newish Lee 356 125 2R has become troublesome

[JonB]

A couple months ago, after the big suppliers started getting Lee molds in stock, I bought this new 6 cav 356 125 2r. I had been casting lots of NOE 128gr SWC for 9mm (my friends have hungry guns). One of them asked for some RN bullets. I've never had a RN mold for 9, so I figured, what the heck...and honestly, since this current shortage I had rarely cast for the 9.

I've been casting lots from this mold and from the get-go, it was dropping nice looking 129gr 0.3575" bullets easily. A typical session yields about 400 to 500 bullets. I think in the couple months I've owned this mold, I've cast a total of about 4000. Yesterday, the last session, The mold sat a little longer on the hotplate than the usual 20 minute startup...I got side tracked, it was on there for 90 minutes. I don't think is was overheated per say, because when I started casting, the pours froze in the usual 4 or 5 seconds, but the bullets seemed to cling to the cavities a bit more than usual. As I continued casting, the cavities seemed to get more clingy...until I was about halfway through the pot (250 bullets), and it got so clingy, to where I had to "pick" them out of the cavities with a small screwdriver. So I stopped and let everything cool down.

I inspected the mold. I did not see anything unusual with naked eye. I fire up the pot again, and preheated the mold. I had sticky cavities on the first pour, I continued to make about 20 pours...mostly to have some for Leementing (spinning a bullet in the cavities), thinking Leementing was a high probability to make this thing cast well again. I had run all the other casts through the Star while things were cooling off, so I didn't have any unsized left.

So here I am, taking some photos, as sometimes problems are easier seen via digital photos. I don't see anything on the photos, so I figure I'd post them and see if anyone here can see something I missed? Also, let me know your thoughts...maybe I am overlooking something? I plan on Leementing this mold sooner, than later, as I'd like to get some more cast...otherwise, I'd just let it sit until wintertime.

The Bullets always stick on the Right side.


Left side


Right side


Right side in less light


Right side zoomed in 3 cavities closest to hinge.

Right side zoomed in farthest 3 cavities

 

[Ian]

Smoke 'em a little and try again. Or go straight for the chrome polish.

 

[462]

Shirley strikes again. I see piled up burrs along the hinge side of the cavities.

I had a 458-500 that was much worse.

 

[GRMPS]

That's my go-to 9mm mold.
When newer molds stick I run the base of a carpenter's pencil or piece of wood around each cavity to remove possible burs.
Is that white film on the last picture left over from cleaning the mold?
I would re-clean the mold with solvent (acetone/brake cleaner) then dawn dish soap scrubbing well with either a toothbrush or denture brush then lightly smoke the mold and that usually fixed the problem.

I don't think you can warm the mold for too long you take a mold up to 400 for 30 minutes to season them. I've left mine on my hotplate @ 400° for several hours when I was casting with another mold.

I'd save polishing for last since that mold already drops big

 

[JonB]

This mold was cleaned once (dish soap and hotwater and toothbrush), right after I got it. Since it cast well during the first session, I never cleaned it again. There have been 8 to 10 sessions...no additional cleaning. no problems until yesterday.

I don't "feel" any burrs.
I don't think what we are seeing as burrs, are burrs?
Same with what looks like water stain on mold face.
I am wondering if both of those things (stains and what looks like burrs) are actually a oxide residue from the alloy, that is carried by the 2 cycle oil vapor that I use as sprue lube ???

Obviously, I've cast with other Lee 6 cav molds, many times before, using the same technique that I'm using with this one. But this is the first one with such extensive venting...plus I have cast alot with this mold, I usually don't cast such large quantities.

 

[JonB]

I do run "this" mold a bit hotter than other Lee 6 cav molds I have, that's what it wants.
ALSO,
When I wipe the Q-tip (with 2 cycle oil) on the bottom of the sprue plate, I do notice alloy residue (from cut sprues?) that gets wiped off (or wiped around) with Q-tip. I do try to let any vapor flash off after application...but who knows?

I also notice lots (more than usual) of alloy partials (like sand), in the towel in the area where I cut the sprues

 

[Ian]

Waiting about .5 to 1 second more before cutting the sprue....or giving the sprue plate a whiff of air from a small fan...might help the sandy lead issue.

 

[Jeff H]

I do run "this" mold a bit hotter than other Lee 6 cav molds I have, that's what it wants.
ALSO,
When I wipe the Q-tip (with 2 cycle oil) on the bottom of the sprue plate, I do notice alloy residue (from cut sprues?) that gets wiped off (or wiped around) with Q-tip. I do try to let any vapor flash off after application...but who knows?

I also notice lots (more than usual) of alloy partials (like sand), in the towel in the area where I cut the sprues

I'm thinking "burrs" too, even though you can't see them. I went thorugh this on my own most recent mould. My last Arsenal mould got the normal toothbrush (M16 cleaning brush)/Dawn/HOT water/Barkeep's Friend/hot rinse/BOILING rinse treatment. That USUALLY is enough to knock off burrs I can't see, but not this time. I had to give it a second "go" with extra emphasis along the edges of the cavities. After that it was OK. It initially took some casting to move/raise the little burrs such that they became a nuisance, so the problem - SYMPTOMS were the same as what you're experiencing. This is not normal for Arsenal, by the way. This one had a couple minor irritations, but I think he was struggling to keep up with demand. They are WAY nicer out of the box than any LEE I've bought, even though the last few LEEs I bought were actually almost impressive.

If the 2-cycle oil is haunting your conscience, eliminate it from the equation and rule out or pinpoint it AS a problem, so you can move on. In lieu of the oil (for the test period) try the other end of @GRMPS 's carpenter's pencil and "color" the entire underside of the sprue plate, OR, if you're a welder, use a soapstone marker. These may not be your favorite method, but can let you cast without the 2-cycle oil long enough to rule it out (or in) as part of the problem. Any more, the moulds I have left all get the soapstone on the sprue and 2-cycle on alignment pins only. Just seems to work best for MY moulds, so I'm not suggesting ths as a complete or permanent fix, but something t o get you by if you omit the 2-cycle on the sprue plate long enough to see if it's part of the problem.

STAY AWAY from the edges of the sprue holes with the pencil-lead, especially on the aluminum sprue plates. Easy to knock the sharp edge off the aluminum with the "lead" in the pencil. The soapstone is safer, works better for me and a small piece will last for eons.

 

[JonB]

OK, thinking this through...a thorough cleaning (first with solvent, then dish soap) and maybe a touch of smoke from a butane lighter...but not today, it's too dang nice out. I think a trip to the county fair is in order.

 

[JonB]

I'm thinking "burrs" too, even though you can't see them. I went thorugh this on my own most recent mould. My last Arsenal mould got the normal toothbrush (M16 cleaning brush)/Dawn/HOT water/Barkeep's Friend/hot rinse/BOILING rinse treatment. That USUALLY is enough to knock off burrs I can't see, but not this time. I had to give it a second "go" with extra emphasis along the edges of the cavities. After that it was OK. It initially took some casting to move/raise the little burrs such that they became a nuisance, so the problem - SYMPTOMS were the same as what you're experiencing. This is not normal for Arsenal, by the way. This one had a couple minor irritations, but I think he was struggling to keep up with demand. They are WAY nicer out of the box than any LEE I've bought, even though the last few LEEs I bought were actually almost impressive.

If the 2-cycle oil is haunting your conscience, eliminate it from the equation and rule out or pinpoint it AS a problem, so you can move on. In lieu of the oil (for the test period) try the other end of @GRMPS 's carpenter's pencil and "color" the entire underside of the sprue plate, OR, if you're a welder, use a soapstone marker. These may not be your favorite method, but can let you cast without the 2-cycle oil long enough to rule it out (or in) as part of the problem. Any more, the moulds I have left all get the soapstone on the sprue and 2-cycle on alignment pins only. Just seems to work best for MY moulds, so I'm not suggesting ths as a complete or permanent fix, but something t o get you by if you omit the 2-cycle on the sprue plate long enough to see if it's part of the problem.

STAY AWAY from the edges of the sprue holes with the pencil-lead, especially on the aluminum sprue plates. Easy to knock the sharp edge off the aluminum with the "lead" in the pencil. The soapstone is safer, works better for me and a small piece will last for eons.

You make a good point...also all bullets are sticking "ONLY" on the Right side mold half. If my theory of residue was correct, I'd suspect I'd have more random sticky cavities (on both mold halves)...of course, the residue could be adhering to slight burrs that didn't give trouble, until the residue built up enough to cause the problem?

 

[Jeff H]

OK, thinking this through...a thorough cleaning (first with solvent, then dish soap) and maybe a touch of smoke from a butane lighter...but not today, it's too dang nice out. I think a trip to the county fair is in order.

I like to boil a kettle of water while doing the dish-soap wash and, after the hot water rinse - pour the whole kettle of boiling water over the halves as they lie on a vinyl mat in the sink. Pour some, turn them, pour some, turn them,.... They get HOT, but I sometimes forget. Lift the halve out and put them on a cooling rack and they will dry by themselves. The boiling water gets all the residual oils/solvents off. Or maybe it's part of my personal casting superstition, but I keep doing it anyway.

I do have special privileges in the kitchen and access to those tools though and some may not. My raspberry scones get me some great mileage/latitude. Still not allowed to operate the automatic dishwasher though.

 

[Ian]

A flattened and filed .223 case mouth used as a scraper and a high-powered lens (like the 20x pocket microscope that comes with the Lee hardness tester kit) used to see what you're scraping is a pretty good burr removal method. Look first, very carefully, and see if anything protrudes into the cavity. Ignore the furrow of metal raised on the mating face of the mould halves because if you remove that you will get exaggerated parting line impressions on your bullets. Just make sure that furrow isn't rolled INTO the cavity.

Another issue is lead sticking to the top and bottom of the lube groove shanks near the parting line. This seems to accumulate if you cast hot and don't lightly smoke the gummy aluminum moulds and creates a keystone-shaped end to the lube groove form which locks the bullets in the cavity.

I'm still trying to figure out why this started after a long preheat. I don't belive I've ever seen oilbir even oxide residue cause bullets to stick. It's a mechanical lock of some kind, either cavities machined off-center to the parting line, burrs, warpage at the cavity edge, lead buildup, or some other physical issue regarding draft.

 

[Joshua]

I have a Lee 6 cavity that had two cavities that were sticking pretty hard on one side. I had used toothpicks looking for burrs, and scrubbed it with soap & water. Then tried smoking it, which helped a little. But, they were still sticking.

I ended up scrubbing that mold with Bartenders Friend and a toothbrush about 4 or 5 different times. Over the time period of a few different casting sessions.

I also took a stone to the top edge of the mold. That helped a few of the bases fill out better.

It now works great. I don’t know if it was the light stoning of the top edge or all of the cleaning with the Bartenders Friend (abrasive cleaner). Probably both helped, it was grabby and now it ain’t.

 

[Jeff H]

.....Another issue is lead sticking to the top and bottom of the lube groove shanks near the parting line. This seems to accumulate if you cast hot and don't lightly smoke the gummy aluminum moulds and creates a keystone-shaped end to the lube groove form which locks the bullets in the cavity.............

Ian, this is a new one for me - and maybe sometimes my subsequent and exuberant scrubbings removes it. Maybe?

Can you SEE this problem, or do you identify it by having eliminated other possibilities/experience, other?

 

[Ian]

You can see it, it's just like lumpy lead in a barrel throat. Can't right mow but maybe later I'll see if I can find some on a mould and photograph it.

 

[GRMPS]

You can test for burs by rubbing a q-tip or cotton ball around the cavities

 

[fiver]

fix the lip on top of the base band.

 

[Spindrift]

The strange thing about your problem, is the fact that you have cast so many bullets with no problems before this problem made itself known. It would seem logical that a mechanical/geometrical problem with the cavities would have bothered you from the start. Maybe something happened with your oxidation layer? I would just smoke it with a butane lighter, to begin with.

Have you been using the same handles? A couple of times, I have had mould problems that resolved with a slight adjustment of the nut on the handles (usually loosening a tad). The mould halves need just the right amount of play, to self-align properly upon closing.

 

[JonB]

Same handles, in fact I haven't removed them since the first session, because I haven't cast anything else that uses the Lee 6 cav handles since. I do normally remove handles, as I store molds without handles attached ...but since I intended to cast more, I left the handles attached. I do have two sets of well worn loose Lee 6 cav handles that get used...and the handles I've been using are the most worn and loose, in fact I plan on re-gluing the wood back on them.

 

[Jeff H]

...........A couple of times, I have had mould problems that resolved with a slight adjustment of the nut on the handles............

I think "adjusting the nut on my handles" would have covered any previous issue as well!