One problem solved - another crops up

[captaint]

Saturday I got one of them hot plates. Was doing a little casting yesterday, preheating the mold solved the wrinkle problem - great. Later when sorting thru the boolits I notice the driving band is not always filled out. Some boolits have nice square front of band on one side and rounded on the other. Some have rounded band all around. Is this a "mold not hot enough" deal also, or am I doing something else wrong. I'm casting 45acp 200 gr swc's. Help again!:Fire:

[redneckdan]

whats your alloy? As far as heat, I cast fast enough and hot enough that the boolits start to frost a little bit. The .429 HBWC mould that I have requires 2% tin added to range scrap in order to get good fill out, no matter how hot I get the mould. Casting range scrap with my RCBS 45-201-SWC, I crank the pot up and cast fast and get decent fill out. Not text book perfect but usually I get crisp edges. I have to force cool the sprue plate in order to prevent smearing on the blocks.

[Echo]

A little tin goes a long way. It reduces the surface tension of the molten alloy, allowing it to completely fill the mold. Many folks advocate turning the heat way up to enhance mold fill-out. I would rather cast a little cooler - it reduces oxidation and therefore the need for continuous fluxing. Still, a frosted boolit isn't a bad boolit. Find some solder and add to the pot. Two percent is enough, anything over 3% is wasteful. AND DON'T USE ACID CORE! Lead-free solder is practically pure tin, and is available from Grainger, or even Ace or Tru-Value.

[AZ-Stew]

If the tin doesn't work, try a slightly faster pour.

Regards,

Stew

[captaint]

Alrighty then, we'll try a little tin. I have some, only it's in 5lb ingots - I'll think of something to cut it up. Thanks again for the help.

[NVcurmudgeon]

Besides the worthy suggestion of others to add 2% tin, try running your pot a little cooler. Frost is good, but overdone it can lead to what the Mountain Moulds man calls "shrunken band syndrome." Been there, scratched my head over that.

[44man]

Besides the worthy suggestion of others to add 2% tin, try running your pot a little cooler. Frost is good, but overdone it can lead to what the Mountain Moulds man calls "shrunken band syndrome." Been there, scratched my head over that.
Exactly, too hot is no good either. A slight frost is OK or just under for shiny boolits.
However Captaint did not explain how he is casting either. Bottom pour or ladle, temperatures, etc.

[leftiye]

Some alloys cast better than others. And some alloys therefore are a headache to cast. Sometimes it needs tin, and sometimes it needs more heat, and sometimes it's just a pain. Don't be afraid of more and more heat - until you are getting frosting - then back off. Dirty molds cause this kind of problem too, and unseasoned (not having an oxide layer developed) molds also cause perschnicketies. Sometimes a mold release will insulate the surface, and help fillout - DON'T gobb it on! Too much obscures the features of the mold (can you say deformation?).

[captaint]

Using a bottom pour pro melt. The temp was according to the dial, between 700 & 750. I'm also using a 2 cav steel mold, pouring relatively quickly, for me at least. Just ordered a thermometer today from Rotometals - 39 bucks + 10 shipping. Not real bad, be nice to have one tho.

[44man]

Play with the flow into the mold. You might be dumping lead in faster then the vents can clear air out.

[Baron von Trollwhack]

Sometimes it is as simple as properly enlarging the sprue holes in the plate and carefully tapering them. A lot is technique too. BvT

[Trapshooter]

I have had some problems with uneven band fill out if the mold is held too far from the spout on a bottom pour furnace, Raising the mold closer to the spout has cured a number of problems for me, without fooling with alloy or pot temperature.

Trapshooter

[runfiverun]

i think 44 man has it.
pour a tad slower,tyr hitting off to the side of the hole so the lead swirls in.
you might also need to watch for the suck-in of the alloy from the sprue puddle.
i have a 44 mold like that .if i don't wait for it, i might as well not use it.
if all you got is 5 lb chunks. throw one in a pot then drain out the pot into ingots the same size as you can make them.
then you have diluted them down,you can figure out how many you need to mix a pot.
ie if you get 20 ingots from the pot you have 1 lb in 4 ingots or use 1 per 20 lb pot
mixed with ww's will give you close enough to 2% .with range scrap your guess is as good as anyones. but it will give you enough.

[Bret4207]

I'm playing with a bottom pour now. I see all sorts of different issues than I get with the old reliable ladle. With that in mind I'd like to add that there is a huge difference between alloy temp and mould temp. You can have your alloy glowing hot and the mould can still be too cool if it takes too long between fills. Think about that- you get the mould hot by filling it fast time after time. The hot plate helps, but alloy heats it from the inside out and gets the sprue plate hot too. There's no sub for it in my book. I like a nice even frost on my boolits and I haven't observed any shrunken bands , yet! Now I'll have to look for them.

Also remember that venting changes with temp. I'm not a fan of the moulds we see where some clown took a hacksaw to it to "add some venting", but a tiny prick punch or scriber can be used to open up some venting. Something as simple as lightly dragging a knife blade along a vent line can work. And of course with Lee moulds the vents are sometimes completely blocked from the maker.

Just something to consider.

[captaint]

Wow - now I've got some clues. Like the idea of melting down the tin into smaller ingot size. The RCBS ingots I have now make about 1lb ww. Thanks again, all. Mike