First cast questions........

[saz]

I have finally done some casting 2 days ago. I cast with 2 lee molds- both 452- 300 gr rnfp and a 255gr rnfp, both molds were prepped with a good cleaning with mineral spirits and smoked, then prepped with bull plate (WOW does that stuff work good). I was casting at 700 degrees according to my lymman thermometer in my lee 4-20 pot using straight WW. Fill seemed to be pretty good, there were a few bases that were not quite filled out very well, but that was my fault getting used to the pot. One thing I noticed was that when I cut the sprues there is a small void in all the bases, almost like there were air bubbles in the base (the only way I can think to explain it). I'm not really sure why that was happening, and I am looking for some suggestions/advice or is that ok? Thanks in advance.

[chris in va]

Post some pictures if possible. I've had really good luck scrubbing the sprue/mold with dawn and water, takes the oil right off.

[JIMinPHX]

The air bubble like voids were probably caused by cutting the sprue too early. Try waiting another 10 seconds, then cut & see if that problem goes away.

I often cut my sprue early like that for general purpose pistol boolits, just because it's faster & if you're not looking for match quality, then they are usually still good enough.

As Chris suggested, pictures would help us to help you.

Congratulations on success with your first batch.

[fredj338]

The air bubble like voids were probably caused by cutting the sprue too early. Try waiting another 10 seconds, then cut & see if that problem goes away.

I often cut my sprue early like that for general purpose pistol boolits, just because it's faster & if you're not looking for match quality, then they are usually still good enough.

As Chris suggested, pictures would help us to help you.

Congratulations on success with your first batch.

That & maybe not a large enough sprue? I find the base voids happen more easily w/ the thin Lee 2cav sprue plate.

[Wayne Smith]

If the void is smooth it is likely not enough lead on the sprue plate to pull down as the boolit cools. If it looks torn Jim's got it - cutting the sprue too soon.

[Buckshot]

" Fill seemed to be pretty good, there were a few bases that were not quite filled out very well, but that was my fault getting used to the pot. One thing I noticed was that when I cut the sprues there is a small void in all the bases, almost like there were air bubbles in the base (the only way I can think to explain it)."

.........You said, there is a small void in all the bases, so "A small void" is singular and if under the sprue hole may be a few things. A high antimoney content make the alloy brittle and the sprue can tear. Or it may be the sprue hole isn't edge isn't sharp, or finally the sprue hasn't completely setup yeat and you're tearing alloy out. Regardless, the tear will be ragged in appearance.

But then, "almost like there were air bubbles in the base which is plural and if this is the case, that they're distributed across the base then possibly you used a bit too much Bull Plate lube. If they look like tiny 'half bubbles' and their indented surface appears smooth, I'd bet that's the problem. That or the underside of the SP is still contaminated by preservative oil.

The mould should be hot when applying Bullplate, and the applied lube's appearance should be the bearest sheen on the surface. I barely dip the tip of a cotton swab in the lube, then let it migrate through the tip. It should be the faintest bit 'off white' when compared to the other end.

.............Buckshot

[runfiverun]

it's tearing from opening too soon.
the unfilled bases are from not getting the sprue plate hot enough.
try pouring the opposite hole every other pour.

[saz]

This is why I love this forum. You were all right- I went to cast a few more today, and I figured I would break in my new lee c310-430, so I cleaned and prepped it as per lee's instructions (mineral spirits then smoke the mold) and I waited about 15-20 seconds longer between cutting sprues and voila!!!!! CLEAN CUT BASES!!! Yeah, I know it was something very simple but it feels like a gigantic victory. This stuff is so much fun!!! As I was reading I remembered a few threads about "leementing" so I went looking for them. I went ahead and boiled my molds in water, cleaned again and I just cast a few more boolits for polishing the molds as they are very sticky. I am a little dissapointed as all three molds drop .001-.002" under what I need for size, so I guess the "beagling is in order, but I couldnt find any 3M foil tape that is supposed to be used. All I could find was some other brand I had never heard of that was almost .015" thick- a little too much. Oh well, I will keep looking. Thanks again everyone for all of the GREAT advice!!!

[RICKLANDES]

Changing your mix will bring up the size the mil or two you are down

[462]

saz,
Smoking a mould will make it drop smaller boolits.

[Recluse]

I am a little dissapointed as all three molds drop .001-.002" under what I need for size,

Saz,

1. Re Lee-ment your moulds, and make sure to thoroughly lap the cavities. I typically use TWO boolits, one after another, when lapping each cavity.

2. Make sure your vent lines are opened up (per the Lee-menting suggestions).

3. Forget smoking the molds. That will reduce size, the smoking is only temporary, and if you Lee-ment thoroughly and correctly, the smoking of the mold is completely unnecessary.

4. Add some tin to your alloy--solder will work. You'll get better fillout.

5. Cast with a bit more heat. I'd suggest 800F. It's hard to frost a boolit with an aluminum mold. Not impossible, but just takes a bit more doing than with a steel mold.

[Buckshot]

[QUOTE=saz;867597]This is why I love this forum. You were all right-QUOTE]

............Yeah and besides that, we're a darn good lookin' bunch too

............Buckshot

[saz]

[QUOTE=Buckshot;868445]

This is why I love this forum. You were all right-QUOTE]

............Yeah and besides that, we're a darn good lookin' bunch too

............Buckshot

HA HA!!! I tell myself that every morning in the mirror, and my wife just scoffs.... Oh well.

Here goes: I "leemented" again with comet, two boolits to every cavity, raised the melt temp to 800 degrees and added all the soldier that I had (it was only like .5 oz)to the 20lb full pot and I have to say, my boolits look MUCH better! They dont drop them right off the bat but they are getting a whole lot better. The 255gr RNFP will drop them as soon as the mold cracks open and throws some pretty looking boolits. They seem to have a little rounded edges, probably due to not enough tin??? The c300-452 is working a whole lot better now- one tap on the hinge pin and they fall out and look very good. That mold was used, I picked it up with a lot of brass and some other things and a friend of mine said " that thing is junk"- whatever. The new c310-430 is coming around. It does drop some pretty boolits, but they seem to stick in the left side block every time. I dont see any burrs or anything, so I'm not really sure why it is happening. I an going to wait until morning to measure them and see if they are any bigger. The .44 mold was dropping boolits right at .429- I need .432. We will see what happens.

[Buckshot]

................If all it takes is a tap or 2 on the handle hinge to get the boolits to drop then that's no real big deal. Not perfection, but perfection is rarely encountered and it's only when you have to beat the living whey out of a set of blocks to get the slugs out, that you wonder is it worth it?

A small amount of magnification can show up things even a close examination with the naked eye would never be seen. If you can, pick up a jeweler's loupe or a hand held magnifying glass. Have good light on the subject and slowly give the problem cavities a close once over. If you do find something like a bit of a positive ridge that's causing a slug to hang up you may be able to use a hardwood toothpick to burnish it down. If that fails before I'd use an Ex-Acto knife or similar try a piece of copper tube. Just crimp the end down with pliers and use the end of it to knock it down a bit.

.............Buckshot