This is what happens

[HangFireW8]

When you play with alloys while casting. I was trying to find out what worked with my new RCBS 30-180-FN mold, tossing in a few extra nuggets of monotype, and then cutting it back with pure(ish) lead and WW, and trying temperatures from 550F to 710F. I suspected some of the mixes were pretty high in tin, and I want to reuse the mix at some point, thus the weighing, to see just how far things had gotten.

http://castboolits.gunloads.com/attachment.php?attachmentid=164422&d=1458876531

The main problem was, poor fill-out on one side of the boolit, both cavities, same problem. Thus, playing with more tin. The cavities were ultra-clean, but I cleaned and checked them again.

Next I drained the pot and mixed up a batch of WW+2% Pewter (by weight) and that's the 193.5gr column on the right. These were all the "good" boolits from about, oh, 600. The other 500-some all had a shrunken side. I'm nothing if not persistent. It seemed like it filled out better at higher temps, but I couldn't do much there, the boolits stuck something awful at higher temps, too. That makes maintaining mold temp really hard, when it takes 2-3 minutes to bang out both cavities. Pressure casting (I have a Lee 10lb drip-o-matic) worked, and stuck boolits something awful, too.

After 3 sessions of this I was about to send it back to RCBS when I read the instructions, it said they use Linotype and had directions for ladle casting. I do ladle casting, on special occasions, but then again, sticking bullets, and I'm not going to mix up a batch of linotype for just one mold. I'm a WW+2% kind of guy.

So I go over all my other steel mold notes, and notice another mold with the same issues, fill-out and sticking at high temps (by high I mean 700F). I take both (the other is a 323470), Clover 240, medical swabs and my drill/driver, and got to polishing cavities.

Viola'! Both molds start dropping easily at 700F. For the first time in, ever, since I bought it in 2009, the 323470 was a pleasure to use, and I got a lot of useful boolits out of one session. The 30-180-FN produced a bunch of good stuff as well. All the 30's from this last batch (that I've weighed) all weigh real close to 193.5. That's the WW+2% Pewter, one of my standard mixes. Curiously the polishing changed the weight not a bit.

The moral of this story- buy custom maker molds, of course, but the other is, even if a steel mold is burr-free, well ventilated and absolutely clean, if it sticks boolits at higher temps, polish it.

[leadman]

It does help to use a wooden match to smoke the cavities. I also set my molds on a piece of steel plate to act as a heat sink on the bottom of the mold. This aids in pulling alloy from the sprue puddle and better filled out boolits. The lapping usually does a good job as you found out.

[William Yanda]

" I also set my molds on a piece of steel plate to act as a heat sink on the bottom of the mold."

Now that idea sounds as handy as pockets as someone else said here.
Bill

[Walter Laich]

I used to polish all my Lees 'just because'

It sure does make a difference and really doesn't take that long in the grand scheme of things.

[runfiverun]

you got the burr off the edge of the cavity's.
that little burr was locking the boolits in place.
you gotta look for stuff like that I run a Q-tip back and forth across the edges you'll either feel or see the strands grab and tear out.
those areas need attention.
usually an X-acto blade will clean everything up nicely if you have good magnification.

[HangFireW8]

you got the burr off the edge of the cavity's.
that little burr was locking the boolits in place.
you gotta look for stuff like that I run a Q-tip back and forth across the edges you'll either feel or see the strands grab and tear out.
those areas need attention.
usually an X-acto blade will clean everything up nicely if you have good magnification.

I expected at least one condescending response like this, and I'm not surprised who it came from, either. It's hard to post anything on here anymore without getting a response like this, as if I'm a newbie. Part of the same crew that ignored my accuracy advice and then discovered it on their own, the hard way.

It's not all about burrs. Both molds were thoroughly inspected. Every edge and every groove and every vent line. The RCBS was near perfect and dropped boolits just fine up to 640F. That doesn't happen with a Burr.

Sometimes it's 181 degree cavities, sometimes the machine finish. For the 323470 it's the many deep square Loverin-like grooves. Getting them a little less parallel and more pyramidal in cross-section is what made the difference. That's why I didn't use a cast boolit for lapping. With the RCBS it was the machine finish. I even stayed away from the edges because I didn't want a more prominent part line.

Is this good enough magnification? :)

http://castboolits.gunloads.com/attachment.php?attachmentid=164491&d=1458935149

[Texantothecore]

What is clover 240?

[HangFireW8]

Lapping compound.

[Texantothecore]

Thanks, I will check into it.

[ShooterAZ]

Every mold of mine has a temperature sweet spot, for each different alloy I use. I keep notes to help me remember, cause I never remember. When I hit that sweet spot, the boolits just fall out of the mold when I open it. With a brand new mold, sometimes it takes 3-4 sessions before it will drop boolits that easily though. I have never had to polish a mold, with the exception of some used (abused) molds that were given to me. They were rusty, but cleaned right up with a toothbrush and some comet. PS: I do not believe R5R's comments are condescending. He is just trying to help you. I don't understand your advice to buy custom maker molds. RCBS makes some damn fine molds, I never had a problem with any of mine, ever, and I have a whole bunch of them.

[HangFireW8]

ShooterAZ- That's just the issue. The sweet spot for this RCBS mold for fillout was not the sweet spot for fall-out, even after trying different alloys at different temperatures. I thought that unusual enough to make a post. Unlike some, I first try to work out issues and explore questions myself before rushing to post to the forums. Like you, I never had to struggle with a new RCBS mold before.

Perhaps the sweet spots would have coincided if I was using a ladle and linotype as the instructions suggest, with that amount of tin, easy fallout from shrinkage, lower melt and higher mold temps are a given, but that's not how I cast. Thus, intervention was required. It is a first for me with RCBS, except for an ancient beat-up Ohaus mold I picked up on eBay, none have needed polishing much less deburring before. I check them all on receipt, nonetheless.

I keep notes, too. I use my phone to take pics, it syncs them using secure webDAV with my ownCloud server. Then whatever laptop or desktop I am near, the pics are already there. I can pull up LibreOffice, import the pics, type in notes at 72WPM, and when I save the document, OC syncs it with all my other laptops and desktops. I keep a document per smelt batch, a document per mold, and some spreadsheets with ingot, mold, top punch inventory, etc., etc. Each mold document has weather, humidity, alloy, temp and other observations for each session.

Best of all, I get all the benefits of cloud sync and document sharing with zero bytes over the Internet for anyone to snoop on. It all stays on my LAN. If someone wants to see my bytes, they have to get a search warrant and break down the door. If some cloud service on the Net goes belly up, sold, becomes non-free, etc., mine just keeps on running.
http://castboolits.gunloads.com/attachment.php?attachmentid=164505&d=1458948674

Since I already solved all the problems, I'm not sure who RVR was trying to help. There is a history here of jumping in with the obvious while ignoring just what was said and what is known.

[ShooterAZ]

Well you're a hell of a lot more anal than I about record keeping. I keep a simple 3 ring binder with all my notes, I'd like to see someone snoop that off the internet. As you know, new molds can be a little tricky to figure out sometimes. I don't worry about poor fill-out when I first get them. This is because I know they may take several casting sessions before they settle in, and I find the sweet spot. Patience is the key. Sorry, I'm not aware of your history with R5R, he has been nothing but helpful to me. Glad you got it worked out.