Beagle-ing a mold

[1bluehorse]

Having read several posts mentioning doing this to enlarge a molds cavities, and having seen pictures of this being done...(but not having tried it myself) my question is how do you keep the mold from "flashing".....I must be missing something in the process...

[JWFilips]

I have beagled a bunch of my moulds and never had flashing ( except if I try to pressure pour with the spout on the sprue plate. I don't know why it won't flash but it may be because you are only opening it up a thousanth or so

[Pb2au]

I am going to toss this one out there.
Surface tension of the molten alloy is strong enough to prevent it from passing into the relatively narrow gap created by the shim material. It is like a tiny bead of water on a plate of glass. When examined closely, it does not lay flay, but essentially forms a hemisphere, help up by the surface tension of the water.
At least this is my hypothesis. I might be full of fertilizer on this one.

[shredder]

I do it too and get away without the flash. Best thing to do is try it for yourself.

[myg30]

Its an inherent miracle that was handed down to the creators of this forum and it ONLY works for cast boolit members. We don't ask and they don't tell ! They might be kin to Elmer K. ?

A little lead stuck between the cavities is {guess} .008"+/- and causes flashing. A thou or two wont. Pb2Au explanation sounded good.
Try it you'll like it !

Mike

[JonB_in_Glencoe]

I surely don't have the scientific answer as to "WHY",
but, from my experience using alum foil HVAC tape,
that opens the mold about .003" doesn't create flashing,
but I've had molds that have had a small piece of debris hold a mold open, so the boolits dropped are about .005" larger or so, then I'd get some flashing. It seems to be a fine dance.

btw, Beagling only widens the boolit in one direction, it will probably measure the same at the 'seam' as before it was beagled.

[oscarflytyer]

Something a Lee engineer recommended to me. Slip a small piece of cigarette rolling paper between the mold blocks, farthest away from the handles. Stick the paper piece on with a spot of beeswax. Slightly larger (.001-.002"). Haven't tried it yet.

[JonB_in_Glencoe]

Something a Lee engineer recommended to me. Slip a small piece of cigarette rolling paper between the mold blocks, farthest away from the handles. Stick the paper piece on with a spot of beeswax. Slightly larger (.001-.002"). Haven't tried it yet.

Them dang people at Lee
They are always tellin' folks to smear beeswax on their molds[smilie=b:

[Alan in Vermont]

btw, Beagling only widens the boolit in one direction, it will probably measure the same at the 'seam' as before it was beagled.

Does sizing swage the boolit back to round? If not, what is the benefit? Seems like people get all manner of whiney if the buy a mold that casts out-of-round.

I've got a 429348 that throws too small for the throats as well as the bore on my Charter 44 Spl. Probably a perfect candidate for beagling but the oval shape just seems wrong to me.

[JonB_in_Glencoe]

Does sizing swage the boolit back to round? If not, what is the benefit? Seems like people get all manner of whiney if the buy a mold that casts out-of-round.

I've got a 429348 that throws too small for the throats as well as the bore on my Charter 44 Spl. Probably a perfect candidate for beagling but the oval shape just seems wrong to me.

Well, here's my story.
I have a custom Jap 38 rechambered in 257R x 6.5
The bore slugs to .2685" groove dia.
I have a Lyman 266469 mold that casts a weak .268
I beagled it, the boolits then measured .271 x .268
I seated a copper Gator GC and sized them to .269
the sizing didn't swage them to a round .269 as I hoped they would.
while the GC was a round .269, the boolit body was .269 x .268
the GC seemed to seal the bore enough to prevent gas cutting and lead fouling the barrel, and the wide part of the boolit seemed to grab the rifling enough.
I didn't load them too hot, but, in the end, I didn't get the accuracy I wanted so I upgraded to a NOE 269-145 FN

I bet the beagling would be much better for a large caliber pistol, then a rifle boolit that'd need better concentricity (is that a word?) than beagling can deliver.