Smeared Bases - mould temp question

[Dannix]

I got interrupted while casting the other day, and when I resumed, the mould required quite the hand strength to pry/slide the sprue plate, and the boolits were "smeared." I went ahead and called it a day as it was quitting time anyway.

The pot was at the same temp, PIDed, so the only conclusion I can come to is the sprue plat was too cold or maybe the whole mould was too cold, despite me putting it back onto the hotplate?

Thoughts?

http://castboolits.gunloads.com/imagehosting/thum_11153501a14badfb4c.jpg (http://castboolits.gunloads.com/vbimghost.php?do=displayimg&imgid=6106)

http://castboolits.gunloads.com/imagehosting/thum_11153501a14dcd332a.jpg (http://castboolits.gunloads.com/vbimghost.php?do=displayimg&imgid=6107)

http://castboolits.gunloads.com/imagehosting/thum_11153501a150262c88.jpg (http://castboolits.gunloads.com/vbimghost.php?do=displayimg&imgid=6108)

[chboats]

The mold was too cold. The sprue plate had to shear the harder lead. When hotter, the lead is a lot softer because it has not completely solidified or hardened.

Carl

[S.B.]

The mold was too cold. The sprue plate had to shear the harder lead. When hotter, the lead is a lot softer because it has not completely solidified or hardened.

Carl

I don't mean to disagree but, I've had molds do this when I am positve they're up to temp and they are throwing perfectly good bullets. I think the mold may be too hot and the alloy is too molten before the sprue plate is opened?
Steve

[mstarling]

Cadence is critical when casting. Wait just a bit longer before you cut the sprue!

Also ... look under the sprue plate. If alloy is smeared across the bottom of the place from the holes, you're running too hot or casting too quickly.

[Down South]

I believe the OP is referring to the base of the boolit being smeared after the interruption in his casting session.
What you are seeing is the results of the mould and sprue plate cooling down. Instead of making the small divot in the base of the boollit the sprue plate is actually shearing the sprue instead of partically tearing/ripping the very center of the sprue where it is the hottest.
Some casters including myself like to see the sheared base of their boollit instead of the divot in the center of the base.
I believe there is less problems with boolit weight variation plus you have a better base.

I do agree with chboats that the mould was colder but not necessarily to cold.

[Dannix]

Also ... look under the sprue plate. If alloy is smeared across the bottom of the place from the holes, you're running too hot or casting too quickly.
Actually, that was indeed the case. I guess putting the already at-temp mould onto the hotplate put it over the top once I was back to casting.

I should have checked the mould temp instead of just trying to cast faster to bring up the temp (which obviously didn't help). I'm used to working with too could of a mould rather than one to hot.


Instead of making the small divot in the base of the boollit the sprue plate is actually shearing the sprue instead of partically tearing/ripping the very center of the sprue where it is the hottest.
Some casters including myself like to see the sheared base of their boollit instead of the divot in the center of the base.

Interesting. It was my impression most here shot for the tearing/ripping route. Do you use cam levers on all your sprue plates? (My hand and forarms got quite the workout trying to pry/slide the sprue plate.)

[leadman]

From the looks of the boolits your mold is not a Lee 6 holer so a hardwood hammer handle and a whack on the sprue plate handle is all you need. Be sure to whack on the same angle that the sprue plate swings. If you find the right timing after pouring to cut the sprue it will not pull lead out of the center of the boolit.

Also make sure the edge of the sprue plate hole comes to a knife edge. Many of the Lyman sprue plate holes actually aren't tapered far enough down and the chunk of sprue lead sticks in the hole.

I have compared boolits with divots and without and as long as the boolits were sorted by weight I saw no difference in accuracy. I have several guns that will shoot MOA or less with boolits with divots so I don't know how much better I can expect them to be.

You can use the hammer handle to tap the mold handle pivot bolt to help release the boolits also. Never hit the mold.

[fcvan]

+1 on the divot thing not causing serious accuracy issues. I saw a post (with pictures) where the writer drilled the base of his boolit at varying depths and even off-center. He was trying to see if the change would throw the boolit off course measurably. Even the off center holed boolits flew accurately according to his post. I would think the out of balance boolits would eventually start to wobble at greater distances.

If I remember correctly, the writer noted than when the edge of the base was disturbed or altered there was noticeable effects on accuracy. I would guess that a nick or ding would expedite gas cutting or at the least cause disruption as the base of the boolit and the expanding gasses reached the crown of the muzzle. Frank

[Dannix]

It's the Miha 125grn 9mm HP mould.

[S.B.]

leadman, I've never had this problem eith any of the many Lyman molds I own but, have douns your statement to be true with Lee molds I own.
Steve

[Wally]

I found one can prevent a smeared sprued plate. Kepp a cotton rag by your side when you cast. When you see it smeared up wipe it off with eth rag. Then cool the opened sprue plate by placing onto a damp sponge. It will not warp it.


I use a lot of Lee molds and one must run them "hot", so this is a common problem. About every 4 ~ 5 casts I will press the opened sprue plate on the damp sponge and that prevents the problem.

[captaint]

I don't think any of us are using anything other than a gloved hand - once we get our molds up to full temp, are we ?? I have to use some sort of device to tap the sprue plate open on a cooler mold, when I'm starting out. But, once the mold is up to temp, I just open the sprue plate with a gloved hand. Maybe everybody doesn't do it that way ?? I will wait till the sprue puddle changes color, sucks down and blam, open er up. Seems to work OK for me... enjoy Mike

[S.B.]

captaint, can you spell "burned hand"? HEHEHE
Steve

[captaint]

S.B. - Seriously, gloved hand. Man, I'm no hero. I'll bet most folks do it my way. And if they don't - to each his own !!! enjoy Mike

[Doby45]

I use a gloved hand to open my sprue plate. Go to Home Depot and get the Lincoln Electric welding gloves for the cheap.

[chboats]

S.B. - Been opening sprue plate with a gloved hand for years. Haven't burned the hand yet but you learn not to hang on to it too long, it will get hot.

Dannix - You said in the OP that it was hard to open the sprue. If the mold was too hot it would have been easy to open with almost no effort.

Carl

[Dannix]

Dannix - You said in the OP that it was hard to open the sprue. If the mold was too hot it would have been easy to open with almost no effort.

Carl
Hum, maybe so. This is what I get for not dropping a thermometer on the mould before going back to casting with it. :veryconfu

It was both quite difficult to open, and smearing was also encountered. (A loose sprute plate was not the cause of the smearing.)


captaint,
I like to stay whack-free on my nice moulds i.e. exclusively gloved-hand action. I sit a little iron thermometer on the sprue plate and wait for a good temp before I start pouring. Actually, on this mould, the plate is so close to the mould handles, I would have a hard time whacking it.

[Lance Boyle]

I'm fairly new at this. I was smacking the sprue plate open with a pine 1x1 scrap until I figured that perhaps it was unnecessary and perhaps mold abuse.

I'm using a gloved hand now and yeah, don't dawdle doing it. ;)

Dannix, what kind of thermometer are you talking about that you use to take your mold temps. The only one I can picture working is the IR ones but am really curious about the one you mention.

I have a good thermometer for the pot but nothing for the molds.

[Dannix]

Dannix, what kind of thermometer are you talking about that you use to take your mold temps. The only one I can picture working is the IR ones but am really curious about the one you mention.
I'm sure there are much better options, but here's what I'm using. (I had this left over from my radio control days.)
http://www.coverite.com/accys/covr2410.html