]

I got some tin from the site here, I'm getting low , so I'll be trying to find some more soon.

I clean my moulds with lighter fuel. When the mould is good and hot, but not all the way to casting temperature, I open the sprue cutter and fill the cavity with lighter fuel. It boils in the cavities and that really helps to scrub the nooks and crannies clean. I have never had it burst into flames doing this, even if the mould is very hot. In that case, it sorta evaporates or skates off the surface rather than collecting in the cavities to boil. It works like a charm. I believe I am the originator of the technique too!

[jdgabbard]

I've cast from straight WW (mixed not separated) and didn't have any issues with fillout. I've also cast from 99% pure without any issues. This isn't a tin problem, althought that MIGHT help. It's either a mold problem, or your mold is too cold. Tin could help with fillout. But you could also try pressure casing them by pressing the nozzle up to the sprue hole or using a ladle. But that is generally something that is done with large boolits that have a problem with fillout. This isn't normally the case for pistol size boolits. You might also try fluxing really well, as I've found dirty and/or alloys with oxidation fragments down into the melt cause problems with fillout as well.

Venting might help, I would definitely look at the mold halves to see what is going on with them. If everything is fine, it sounds like you might just need to speed up your casting rhythm. Assuming you poor is fast enough that is. Your poor shouldn't take much more than a second or maybe two for larger molds. Most of the time I have to zip from one hole to the next because I have my poor set to a very fast fill, and I always leave a very large puddle on the sprue plate - i.e. covering 2/3 to 3/4 of the plate.

I'm thinking this is a learning curve situation...

[WRideout]

A mold that has seen a lot of use can build up crud in the vent lines, and show poor fillout. Just for completeness, I would give the vent lines a once over with something like a bamboo skewer. The suggestion to leave a large sprue puddle is right on.

Wayne

[TXTad]

A mold that has seen a lot of use can build up crud in the vent lines, and show poor fillout. Just for completeness, I would give the vent lines a once over with something like a bamboo skewer. The suggestion to leave a large sprue puddle is right on.

Wayne

I'm going to get the mold as clean as I can with degreaser, make sure the vent-lines are good, cool the lead just a bit, and make darn sure the mold is hot.

I do leave the big puddle because not only is it good for the process, it's easier to pick up the bigger pieces when it's time to drop them back into the pot.

[Bazoo]

I have found that I get better success when using beeswax to flux with vs paraffin or sawdust. I know from a scientific standpoint sawdust is great. But from a "how the alloy acts" perspective, beeswax does better.

For mould heat, I generally dip the ladle corner in the lead, and I try to get the sprue plate in there too. I use a rubber band on the handles to keep the halves from opening. I then read a bit in a book I keep handy. After about 5-10 minutes, we have a hot mould. The first several casts will be too hot and frosted, I just slow it down some and then I am where I need to be. I suspect, but I don't have a way to check, that the mould temperature will have a gradient across its sections. And you could still have some parts that are too cold when the rest is up to temperature.

I know the handles suck heat. I generally start by heating my handles separately, give them a while, and then attach them to the cold mould, then give the mould that long corner dip.

Right now I'm working on a book that is a collection of adventure stories by the way, before that it was Tom Sawyer. So for me, it isn't as waste of time to wait a few minutes more..... I rather enjoy it.

[Professor]

I have a bunch of lee molds. None get used anymore but I made a lot of bad bullets with them. I learned to appreciate a quality mold because of all the time I spent with the lees. Only one that ever cast a full size bullet was 250 grain 45 rnfp but they weighed a varuzble of 10+or- grains. I shot a lot of them. My mp molds usually cast with a grain.with my range scrap wheel weight mix. Powder coated they run excellent. I think the lee molds are just too thin and small. They don't wear you out. But they overheat quickly, get too loose, the sprue plate comes loose. Just too problematic. But they work if you just need something to put in the dirt.

[JonB_in_Glencoe]

Professor,
Welcome to the forum.

"put in the dirt"
tell us what you really think of Lee

[pcmacd]

Hot Lead, cold mold

Agreed. Keep casting them rapidly w/o inspection for five or ten cycles, then have a look at the last cast.

[gmsharps]

A lot of good ideas have been posted here. Just another thing to try is the angle you are holding the mold when casting. Sometimes a mold requires a slight tilt one way or another to completely fill properly. Sometimes that is caused from a clogged fill line not letting the air to escape and tilting can aid that a bit. Some molds require different techniques. You just have to figure out yours.

gmsharps

[pcmacd]

Alcohol is not the best degreaser. I clean mine with brake cleaner and then dish soap before using each time, because I always spray the down with Ballistol fêter use.

Try the fastest fill rate you can keep up with.

The most aggressive cleaner I have, I got from Magma Engineering decades ago. It is similar to Cascade dishwasher soap in that both are highly caustic. Tablespoon in cup of hot water, soak mold for a while, scrub with toothbrush, rinse, repeat if required. Wear rubber gloves and eye protection. Put into production immediately, heat soaking the mold atop the pot to dry it well first. Or put it in a 180F oven for a half hour. Spray with lock grade pure graphite to both condition and protect the mold when it is well dried out.

I would not use this stuff on anything but a cast iron mold, as I am sure it would eat an aluminum one.

[pcmacd]

A lot of good ideas have been posted here. Just another thing to try is the angle you are holding the mold when casting. Sometimes a mold requires a slight tilt one way or another to completely fill properly. Sometimes that is caused from a clogged fill line not letting the air to escape and tilting can aid that a bit. Some molds require different techniques. You just have to figure out yours.

gmsharps

I have a LEE mold where if I don't put the lead stream down the side of the sprue hole, it jets back out all over the place and makes otherwise truly ****ty bullets. Took a while to figure that one out.