Vibrating, Shaking Mold While Pouring

[darne]

If this belongs in the equipment section please move.

I have searched and only came up with a few hits about hollow points.

The question is; do you shake or jiggle the mold as you are filling the cavities?

I am casting .432 240 gr from a Mountain Molds three cavity. My other Mountan Mold is a two cavity and I was succesful holding the sprue plate tight to the spout of my RCBS furnace. The three hole has the groove connecting the sprue holes and a little lead spurts out right into #3, so I've been running it on the mold support bar. I've been shaking the mold by hand as I cast and the quality is much higher with fewer rejects.

That has got me thinking about a mechanical vibrator for my casting booth. My conceptual design is a washing machine motor mounted on the underside of the floor of my cabinet with a 6" bar bolted to the shaft and an ingot on the end of the shaft sort of like a big vibraory tumbler to shake the furnace and mold so I can concentrate on the other stuff going on.

Have any of you tried something like this?

[HeavyMetal]

When casting HP's in a single cavity mold I get everything hot enough that the alloy stays liquid long enough for me to shake the mold with the ladle in contact wih the sprue plate.

Haven't been able to prove to myself this does anything more than just leaving the ladle in contact with the sprue plate alone does.

I have found that keeping the sprue plate hot has reduced rounded bases in all my molds not just the HP ones.

Now I think your on the right track with your problem but seeing the wrong "solution".

What I am doing ( someday) is building a mold guide that has a roller bearing on it and set up so I can place my mold under the pot at an angle ( front to back, back being the lowest point)

The idea is to fill the rear cavity first then pull the mold to you at an angle making the sprue puddle "climb" up the sprue plate while pouring.

I have been doing this with my Lee 6 bangers and it makes a huge difference with fill control.

The guide would be nothing more than an "L" shaped piece of metal with a "roller" made from 3/8's scrap round stock held on with an e clip and then mounted upside down under the spout!

Haven't decided if I'll mount mine to pull the mold straight back or if I'll try to go sideways with the mold.

[jbunny]

darne; take a look at casting zinc boolits and i have a pic of a mould vibrator
useing a scrap hair clipper. it works like a hot dam.
regards
jb

[JSnover]

A good friend of mine told me about shaking the mold. Claimed it was pretty common to find bubbles. It can't be too difficult to hook up an old clipper or electric razor to the underside of the mold guide.

[beagle]

I'm thinking the bullet will harden before you get it on a vibrator unless you cast with it resting against a vibrator.

As has been stated...plenty of heat casting HPs is the key. Got to keep 'em hot.

As for vibrators, I think the bullets set up too fast. All of our cast bullets have voids in them. Now, I'll get shot at verbally for this statement but it's true.

My old shooting partner (deceased) got on a moly plating kick and used moly mixed with jeweler's media which is scrap metal. It impact coated the bullet beautifully but it also exposed the voids. Now, neither of us were rookie casters having been in the business for many, many years.

I knew about base voids and was aware of how they formed, etc. What I wasn't aware of was the other voids which occurred on the bands, in the lube grooves and on the ogives.

Nearly every .30 bullet we moly coated had voids and we culled the worst and selected the bullets and he got some fantastic groups.

He was a dipper man and I was a bottom pour man and it seemed to make little difference in the method. We still got the same amount of voids.

But, be aware of this phenomonen in cast. /beagle

[jbunny]

A good friend of mine told me about shaking the mold. Claimed it was pretty common to find bubbles. It can't be too difficult to hook up an old clipper or electric razor to the underside of the mold guide.
casting with zinc and zinc alloys, a vibrator IMHO is a must. when i'm useing
WW aloy in my bottom pour i have a bolck of wood that i tap the base of the mould on
this fills the base completely. as for mounting a vibrator on the mould guide on a bottom pour, i would be leary as i think it would cause premature failer of your
furnace.
regards
jb

[Marlin Hunter]

I lightly tap the mold with the wooden dowel I use to open the sprue plate. I do it while the sprue is still molten liquid.

[runfiverun]

i shake the mold as i fill it using the welders shake.
and a tap on the bench as i move the mold.
it can't hurt none.

[Le Loup Solitaire]

An older practice/trick used by some was to gently drop the filled mold several inches down onto a lead ingot or block of 2x4 with the sprue puddle still liquid so that the blocks were jarred. Not hard enough to cause the sprue to slop up and out/off the plate, but to get the inertia to drive the melt into the base of the bullet and help eliminate voids and/or bubbles. LLS

[JSnover]

casting with zinc and zinc alloys, a vibrator IMHO is a must. when i'm useing
WW aloy in my bottom pour i have a bolck of wood that i tap the base of the mould on
this fills the base completely. as for mounting a vibrator on the mould guide on a bottom pour, i would be leary as i think it would cause premature failer of your
furnace.
regards
jb

With some of the bigger clppers, yeah, you could be right. Lately I'm thinking about sacrificing one of those newfangled vibrating razor handles. It might jiggle the mold just enough without disturbing the structure of the pot. Or I could just tap the side of the mold lightly with a stick. Makes more sense, sticks being free and all....

[EMC45]

I lightly tap the mold with the wooden dowel I use to open the sprue plate. I do it while the sprue is still molten liquid.

I do this frequently as well!