Finally did some casting today & a Question

[JWFilips]

Hi Guys,
Finally got back into the saddle today! Haven't been able to do much since mid August because of a Sciatica problem that has really set me back but as of a few weeks ago I started to improve each day...so I decided it was time to try casting. Not too bad, but paying a bit now, but the accomplishment was worth it.
Wanted to cast up some Plain Base Noe 165 gr Ranch Dogs for my 30-30 marlin & cast up a bunch of Noe 340-224Gr plain base to be used in my well worn ( now .33 cal ) JP Sauer und Shon 98 Mauser. I size them down to .330 and the shoot great ( thanks to Ben for this idea)!

I also had a run of strange bases...I have seen this before but can't put my finger on it. Not sure if it is because too tight of a sprue plate or too cool of a sprue plate Alloy was run at 720 deg Everything flowing well and a good pool on the plate...only happened on the big 224 grain bullets once in awhile...nothing unusually about the casting session.
Any of you guys know the cause of this ( see 2nd photo)
Thanks
Jim

 

[Brad]

Based on a post in another thread I would consider enlarging the sprue hole just a bit. Ric mentioned 65% of bullet diameter and I see no reason why that doesn't make sense.
Looks to me like the lead on one side solidified before the cavity was entirely filled. Getting the lead in faster would help.
Bottom pour?

 

[yodogsandman]

Sprue plate too tight or poor venting? Some bases look a little rounded.

Glad you were able to try casting again, hope you recover fully soon.

 

[David Reiss]

This kind of thing can happen when the mold gets cold and not having the sprue not lined up with the pour spout. The lead is hitting the side of the sprue plate hole. This typically only happens with bullets only .30 or smaller. The sprue being too tight or poor venting doesn't lead to this type of issue. If it was poor venting, then you would have issues on other parts of the bullets as well.

Sorry for the typo, corrected it.

 

[Brad]

David hit it. Get the lead in without it solidifying on the side of the cavity.

 

[David Reiss]

Try also moving the sprue hole over a little closer to the edge of the base and continue to pour. You should get good bases right away while the mold comes back to temperature.

 

[JWFilips]

Brad,
Yes bottom pour.... 1/2 inch from the spout ...full flow ( about one in every 10 pours showed this) Bugged the heck out of me.
Accidentally got the pot up to 750 deg for a bit and it stopped ...That is why I thought is was too cold a sprue plate (Had a fan running)

 

[Ian]

Too cold, Jim! Cast faster, and fill the cavity faster so the splashes don't freeze on the side. Your bases will fill much better if the whole mould is a lot hotter, so pour more lead on top to link the sprues and get as much as you can on the sprue plate without it spilling off and making a mess.

 

[Rick]

Too cold, Jim! Cast faster, and fill the cavity faster so the splashes don't freeze on the side. Your bases will fill much better if the whole mould is a lot hotter, so pour more lead on top to link the sprues and get as much as you can on the sprue plate without it spilling off and making a mess.

^^^^^^^^^^^^^^^^

Yep, but a hotter mold/sprue plate not hotter alloy.
.

 

[Brad]

LADLE, a Rowell is even better. Way easier to control mould temp.
Rick finally convinced me to try and I haven't bottom poured since.

 

[JWFilips]

Ian,
Pretty sure the mould was hot because I had major frosting on the bands! that is why it is a puzzlement to me! Also center of the pour was centered on the sprue hole.
Located mould 1/2" from spout to 1 " from spout no difference Higher alloy temp was the only thing that made a difference. My Normal alloy always pours successful at 725 Deg
The 165 's no problem the 224's is where it started but it wasn't consistent...I just find it strange
Jim

 

[JWFilips]

LADLE, a Rowell is even better. Way easier to control mould temp.
Rick finally convinced me to try and I haven't bottom poured since.

I may just give this a try in the future! Seems the guys I look to most do it that way!

 

[Chris]

I'm a bit late on the reply, but I echo what others said above. Rowell ladle, keep pouring some heat on the sprue plate and let the lead run back into the pot.

 

[Rick]

Ian,
Pretty sure the mould was hot because I had major frosting on the bands! that is why it is a puzzlement to me! Jim

Then it is the sprue plate that is too cool. Can't pour good bases with a cool sprue plate any more than you can pour good HP noses with a cool spud.
.

 

[David Reiss]

1/2" to 1" is way too far away. I stand on my comments.

 

[Ian]

Then it is the sprue plate that is too cool. Can't pour good bases with a cool sprue plate any more than you can pour good HP noses with a cool spud.
.

Yep, this. Also, when using a Lee bottom pour at full-tilt wide open, the lead sprays through the orifice in a high-velocity stream. This stream splatters around inside the mould, churning and throwing lead everywhere. A big slash is going up the side and freezing on the bottom of your too-cold sprue plate. Also, the rounded bases are a big indicator of lack of heat in that area, together with the "wrinkles" . Too much Bullplate can cause the same thing but usually burns off sufficiently on its own in ten or so pours to cease being a problem.

Most of my bottom-pouring is about 1/4" below the spout, at the slowest fill rate I can get by with. I also peened my spout to reduce the jet-stream blast of metal somewhat. Ladle pouring at high volume, low pressure is the best way ever to fill a mould, even though I rarely do it that way due to my insistence of casting indoors, in a climate-controlled room, in a comfy chair, with my tunes and vent-hood going and a very predictable and consistent draft. When I ladle pour it's with 80 pounds of alloy in a huge pot between my knees, big propane fire under it, and a 2-lb Rowel ladle in git 'er dun fashion.

 

[fiver]

David has a good point.
lining up the alloy stream and hitting it hard on the long skinny bullets seems to fill them out the best.
but I'm thinking you have a bit of cold going on here.
the alloy rolled up the side of the mold and hit the plate then froze in place.
this can happen even if the mold itself is plenty hot.
the fan was sucking the heat away from the sprue plate.

 

[Brad]

I am proud of Jim for noticing a repeatable flaw and wondering what caused it. Too many people wouldn't notice the common flaw and even question it.

Nice observation Jim.

 

[KHornet]

Hot and fast may cure it!

 

[David Reiss]

Brad is right on it. I might add that you are not much of a caster if you haven't experienced a flaw, that when it happens, you wonder what the hell is going on. Sometimes you know it happen once before, but that might have been 15 years ago and you can't just pinpoint the cause. It is even more frustrating when you are casting with two similar molds and it's happening to only one of them. One thing I learned from a caster with 70 years of experience has helped over the years. And that is keep notes on your molds. From his advice I keep a log of all my molds and anything particular about that mold, such as which bullet may cast larger in a two cavity or this mold takes 10-15 casts until good and so forth.