Casting Technique for Good Base Fillout

[Ken in Iowa]

I'm starting to get the hang of this casting thing. :). One mould bugs me though. :?

I have been ladle casting with 1-2-97 alloy. I have 4 -Dual cavity RCBS pistol moulds that make beautiful boolits, so I must be doing something right.

The 45-230-CM is a little quirky. I use these boolits for Cowboy action. In order to get the square bases to fill out well, I need to run the melt between 700-720. I also need lots over over pour to keep the spruce plate hot in order to get perfect bases. The finished boolits are frosty and a little undersized at .4535 or so. I would like them to drop at least .454.

My similar RCBS 45-200-SWC likes to run much cooler, 650-670 is where it likes to run with the same alloy and similar technique and cadence.

Any thoughts on what I can do differently? I would like to run the 230 with a cooler melt.

[Larry Gibson]

Add another 1% tin for a 2-2-96 alloy or switch to a 2.5 - 2.5 -95 alloy. Cast at 710 - 720 degrees. Adjust spout open so hot alloy gets into mould as fast as possible. Pour a generous sprue even if it runs off the mould.

Larry Gibson

[John Boy]

Ken, nearly every mold is different - like women...
Bring the pot melt & mold up to the temperature so that with a 5 second pour (spout in the hole)the sprue puddle frosts in 5-7 seconds. The bullets will be completely filled out and base edges sharp.
I cast many different alloys and have never had to add Sn to make the bullets fill out. Only time I add Sn to the alloy is when I want an alloy that is known to produce good groups ... ie, COWW's and 1/2% of Sn

[pjames32]

720-725 is where I usually cast. Like Larry said a little more tin and keep over pouring the sprue plate. Practice makes perfect. Do you use a lead thermometer or PID?
PJ

[runfiverun]

just run a stone down the top corners of the mold, this lets the air out.
so does loosening the sprue plate a little.

[Cleve Branch]

I just finished a session today. I was having trouble with the same thing. Had to hold my mould a little farther away( was holding up tight to the spru plate) and let a little over flow.
Made a big difference

[Ken in Iowa]

Good advice everybody. Moulds are like women. Lol!

I use an RCBS thermometer and I'm ladling. With a dual cavity mould, pressure casting is tricky. :p

I have the over pouring down, so we're good there. :-)

Stoning the corners and adjusting the plate is simple enough, so I'll try that first.

Likewise, trying more tin is simple as well. I see Larry likes his Sn and Sb in balance. Nothing wrong in that if you have the tin to spare.;)

[ohland]

so does loosening the sprue plate a little.

I just finished a 280468s and 321232 casting session. I set my plates to swing loose when you tip them. I belt sanded both split washer ends smooth so the lock washer does not dig into the spre (RCBS uses a different washer, non-sequitor). I run my RCBS molds just as loose. Just make sure your temp is high enough (today I finally ran at 725) and they should fill out well. If you need a little help, a few ounces of tin are nice...

[MBTcustom]

First, do as R5R suggests and break the edge of the blocks to create a vent line across the top of the mold. I do not recommend loosening the sprue plate though. You want it just tight enough that you cannot move it by swinging the mold smartly. You want enough friction that you must shut it with your tapper, but no more than that.
After that, throw the lead straight down the hole, and linger over it after it puddles up. Half a second aught to do it.
Yeah, the lead runs off the end of the mold just a titch. No big deal. Often you are simply cutting off the stream before the cavity is filled because you see lead pop out the top and start puddling. This is not the case, you cannot see inside the mold, and it is not full yet.
Just don't quit filling it until it is full.

[wv109323]

I use a hot plate to pre-heat my molds. I turn the mold over on the hot plate and let the sprue plate get as hot as the mold. I agree with others you need to get the lead into the mold as quick as possible. If venting is a problem,break the edges to let the air out so the lead can get into the mold.

[ohland]

loosening the sprue plate though. You want it just tight enough that you cannot move it by swinging the mold smartly. You want enough friction that you must shut it with your tapper, but no more than that.

OK, in an infinite universe, infinite things may happen. My plates swing freely. They don't flap up and down, but they do swing.
Casting today, my bases were sharp. No torn out lead or lead sticking up. Cast, let it solidify and pull in, either switch to the next mould, or count to five (or ten...), whack the sprue lever, dump the boolit.

When I have tried casting with the plate too snug, I get fill-out trouble...

The other stuff sounds good. I'm just too lazy to touch up the underside of the plate... As long as my sprues cut smooth, I'm in no hurry...

[44man]

I have 100 or so molds and most I made my self. I do not over pour. I keep the spout of the ladle tight so there are no leaks and clean the nose if it tins.
I cast with the pot at 750° and regulate by time, frost will make a smaller boolit so I slow down. Pure I go to 800°. Not a single mold, mine (aluminum) Lee, RCBS or Lyman cast different or needs a notebook.
The secret to a filled base is to hold the ladle long enough to allow the boolit to take all the lead it needs from the molten lead in the ladle, never from the sprue.
Stoning the corners or one swipe from a very fine little file does help venting.
Makes no sense to keep over pouring and make a mess. The sprue will always be cooler then what is in the ladle. Feed your mold, FEED IT!

[ohland]

The secret to a filled base is to hold the ladle long enough to allow the boolit to take all the lead it needs from the molten lead in the ladle, never from the sprue.

Feed your mold, FEED IT!

Getting stoned may be useful here. With a double mold, it gets dicey with a swinging plate, and letting the ladle be in contact with the sprue hole. With my luck, I pull the ladle away and the puddle sneaks into the next cavity.

I have some 600 wet/dry that has been waiting to meet the underside of a plate. I have a 375296 inbound, and when I pull the sprue screw out (sand down the tips on the lock washer) that would be a good time to give the underside of the plate some flat lovin....

The last part sounds like Scott's turfbuilder...

[44man]

Most of mine are double. Just keep the mold flat and tip the ladle away, sprue size will not matter if you filled the mold.
Most guys I watch here turn the mold as they tip, seems one hand follows the other and it is funny. Can't walk and chew gum either I guess.
When you get the right fill, the dimple that forms in the sprue will be very, very small. Many of mine are flat.
Just takes getting used to. Let the first pour sprue just set before tipping the mold for the second pour. I run two molds at once, doubles and once in a great while I will get three going but pre heat is a pain.
Soon the flow will come to you! :bigsmyl2:

[williamwaco]

Did you notice?

The key here?

There are multiple ways to cast good bases but they all have one thing in common. The mold must be FULL.

Try these methods and choose the one that you like best.

One more opinion: Mold temperature is more important than alloy temperature. I can cast perfect bullets at any temperature from 600 to 750 as long as the mold is hot enough that the sprue is liquid after 3 seconds and hard at 5 seconds.

[bangerjim]

I haven't been stooooooned since college@@@@@!:veryconfu

I keep the sprue screw fairly tight. I had one 5 cav that the screw loosened up and the plate would swing when the mold was tilted..........instant burn on my left hand thumb where the plate hit it! never again......righty tighty for me. That is what the beveled washer is for. And that's what the mold tapper is for. And no, I have never worn gloves while casting......too much loss of movement and dexterity for delicate things.....so don't even go there. Only burn I have ever received from my toys.

If you still have problems, try pressure casting. Works for me every time with my bottom pours and a couple tricky molds.

banger

[ohland]

If you still have problems, try pressure casting. Works for me every time with my bottom pours and a couple tricky molds. banger

I figured out that I have to screw the bolt down farther on my Pro-Melt. As it was, the lead would splash back up from the cavity while pouring. Very annoying...

[Ken in Iowa]

Ok, the stoning did the trick! I noticed the difference on the first couple of pours.

I ran about 600 boolits with the modified mould. I was able to settle in with 650-670 degree melt. Boolit size increased to .454 or better, so that goal was met.

With the decrease in temp from the 700-720 that I needed before the stoning mod, I was able to speed up but frosting resulted.

Thanks for all of your responses.