Dumping the Sprue

[Barn]

I was wondering if anyone else dumps the sprue when casting?

I use a bottom pour furnace. I have a pan setting between the furnace and me for the sprue cutoffs. I like to pour a large sprue puddle. I fill the mould and then move it over the cutoff pan. I then tilt the mould down and to the right about 15 degrees dumping the excess sprue. The remaining sprue will start to setup almost immediately. After the color change and shrinkage have stopped I dump the bullet and start over again.

I find that this is faster than waiting for the large sprue puddle to harden. By the time I dump the sprue the puddle has done its thing for fill out.

I have only used this procedure for single and double cavity moulds with 30 caliber rifle bullets and 357 caliber pistol bullets. Not sure how it would work with multiple cavities or big bullets.

 

[JSH]

Nope.
I run two molds at times just so the cavity draws all it wants. Plus letting it set keeps smears to a minimum.
I also like a large puddle on my sprue. Pretty bad casting with my old single cavity 225415, my sprue probably out weighs my casting!
I have also done the sardine can with a damp sponge or rag to help cool the sprue. That has become a last resort anymore, unless I just have some kind of stubborn issue with running my pot hotter than I like too.

 

[Brad]

I use a ladle so extra lead runs off and back into the pot. I still get a small sprue.

You are using the sprue dump to actually dump some heat.

I ask this- are bullets well filled out and consistant in dimensions and weight? If it works then don't mess with it.

 

[RicinYakima]

Casting bullets is an art form (don't beat me up yet, I still believe it!). If it works for you, it is a great technique.

 

[Brad]

Ric, I agree entirely. The art is in being able to see what is happening and know how to alter it. Some is a lifetime of learning what the right look or feel is.

 

[KHornet]

No two casters are the same, and what works well for one many not be what works
well for another. As the old yankee saying goes: "If it works, don't fix it"

Paul

 

[JonB]

I pour as large a sprue as possible, and don't dump any molten alloy off the mold.
Actually, I learned this 4 years after I started casting...it has solved a fillout problem, which I call shrinkage, that I mostly got with long skinny rifle bullets, but I did see it in other molds as well. The molten sprue is basically a reservoir of alloy for the bullet, as it freezes (and shrinks)...if it doesn't have the reservoir, it has no molten alloy to 'pull' into the mold to keep the bullet from shrinking.

I posted about my saga of my shrinkage problem here.
http://castboolits.gunloads.com/sho...nkage-announcing-the-solution-(for-me-anyway)

Now, with my opinion aside...and as others have said, if it works for you, and you get well filled out bullets, no doubt your technique is working for your setup/molds.

 

[Ian]

I pour as large a sprue as possible, and don't dump any molten alloy off the mold.

When bottom-pouring, I do exactly this. It makes less of a mess and keeps the sprue plate nice and hot. Often, the mould blocks need a little time to cool off a titch so the bullets drop free, and waiting for a big sprue puddle to flash over and firm up enough to cut without smearing is a good way to kill time and keep cadence. The size of the puddle and overall pace can be worked around to keep the sprue plate and block temperatures in a happy zone.

 

[Pistolero]

What Ian said.

 

[shootnlead]

I find that handling the sprue kind of varies depending on the mold that I am using...but it is typically the same, leave it all on until it is time.

 

[Creeker]

I pour enough sprue but not excessive & allow it to harden on the plate.

 

[Cherokee]

Same as Creeker

 

[KHornet]

I cast as fast and as hot as possible, which is based on the first signs of hardening of the
sprew. Am also a firm believer in Bullplate.

Paul