Help me figure out my problem

[dbarnhart]

First session today with the new Accurate 45-230M mold. I'm getting two problems as you can see form this photo:
http://www.shootandreload.com/wp-content/uploads/2012/01/DSCN0117.jpg

1. The boolit on the left is from the rear cavity and has a nice sharp trailing edge. The boolit on the right is from the front cavity and has a rounded trailing edge. I'm getting this result consistently.

2. I think I'm waiting too long to cut the sprue because as you can see, when the sprue us cut it takes a small chuck of lead from the trailing side with it.

What do I need to do to correct these problems?

[jim 44-40]

I think you need to feed the mold longer with the ladle. Hold it after you rotate the mold a few seconds,and make sure you have a good puddle of lead on the spure plate when you finish.Hope it helps

[canyon-ghost]

When one cavity pours differently like that, it's too cold. Your mold is on the verge of being too cold when poured. Pour both cavities full and hold for 30 seconds, at least 15 seconds. It lets the heat go into the mold and evens up the cavities.

I can almost bet that you fill the back cavity first sometimes, if not, then you've let the front one cool. Keep that mold closed as much as possible to heat it. If you get too much frost and heat, all you have to do is leave it open and wave it through the air once, then close and pour.

Tin can help fillout but, 90% of the time, it's how you pour!

Good Luck
Ron

[canyon-ghost]

2. I think I'm waiting too long to cut the sprue because as you can see, when the sprue us cut it takes a small chuck of lead from the trailing side with it.



Wrong, you're cutting it when it's hot, wait longer and it will shear instead of tearing out! You've just got to see it happen a thousand times. Bullet base is too hot in the photos. Let 'er cool down longer.

[Danderdude]

Your mold is too cold. Put it on a hotplate or in a toaster oven while you wait for the lead pot to heat up. I set my toaster oven to 450 and leave the door open a bit so the handles hang out.

The other thing is you aren't pooling the lead on top of the sprue plate. You need to have liquid lead sit on top of the sprue so it runs in and fills the base of the cavity. That's where your rounded problems are coming from. Once the mold is hotter, it's easier to pool the lead. Also, once your mold is hotter you can run cooler lead and reduce the frosting.

[Wayne Smith]

You have good advice here. Is this an aluminum or brass mold? They heat very differently.

If you have addressed all the above suggestions and still have the problem look at the venting for that cavity. If the air can't get out the lead can't get in.

[dbarnhart]

It is a brass mold from Tom at Accurate

[Larry Gibson]

It is a brass mold from Tom at Accurate

What alloy are you using?

What temp is the alloy when casting?

Larry Gibson

[dbarnhart]

The lead is a 50-50 mix of WW and range lead with about 1% extra tin added by me. The temp of the molten lead is 700 degrees. This is the same lead I was using with an aluminum Lee mold abuot a week ago.

[geargnasher]

Alloy's fine.

Judging by the heavy frost, I think the mould is actually a bit too hot.

The fillout issues, I believe, are mostly due to pour technique and excessive sprue plate temperature.

Tom's moulds don't really vent. They have some light mill grooves on the block faces, but they don't serve to vent. The sprue plates are polished and fit square, and even if the top mating edge of the blocks is beveled slightly (I think Tom does this to all of his moulds now), the moulds simply lock up so tight, fit so well, and have such reliable alignment points that they need to vent mostly out the sprue hole.

The key is to "swirl pour", where you drop the alloy at either the right or left edge of the sprue hole, and tilt the mould either down or up in front a few degrees so the stream hits the side of the nose part of the cavity at an angle, like the angle of the rifling in a gun barrel. This will cause a vortex inside the mould with the alloy spiraling in one way and pushing superheated air out the other way. This superheated air actually has some inertia, and when the alloy nears the top the moving column of air will create an ever-so-slight vacuum that helps purge the mould and clear the base of air.

You also need to fill the cavities QUICKLY, don't dribble alloy in there. Dribbling alloy or a weak stream is a sure recipe for rounded bases.

Also, if the cavity that fills poorly is the last one you pour every time, that indicates you aren't pouring in a way that allows the mould to vent. The first one can vent down the mating line right under the sprue plate both directions, but with one cavity full, the next only has one avenue to vent. You can increase this bevel some with a fine file, but don't overdo it or you'll have spikes on your boolit bases.

Gear

[runfiverun]

sprue plate tension.
cut the sprue a second later.

[dbarnhart]

The second casting session with the Accurate 45-230M went much better.

I took geargnasher's advice and started using a 'swirl pour'. I also let the sprue cool a bit longer (long 5 count) before cutting it. When I started getting the rounded edges on boolits from the front cavity I opened the mold and let it cool for a few seconds and that seemed to do the trick. SO the mold is definitely getting too hot.

Perhaps I'm trying to move too fast. I'm using a bottom pour Lee pot. When both of the mold's cavities are full I'm waiting what seems like 6 or 7 seconds before I cut the sprue. Then I open the mold dump the boolits, close the mold, and do the next pour.

Also, I was a little more careful this time when I measured the temperature of the melt. It was actually 725.

[Larry Gibson]

Yes, the alloy would appear to be ok. Don't smoke the cavities. Slow down a bit on the casting. You might try using the two moulds together casting alternately between the two, keeps the moulds cooler that way and you'd be surprised how many bullets you can crank out with 2 cavity moulds.

Larry Gibson

[Recluse]

Alloy's fine.

Judging by the heavy frost, I think the mould is actually a bit too hot.

The fillout issues, I believe, are mostly due to pour technique and excessive sprue plate temperature.

You also need to fill the cavities QUICKLY, don't dribble alloy in there. Dribbling alloy or a weak stream is a sure recipe for rounded bases.

Gear


sprue plate tension.
cut the sprue a second later.

+1

I keep a very wet, almost soaking/dripping wet folded towel on a ceramic tile to the left of my pot and use it to help control the temp of the primarily the sprue plate, but also the mold itself if I get to casting too fast--especially with larger boolits.

:coffee:

[stubshaft]

The only thing that I would add is to alternate between front and rear cavities to keep the mold heat consistent.

[dbarnhart]

My third casting session with my new Accurate mold went very well and I am very pleased:

http://www.shootandreload.com/wp-content/uploads/2012/02/DSCN0123.jpg

I bought a hotplate from Target for $16 and used that to heat the mold. I took stubshaft's advice and alternated the first pour between the front and rear cavities, and geargnasher's advice about doing a 'swirl pour'

I had very few culls this time.
I can't thank you guys enough for all the help you've given me. I would never have even attempted it without you guys.

Part of my glee comes from knowing how little money I've spent. I bought a Lee bottom-pour pot, thermometer, and RCBS ingot mold off another caster for $16. The Lee lub/sizing kit was $19. The most expensive thing was tom's mold and it was well worth it.

Even with buying ingotized WW, I'm reloading 45 acp for $3.45 per box.

[geargnasher]

Good job!

Gear

[runfiverun]

those look good..