Casting Trouble

[Danth]

Hello All: I have a 4 cavity adjustable core mold. It's the type with a large reservoir on the sprue cutter. i have cast thousands of cores, but one cavity will not fill. I've tried pouring in different locations on the sprue cutter reservoir, adjusted pour rates, tilted the mold so that cavity would fill 1st and last. I've cleaned the cavity, lubricated the cavity, checked for obstructions (burrs, etc.) sanded around the opening and nothing seems to work. Any suggestions? Thanks, Danth

[Lizard333]

Do you preheat the mold prior to casting? Maybe that mold needs a little more heat.

[sparky45]

Probably needs to run hotter.

[dragonrider]

It's a venting problem

[runfiverun]

yessir it is a venting issue.
it's a core mold.
just make it a little deeper/heavier and squirt the excess.

[Danth]

This mold is not vented. It consists of four independent cylinders with plungers in each to adjust the depth of the cavity. I use Hollywood swage dies which do not utilize a squirt die, so it's important to get each core as close to finish dimensions as possible. The excess lead is squirted thru the bullet nose, so excessive lead becomes problematic if there is too much. This could be a heat issue but varying the set point on the lee bottom pour furnace hasn't fixed the problem.

[Danth]

Problem solved. Don't know why, but loosening the sprue cutter allows the problematic cavity to fill. Perhaps this effects venting, but that was the problem. Thanks to all that responded to my original post.