Mold Release, Lee Aluminum Molds, Frustration

  • Last Post 22 May 2010
Bongo Boy posted this 07 March 2010

I'm really frustrated.

I started out this evening ensuring my Lee mold was clean and neat, and sprayed it with what was probably a little too much Frankford Arsenal mold release. After it dried and the mold was heated, i rubbed my leather gloves across the faces of the mold halves to try to ensure I hadn't filled the airways, etc.

So I pounded out about 250-300 bullets or so, and things were going just okay. Still having problems with all cavities filling, and assumed this was because I oversprayed. But, no consistency in which cavities wouldn't fill, so I decided mold release wasn't the problem.

By the time I got to 300 or so bullets, I had basically no mold release on the bottom of the sprue plate, the bullets weren't looking that great near the base so I took a wire bore brush to the cavities to ensure they were clean. Plus, I saw a minute amount of lead beginning to build up in one small spot on the top surface of the mold--where the sprue plate would contact it.

I felt compelled to respray the mold, which was hot of course, and put a good layer on. I poured 3 or 4 molds' worth, and decided to shut down for the night. Looked like I'd gummed things up by spraying a hot mold, the bullets looked awful, and I saw no hope of having a clean mold.

Where did I go wrong, and how do I clean the molds and start over?

What's so frustrating is spending so much time to get the lead and mold up to temp where I'm getting nice bullets, only to have to do mold management at 300 bullets. I can't be doing 300 bullets then have to shut's a waste of time.

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Clod Hopper posted this 07 March 2010

I gather you are having trouble getting the bullets to release? Did you read the directions from Lee? They say to use pencil lead to release bullets. I rub pencil lead where the problem is, usually teh mold cavities. Also, It sounds to me like you need to increase the heat. I run my Lee molds very hot, especially gang molds. Happy casting.

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Bongo Boy posted this 07 March 2010

Actually getting the bullets to release has never been all that big a problem; I generally have to push them out with the glove no matter what I do. The reason for using the mold release was mostly to keep lead from 'tinning' the mold here and there. This problem is the worst on the bottom of the sprue plate, aggravated by cutting the sprue when it's still a bit too hot. Do that once or twice and I've got lead wiped across the bottom of the plate.

Based on other symptoms I had (with the ladle, etc) someone here (I apologize but can't recall who) suggested that this last batch of lead I bought may have zinc in it. While I'm diluting it by adding what I think is better lead, I'm still trying to get rid of it as quickly as possible. It could be part of the issue.

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mike morrison posted this 07 March 2010

bongo, i use anti seize grease on the bottom of my spru plates. applied with the mould hot and applied with a Q tip. only a thin coat is needed. i also put it on the top of the blocks. slight smoke from a propane lighter in the cavaties helps. also sounds like yout melt temp needs to be increased. clean cavaties and hot mould should give good boolets. i clean my moulds with brake cleaner. if you do this be verry careful. bad stuff if it gets in your eyes and you breath it. hot water, tooth brush and soap is probably the best. good luck mike

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Bongo Boy posted this 07 March 2010

This is not typical of my problems, but represents by far the worst case I've seen so far. This is after I cleaned the mold, sprayed it hot, then poured the 3-4 castings:

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Duane Mellenbruch posted this 07 March 2010

Bongo Boy wrote: Based on other symptoms I had (with the ladle, etc) someone here (I apologize but can't recall who) suggested that this last batch of lead I bought may have zinc in it. While I'm diluting it by adding what I think is better lead, I'm still trying to get rid of it as quickly as possible. It could be part of the issue. I have not had a contaminated alloy give me those kinds of problems on the mold surfaces.  It will result in poorly filled out molds though.  Checked your PM's?  Some of my reading suggests that you can add small amounts of poor alloy to large amounts of good alloy and get acceptable bullets.  Are you just adding good metal to a pot of suspect alloy?  Duane

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Dale53 posted this 07 March 2010

You are creating your own problems (no disrespect intended,here). First of all, ALL new moulds require a REALLY good cleaning. Go out in the back yard, spray the mould liberally with brake cleaner or Gun Scrubber. Make sure you get it in all of the cavities, etc. Shake the excess off, then wipe with a clean, dry cloth. THEN, use a toothbrush, liquid dishwashing liquid, and hot water and scrub the bejesus out of the mould EVERYWHERE.

Then, I pre-heat the mould. I use a hot plate, set just slightly higher than medium to heat my mould while the bullet metal is melting. Lee suggests putting a corner of the mould in the melted bullet metal. When the mould gets hot enough the metal won't stick.

The idea is to get the mould hot enough to cast well but you do NOT want it as hot as the bullet metal. About a half minute in the bullet metal (just a corner of the mould) will do the job. Then start casting.

Lee moulds require slight lubrication of the alignment surfaces to operate correctly. Also, the top and bottom of the sprue plate with NOTHING but Bullshop's Sprue plate lube. After the mould is up to heat and casting well, leave the last cast of bullets in the mould. Cut the sprue, apply a VERY small amount of lube over the top of the mould (stay a bit away from the cavities)and the top and bottom of the sprue plate. IMMEDIATELY wipe off the mould surfaces. You do NOT want lubricant on there - just a film. So, apply to a hot mould with a Q-tip. Reverse the Q-tip and wipe off with the clean end.

Now, you don't have enough lube to cause problems with fill-out and you have enough to eliminate lead sticking when you cut the sprue too soon.

Bullshop's Sprue plate lube -

I have no financial interest in Bullshop but sure do know a good thing when I see it.

Here is some more informationn on “Leementing” Lee moulds:

Lee bullet moulds can do excellent work with a little effort and some experience. I have nearly 70 moulds, iron, aluminum, and brass by most of the name brands and several custom moulds. When Lee offers a design that meets my needs I have no hesitation about buying their six cavity moulds (they are made of better material and a better design than their two cavity moulds). I also have a few of their two cavity moulds and can get good bullets with them also.

FWIW Dale53

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amb1935 posted this 07 March 2010

Maybe the sprue plate isn't perfectly level? If you flat lap the bottom of the sprue plate to remove all the rough spots on there it may help with this problem. I have three lee pistol molds and one lee rifle mold. The pistol molds release fine (the six cavity much better than the two cavities) but I have problems with the rifle mold. I'm thinking about polishing the cavities using a cast bullet and some aluminum polish.

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raytear posted this 07 March 2010

The directions that come with Lee molds say to clean them thoroughly; to smoke the cavities; to apply lube to the alignment surfaces. They do not say anything about mold prep or release agents--other than the pencil someone else mentioned.

When I have followed the directions and run the melt hot enough I get good bullets---7mm, .30, 8mm, .44

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Bongo Boy posted this 08 March 2010

Thanks to all for the tips...I'll try again from the beginning.

Last night, at least, bullet release wasn't a problem, but as things got very, very hot...cavity fill-out was getting worse and I had to put the last 50 or so bullets back in the pot because they were getting too fat. Again, another few hundred bullets that go quite well, then everything goes to hell.

Maybe it wasn't on this site, but I had at least 4 people tell me the answer to my problems was definitely to use Drop Out...especially with Lee molds. So that's what I did. Maybe I suffer from the more-is-better syndrome--the mess on my sprue plate turned out to be all graphite, not lead.

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CB posted this 08 March 2010

Lee Molds, slowly I turn, step by step, inch by inch until....

Although I do have several Lee 6 cavity molds, you get what you pay for. They are cheap and inexpensive however they do work. My 40 cal mold have made over 10K bullets so far.

I have made a new sprue plate from CR steel the same thickness as the stock sprue. The stock anodized alum plate really goes to hell in a hurry.

I use Rapine mold prep all all surfaces of the mold, even the top of the sprue to aid in getting the cuttings to drop off. I do put it in the cavities and on that mating surfaces so that the bullets are a consistent diameter.

I tip the mold on the side when I pop the sprue so the minute flecks of lead do not have a chance to get on the mold mating surfaces and top of the mold in between the sprue plate on top of the mold.

I run my pot at 800 degrees and cast thousands of very high quality bullets using this method without incident.

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canalupo posted this 08 March 2010

I own 4 lee molds. i don't have any of the problems you speak of.

1) I do NOT use any mold release or anything else on the molds.I cleaned them once when I bought them. I used dawn dish detergent to clean with a toothbrush.

2) be aware of the way Lee molds close on the bottom. I only have trouble, when the mold looks closed on the top but has a space on the bottom. I have gotten into a habit of flipping mold and tapping base together to close bottom. It seems the mold halves become canted when they get too hot.

3) not enough tin causes a lot of problems. I throw a pound of tin in 40 pounds of wheel weights for no good reason but it works for me.

4) Watch your flux any type of acid will make tin and carbon stick to steel (sprue plates included).

5) I let the mold sit in the pot until the lead will melt off before I start to pour. It seems to help.

That's the way I do it and it works for me.

Good luck

Bob D

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Bongo Boy posted this 08 March 2010

So, since everyone preps, uses and maintains these molds completely differently and yet gets good results, I'm going to randomly try stuff until I come up with my own unique method that also works. Statistically, I should reach success just a little bit more quickly than trying the above-mentioned techniques. :D :D :D


Seriously, I DO see a common theme here, and it turns out to be exactly the same theme as in making good beer:

1) Cleanliness, 2) Good temperature control, and 3) Good ingredients.

...perhaps a saying from the brewing days applies to bulletmaking: “It's easy to make beer you can drink, the challenge is to make beer you can savor."

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canalupo posted this 09 March 2010

Hmmmmm... Beer.

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CB posted this 09 March 2010

Easy Canalupo, it doesn't sound like Duff's.

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Bongo Boy posted this 09 March 2010

Jeff Bowles wrote: Easy Canalupo, it doesn't sound like Duff's. mean doesn't sound like Iron City...some of the finest beer to ever be put in a steel can.

Well, I'm not frustrated any longer...I just enjoyed a bowl of Fiber One & Duff's. What a great way to get started on a 'productive' day, if you get my meaning. ;)

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Maven posted this 10 March 2010

Bongo Boy, You mean it's not just for breakfast?  Now, about your Lee mold “problem,” I've found that graphite spray lubes and Al molds are a bad combination and now avoid them.  Assuming your mold is free of all graphite (isopropyl alcohol will remove it) and oils, try smoking the mold as Dale53 suggested and lowering the casting temp. to 750 - 775 deg. F.  If you can get by with 740 deg., by all means try it.  In addition, I wouldn't lap the 6 cav. sprue plate as it is supposed to be slightly convex.  What I do is simply to wad up a cotton shop rag and use it to smear some NRA 50/50 lube on its bottom surface once it's warm.  I do the same with the mold's top surface, but only when the cavities are filled and the sprues removed, else it seeps into them and really screws up your session.  Reapply as needed  Bullplate lube would be better, but 50/50 lube is handy and effective:  Lead deposits under my 6-cav. sprue plates are now a thing of the past.  Hope this helps!

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Bongo Boy posted this 10 March 2010

What's been suggested via PM to me is that it looks like my pot is sitting at something close to the boiling point for lead, and my mold isn't much cooler. So, I have a no-kidding thermometer on the way, and I'll go from there. :)

Could centuries old tech be much harder? I think not!

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jppr26 posted this 11 March 2010

i use wax on my moulds, i just rub some on when they are cold and when they warm up, if they give me any problems i boil them with a tiny bit of wax and then scrub them with a old tooth brush. they seem to take the wax in the tight spots and if theres some in the cavitys it burns out quick

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Bongo Boy posted this 16 March 2010

Thanks to everyone here and especially to Duane for being especially patient. It looks now as though I can cast for extended periods, getting lovely results, repeatably. Very little fuss with the molds. I wanted to say that two little factoids proved to be key: temperature range for the pot, and approximate time for the sprue to cool. This info, combined with a thermometer, has me now looking forward to the task of patiently pouring perfect plumbum projectiles.

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giorgio de galleani posted this 16 March 2010

Sometimes I used a N°#2 pencil on the top of my moulds and under the sprue plate.

Many lee,LBT and nei moulds,90% are aluminium gang moulds.

I can empty the 20 lbs RCBS pot in an hour,without effort,listening to baroque music.

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