Auto master caster leading up with fan.

[Tazza]

So, riddle me this.....

I have a MC that is automated, i have a fan to cool the mold down to give nice clean looking projectiles. The issue i get is after a few hundred drop out, lead builds up between the pivot point on the sprue cutter and mold. This pushes the cutter out a little and you get a bump on the back of the projectile. It's not nice and smooth after the BB, but a bevel then a raised bit. It adds variation to the weight and doesn't look as nice as where the lead picks up, it runs like a gouge on the back side too.

Now, the strange part.... If i don't turn the fan on and run it hot, this doesn't happen. Hot enough that the projectiles that fall are frosty, but have a nice even base. You can see lead build up on the mold surface, but it's very thin and doesn't cause any issues. I cast about 6,000 last saturday like this without any issues or needing to stop to scrape the lead off with a snap knife blade.

I can't use lube as i coat the case projectiles in polymer, so any oils are bad for making it stick.

I always thought keep it slow and cool and lead will not build up, but for me, all my molds build it up if i don't run them hot.

Has anyone else had issues like this? or is it just an aussie thing with our lead spinning the opposite direction? :P

[VHoward]

Have you tried setting it so the mold spends less time under the fan?

[Tazza]

I have, that's why i'm confused.

[Tazza]

The only thing i can think of is that one projectile isn't always dropping. When it doesn't, the little bump from where the sprue i cut off can push the cutter out a little and when the other cavity fills, it over fills that little bit more allowing lead to get between. It possibly keeps going each time one is stuck?

I'm just guessing is all. Just strange, i know commercial units don't have this issue, but have far lower cycle times. If i go too low, i have fill out issues due to the mold being too cold. Catch 22 situation.

[OS OK]

Would a little tightening of the sprue plate help…taking up that space that seems to spring up with cooler lead under the sprue plate? Or honing the bottom of the plate to sharpen the cutting holes?

OS OK

[Tazza]

That's the thing, how tight is too tight? i thought i had it tight enough, but you never do know.

Sharpening the holes isn't a bad idea, I'll have to give that a go.

[ReloaderFred]

It's a lube problem. If you'll apply a very small amount of lube to the area around the pivot point of the sprue cutter, that should take care of the issue. I use a Q-tip to apply lube to just the top of the mold, keeping it out of the cavities. The lube will prevent the lead from sticking to the top of the mold.

I was buying the expensive mold lube from Magma, but a member here suggested using PAM, the cooking spray to keep food from sticking. I tried it straight from the can, but couldn't regulate how much got on the molds and it went everywhere, including getting inside the mold cavities and causing many wrinkled bullets.

I now spray some of the cheapest PAM substitute ($2.99 US per can) into the spray bottle that came with the Magma lube. Then I mix it with denatured alcohol, shake it up, and spray the Q-Tip, then apply as needed.

I also have a Bullet Master machine that runs 8 molds. If I don't keep the sprue cutters and mold tops lubed, it causes all kinds of problems. I spray those molds, but with bullets still in the cavities, to keep as much lube as possible out of them.

Hope this helps.

Fred

[Tazza]

I'll have to give that a go. I currently use a drop or two of synthetic oil on the pivot point, but it gets everywhere pretty fast, i like the alcohol and Q tip idea to better control it.

I used to do this when it started to squeak, the problem is, when you hear it, it's already too late, there is lead stuck.

[runfiverun]

try turning the melt pot temp down a bit.
and leave the fan off.
you'll find the balance, it's just like casting where you open the mold by hand.
there is a fine point where you either open the mold real soon and kind of smear the bump away then let the boolit cool.
or open it just at the right time avoiding the hard bump but taking the chance of having a little tear in the base.
or wait till the boolit has completely cooled down then actually cut the sprue off.
if the cutter is dull or angled you'll get a lump.
hitting the plate at an angle can create the bump too, but closing it and opening it again will generally cut it off flat.

you just want the sprue plate flat.
if you over tighten it, it will raise the plate up on the other end.
under tighten it and the plate raises closer to the screw.
if the plate is not flat you'll end up with a bump on one end or the other or worse lead flows under the plate creating a small fin around the base of the boolit.

anyway you got something just a little bit out of spec/alignment/timing your just gonna have to track down which one it is.

[Tazza]

I run my pot pretty cool, 340c, i used to be even lower but i had spout freeze some times when adding metal to the pot. I can try bring it down a little more, see how it goes.

When had casting, you have so much more control, you can see and feel what it's doing and adjust your timing to suit. When up to temperature, pretty well every projectile you drop is perfect.

Thanks for your advise guys, i'll have to fiddle some more, see if i can get it casting just right!

[runfiverun]

it took me a bit to get the hang of the M/C when I first got it.
I was just running the thing too slow.
everything come out looking nice and pretty but I was running on the verge of too cold.
then I swung the other way and got the smears.
I had to keep on putting something on the mold to stop the smears.

[Mica_Hiebert]

My guess is the fan is solidifying the sprue sooner and the sprue plate is trying to cut it too late. Maybe speed up when using the fan.

[Tazza]

Hopefully i'll get time on Saturday to have a play, see if i can work it out. Even if i can get it running faster i don't mind, get more done than i would usually do.

[Tazza]

The oil i use was given to me my a guy that used to drive fuel trucks. It apparently was an additive that they used, it handles high temperatures and is slick as. He used it on his guns for that reason.

Other than that, i really don't know what it was.

[wymanwinn]

Hopefully i'll get time on Saturday to have a play, see if i can work it out. Even if i can get it running faster i don't mind, get more done than i would usually do.

Tazza,

i run my Hatch/Wyman MC at 725F and the cycle is about 10 seconds...pour, 2sec hold, drop and hold for about 4 and return....the fan is wide open...never had your problem...my sprue plates are pretty snug and i, like ReloaderFred, lube ONLY the top of the mold and the backside of the sprue plate with Bullplate using a Q-tip...i also lube the rails and sprue trips with the Bullplate....i do this about every 1500 rounds or two hours....and when changing molds....

wyman

[Tazza]

Thanks for the ideas guys, i'm planning on a day of casting tomorrow, see if i can make it a trouble free day :)

[runfiverun]

airc wyman has a couple of nice video's of a couple of his set-up's posted here somewhere.

good to see you around posting again Wyman.

[wymanwinn]

airc wyman has a couple of nice video's of a couple of his set-up's posted here somewhere.

good to see you around posting again Wyman.

thanks, i know i have been kinda absent....but i still lurk around...LOL

:drinks: