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-

[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/sho...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/sho...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.