Using Lee 2-Cavity Molds

[BBarn]

Been casting a few years, but only sporadically. Most of my molds are cast iron, but I also have a couple of Lee 2-cavity molds. My normal cadence seems to work well with the cast iron molds, but I seem to find my Lees overheating.

So, for those frequently using the Lee 2-cavity aluminum molds, do you:
Pause your pouring periodically to let the mold cool?
Run the lead pot at a lower temperature?
Both?
Something else?

Thanks.

[lar45]

You'll want to keep an even pace, but probably at a slower pace. Or give them a moment to cool in-between pours, but keep an even pace to keep the bullets consistent.

[243winxb]

I have a fan close by. Hold mold in front. Plus- https://www.thehighroad.org/index.php?media/casting-with-lee-molds.4127/full

[Mr Peabody]

You can keep a damp towel close by, when the mold overheats set your mold down on the towel for a few seconds to cool. A few times doing this and you'll figure out how often and for how long.

[JonB_in_Glencoe]

As 243winxb mentions, a Fan.
I have a bunch of 2 cav Lee molds. When casting with the molds with larger cavities, I have a small fan moving air over the area where I drop the boolits.

Also, always adjust your pace, instead of alloy temp, to control Mold temp. Alloy temp should be set consistently (per alloy) at about 100º above liquidus temp, depending on ambient air temp.

[Willie T]

You'll want to keep an even pace, but probably at a slower pace. Or give them a moment to cool in-between pours, but keep an even pace to keep the bullets consistent.

^This^
Slow your pace to find the rhythm that keeps mold temperature in the ideal operating window. Aluminum molds have a tighter temperature window. Keep notes on the appropriate pace once you find it as it is mold specific. Adding tin to your alloy for fill out will allow you to cast at a lower temperature and helps with aluminum molds.
Willie

[Kraschenbirn]

I use a piece of 1" aluminum tool plate for a heat sink, holding the mold against it for a few seconds before opening to drop boolits on folded towel. Speeds up hardening of pour and prevents mold from overheating.

Bill

[dondiego]

Use two or three molds as needed to maintain temps.

[Winger Ed.]

I only use a couple of Lee molds, and when mine starts to act too hot,
I leave it open after a drop and just wave it around a few seconds.
The Alum. gives up the 'extra' heat pretty quickly.

[Gray Fox]

I have also used the technique of casting with two molds to maintain a good casting temp. Depending upon my needs I'll cast two very different boolits to make it easier to sort as I dump the air-cooled ones into a towel lined Coke flat, or the water quenched into a 5 gallon bucket of tap water. GF

[Maven]

BBarn, Take a look at this, from the late BruceB: https://castboolits.gunloads.com/showthread.php?57105-BruceB-s-Speed-Casting-Method&highlight=BruceB%27s+speed+casting+method

[BBarn]

Thanks for everyone's suggestions. I'll try some of them the next time I'm using the Lee molds.

[jdgabbard]

I've tried using a damp sponge in the past with mixed degrees of success. When I notice that I'm starting to cast too hot I tap the bottom of the mold on the damp sponge to wick away some of the heat. But timing is everything with aluminum. Like you, I've always found Iron/Brass molds to have a better cadence. I But I will say that I start getting acceptable casts faster with aluminum molds.

[charlie b]

BBarn, Take a look at this, from the late BruceB: https://castboolits.gunloads.com/showthread.php?57105-BruceB-s-Speed-Casting-Method&highlight=BruceB%27s+speed+casting+method

That's how I do it. Each mold is a little different on timing. One I have I set the bottom of the mold on the wet towel for 3 seconds. If the sprue takes too long to solidify I also flip the mold and set the sprue plate on the towel for 1-2 seconds.

Another mold I only touch the sprue plate to the towel between casts.

I've tried running more than one mold and the temp gets messed up. Some molds require more cooling than others.

The other key is to preheat using a hot plate. I set the temp on mine so the mold is just a little too hot. First cast is tossed aside and then the wet towel cooling tempo works.

FWIW, this is the method I use for all my Aluminum molds, not just Lee.

[GregLaROCHE]

I often use a damp towel to cool mine down. Also, I’ll have at least an additional one to switch to if things get too hot.

[Larry Gibson]

Use two or three molds as needed to maintain temps.

Same here, especially in the hotter dry temps here in the desert. Even with 4 -6 cavity moulds I use 2 or three moulds. I also have a small fan that blows over the moulds. After pouring I set the moulds on an old machine gun asbestos glove, pick up the next mould, cut the sprue, dump the bullets, put the sprue in the pot, close the blocks, pour, then repeat.

Three Lee moulds of single or double cavity are the norm when casting. That is with normal cast bullets. With match cast bullets or specialty cast I just slow the pace down for consistent use with one mould.

[GhostHawk]

I also use a damp towel from time to time on the 2 cavity molds. The 6 cav's don't seem to have that problem.

Most sessions I will only touch it to the towel 2 or 3 times in a session to cool it down a bit.

I do tend to not run my pot hot as long as it is pouring good boolits.

[whisler]

I have the opposite problem, my solid surface hot plate won't get the mold past about 370 deg. I read somewhere that there is a fix for that but can't remember where.
I have to cast fast just to keep the temp. up.

[Hanzy4200]

The very obvious answer, which eluded me for years, is to run two molds. When the first starts overheating, swap over to the second. Simple. Some use a damp rag to cool their molds. I would suggest not doing so. It can cause molds to warp.

[charlie b]

The very obvious answer, which eluded me for years, is to run two molds. When the first starts overheating, swap over to the second. Simple. Some use a damp rag to cool their molds. I would suggest not doing so. It can cause molds to warp.

I've used a wet towel with 2 and 6 cavity Lee, 4 cavity NOE and 2 cavity Accurate molds for many thousands of rounds for a few decades now and none have ever warped from being treated with a wet towel. I've never heard of that happening. Lee even recommends the practice. The only real caution is to not allow any water to get inside the mold. If you do use a wet towel then make sure you do it before dropping the bullets, and keep the molds securely closed.

[jdgabbard]

I've used a wet towel with 2 and 6 cavity Lee, 4 cavity NOE and 2 cavity Accurate molds for many thousands of rounds for a few decades now and none have ever warped from being treated with a wet towel. I've never heard of that happening. Lee even recommends the practice. The only real caution is to not allow any water to get inside the mold. If you do use a wet towel then make sure you do it before dropping the bullets, and keep the molds securely closed.

I have heard of it happening once or twice in the past. But I’ve always considered Lee molds to be somewhat disposable. Though I’ve never had to do this with iron or brass molds. They seem to have a nicer rhythm to them. Though I have seen Lyman molds in the past that were warped. Presumably some time after a very long life since they appeared well used. Who knows, a damn towel isn’t going to wick too much away. And I’ve done it without any noticeable harm.

[imashooter2]

I have a wet kitchen sponge in an old "Daily Bread" Wilton plate. Every few pours I touch the blocks to the sponge to cool the blocks. It doesn’t take long to figure out the schedule.

[Targa]

I am a fan of the wet towel/sponge as well.

[GregLaROCHE]

I’ve cooled Lee double molds (aluminum) and steel. So far no problems. And as was already mentioned, Lee recommends it. It’s just setting it lightly on a damp cloth or sponge. Both sides are cooled equally.

[gwpercle]

When casting with Lee 2-cavity I start with dial on Lee pot at 7.5 and after pouring , long count to 5 before busting open the sprue , when they start dropping "frosty" ... I dial back to number 7.25 , fill and give 7 second lomg count before cutting sprue .

Two cavity Lee blocks have become awful small , so you have to pay attention to sprue smears ... at first sign ... slow down and clean off smears .
A fan blowing across blocks helps the cool ... fill cavities and hold block in front of fan ... long count 5 to 9 seconds (as needed to solidify sprue) ... the fan realy helps cool the blocks , I prefer it to water and sponge ...and the fan cools you too !
Gary

[Midohhntr]

Sometimes I’ll have two different molds going, just so I don’t get bored, lol. Then I can get my timing down so the boolits don’t frost.

[openbook]

Bullet size counts for what will be the best procedure to keep the mold cool. I use half a dozen Lee aluminum molds ranging from 55 grains to 405. With smaller and medium-sized molds I have a lot of success maintaining temperature by varying the size of my sprue puddle.

The 405-ers are a great candidate for the "use two or three molds" suggestion.

[Sudsy]

I have a block of steel I keep near the bench. When the mold gets too hot I rest it on the steel, acts as a heat sink. Cools it just enough and does it pretty quickly.

[Walter Laich]

I use a piece of 1" aluminum tool plate for a heat sink, holding the mold against it for a few seconds before opening to drop boolits on folded towel. Speeds up hardening of pour and prevents mold from overheating.

Bill

I do something similar: sit the mold on the stand/bottom plate of my Pro-Melt (original but probably would work with newer version).

doesn't take long to figure out how long to let the mold set