Bullets collapse on one side

[Gohon]

Not sure if I can explain this enough but I just received a new Lee 2 cavity mold which is a TL/SWC. When casting the inner cavity drops a cast with a collapsed section on the side facing the the other cavity. The collapsed section, about 1/4 inch diameter and maybe .004-.006 deep is also frosty where as the rest of the bullet is bright in color. I tried temperatures from 650 to 800 degrees with no results. I also used a damp rag to cool the mold in between casts as well as running the mold hotter. Nothing works. The outer cavity drops perfect bullets. Only thing I can think of is a venting problem. I have several Lee molds but none of them act like this. Any ideas?

[geargnasher]

Sounds like a venting issue, with a trapped air bubble collapsing when the boolit cools. I don't get what you mean by "inner cavity" unless you mean the one closest to the handles. If that's the one that's doing it, check your sprue plate for being too tight, and try pouring that hole first. Also, check out the sticky in the mould forum about "Leementing", which is chock full of tips to fix the Lee mould venting problems. "Swirl" pouring helps most of the time, as does enlarging the sprue plate holes and wells with a 60 degree countersink.

Also, you don't specify whether that temperature you posted was alloy temperature or mould temperature. Alloy temperature has squat to do with good fillout or mould venting, MOULD temperature is the critical one. Run your alloy as cool as possible (100 degrees hotter than the end of the slush stage is ideal for most alloys) and cast fast to keep the mould temperature hot. Most Lee two-bangers that I have work really well at about 400 degrees with WW + 1 or 2% tin alloy at 675, or with 50/50 at 725 or so and the mould about 375. To keep the moulds hot requires three to four pours per minute sustained pace.

Hope this helps,

Gear

[btroj]

Bet it is a large caliber mould. 44 cal at least.

Mould is getting too hot. I have had that with my 2 cav RD moulds for 45-70. Keep the melt temp low and cast slower.

[sundog]

Lee-ment it, clean it again, then clean it again, warm it up and give it a very light smoke from a wood stick match or butane lighter. I like stick matches or hardwood sticks for smoke better than a lighter, but either will work.

And, what the others said.

[blaser.306]

I had the same trouble with a NEI mould,429-310 ssk. The way I fixed mine was Pressure pouring! When the metal inside the boolit was cooling and there was not enough sprue puddle still molten on top of the sprue plate for it to draw from, the fill hole would freeze and one side of the slug (hotter side) would colapse causing a ( waistline ) May be worth trying as it seems to have fixed my troubles! YMMV.

[geargnasher]

Blaser.306, you can fix that problem without pressure casting if you pour a bigger sprue puddle each time, this will get the sprue plate hotter and let the puddle stay liquid longer. This is an odd problem, since most of the time the boolits freeze before the sprue puddle does by a long shot.

Gear

[adrians]

just curious, do you use a bottom pour or are you ladle pouring?
i find ladle pouring to be more controllable in certain situations when bad fillout is present ,a tad of tin added wouldn't hurt either.
happy 2012 ,,,,,:evil::bigsmyl2::twisted:

[williamwaco]

Blaser.306, you can fix that problem without pressure casting if you pour a bigger sprue puddle each time, this will get the sprue plate hotter and let the puddle stay liquid longer. This is an odd problem, since most of the time the boolits freeze before the sprue puddle does by a long shot.

Gear


I get best results, best fillout, sharpest edges, least frosting, and zero wrinkles when ths sprue puddle is about the size of a nickle and twice as thick and takes three to five seconds to harden.

.

[btroj]

I don't think he is talking aout poor fallout in the traditional sense. I think he is getting someing I would call severe frosting. I get this when casting with multiple cavity moulds for really big bullets. The 425 RD can be made to do this quite easily.

The bullets are very heavily frosted on the side closest to the other cavity and end up with very poor fillout. I have always attributed this to excessive mould heat which is made worse by a large amoun of hot lead in the already filled cavity. Use the mould as a single cavity and this all goes away.

[Gohon]

Sounds like a venting issue, with a trapped air bubble collapsing when the boolit cools. I don't get what you mean by "inner cavity" unless you mean the one closest to the handles. If that's the one that's doing it, check your sprue plate for being too tight,

That was it..........already had gone ahead a boxed the mold up after my post so as to ship back for a replacement. Figured what the heck, cut the tape and took the mold out, set everything up and when the mold was well heated up I loosened the screw on the sprue plate. Tried just the offending cavity and out dropped a perfect cast. Tried both cavities and out popped two perfect casts. Got so carried away I cast another 300 bullets and not a single reject.

I really appreciate your help......never would have thought of something so simple. This old goat learned something today.......

[prs]

Happy endings always make me cry. ;-)


prs

[1Shirt]

It has been said that the U.S. spent large amounts of dollars to perfect a pen that would write in space. It is also said that the Russians used a pencil. Am a firm believer in the KISS principle.
1Shirt:coffeecom

[357shooter]

Gear and others, well done. Although I was looking forward to reading this thread for the next week of so. [smilie=l:[smilie=l:[smilie=l:

I didn't expect a slam-dunk-done.