Help needed Lee 2 cavity molds

[dj454]

I have been casting for a couple of years now. I have been using 3 Lee 6 cavity molds along with a 2 cavity RCBS and a 4 cavity Lyman. The Lee molds I had a bit of a learning curve and I damaged one mold in the process but I have everything working like a charm now.
I decided I wanted to try a lighter bullet for 40. The 6 cavity Lee I have is a 175 grain. They offer a 145 swc 2 cavity. I figured what the heck I have this thing figured out and I have read the newer Lee 2 cavity molds are much improved. When I went to place the order they had the Lee 230 grain 300 Blackout molds on sale. I have started a 300 BLK build so I ordered 2 of those as well.
When it was time to start casting I cleaned the molds and smoked them. Then I preheated them along with the 6 cavity I was using at the time. I started casting and after 20 lbs of lead I got maybe 100 usable 145 grain 40's and no usable 300 blk bullets. The 40 mold wouldn't fill out properly on a consistent basis. The 300 blk molds never filled out properly. The bullets look like when you have a cold mold. Checking with an infrared temp gun the molds should have been plenty hot and the 6 cavity was dropping perfect bullets within a few drops as usual. What is the trick to getting the Lee 2 cavity molds to work? I suspect they are not venting properly but I can't be sure. There is nothing visibly wrong with them. Thanks guys.

[Boolit_Head]

I just happened to have picked up that same 145 mold. No problems on this end but I also am not casting with two molds at a time if that is what you are doing. You may be allowing them to cool to much? Maybe not getting the mold up to a good temp. Also how fast is the stream on your pot set? It should not be trickling into the mold. That will allow some lead to set up before it is full especially if your mold is cool.

I cast with the lead a little on the hot side and just use a single mold. Once I pour and the sprue solidifies I count to about 10 then cut the sprue. after a couple of drops the mold will come up to temp and start dropping perfect bullets. With the 2 hole molds there is not a lot of mass to store heat like the 6 bangers.

[tazman]

+1 on Boolit Head's post

[ioon44]

I have a new 145 SWC Lee mold , when I got it I just washed it out with acetone and started casting. Using 6-2-92 alloy it cast 142gr and measured .402" with good alignment.

The best way I could get to fill out was to put the sprue plate up to the pot orifice and pressure cast, I still had a large cull rate like 40%.

This is the only mold I have tried to use without smoking the cavities and have done 4 casting sessions this way.

I don't like using Lee molds for me they are hard to use compared to the NEI, LBT, RCBS & Lyman molds I have

[Boolit_Head]

I didn't think about the cleaning causing it as well. I use a tooth brush and some hand soap or disk soap and rinse well and then smoke the mold. I think getting that carbon layer in there really helps.

[MT Chambers]

I wouldn't smoke the mold, once you are done with soap and water, you really need to wash out the soap using something that leaves no residue, I use brake cleaner last.

[dj454]

I cleaned them with acetone. I followed the same procedure as I did with the 6 cavity Lee molds and they have served me well. I have always used multiple molds when casting. It sounds like fir the 2 cavity I will have to change how I cast. As far as the stream I always do a fast stream. I will try again the next time I cast and just do one mold at a time and see what happens. I sure didn't get good results using the same method as the 6 cavity. Thanks for the help.

[fcvan]

30 years ago, I smoked my molds because I thought that was the way to go. For the past ten years, every Lee mold I've bought was cleaned with hot soapy (Dawn) water and a toothbrush. I had the Lee 10lb pot warming up with a tin can lid covering the top. I set the mold on top of the lid and let things warm up. The last 12 molds I've bought, 10 Lee, 1 Lyman, 1 NOE, all dropped perfect boolits the first cast. Clean mold, mold and alloy up to temp, and casting at a steady pace to keep the temp, and I am good to go.

For many years, I cast with 2 molds at a time and ran the pot temperature to where the molds stayed the correct temp. I have since adjusted the pot temp to where the sprue cools and hardens within 3 - 5 seconds. That gives me enough time to put the sprue from the last drop back in the pot, inspect the boolits, and place them in the metal bin. I pick up the sprue/boolits with a metal spoon so I can roll the boolits on the spoon for inspection. That also ensures the boolits aren't touched because I have become an avid fan of ESPC and ASBBDT.

i used to think smoking the mold was THE way to ensure the boolits dropped free. Not so. Boolit molds can sometimes have a slight edge from baking machined and that edge can hang up the boolit. After reading about mold prep and 'Lee-menting' I took a good look at my molds by reversing some binoculars and using them like a microscope. Cleaning up the edges with wooden chopsticks helped with the sticky mold(s). When mold temp and alloy temp is right, and the mold is clean, boolits drop perfectly. Oh, and I lube the pins, mating surfaces, and a portion of the mold to and sprue plate underside with 2 stroke oil, very lightly, also using a wooden chopstick. If some oil gets in the cavity it will take some cleaning and casting to get that out. Just my .02

[John Boy]

Aluminum Molds:
* Break in the mold by heating to 350 - 400 degrees. Let cool to room temperature. Repeat 2x to 3x times more
Then when casting, heat the mold to a temperature so it takes 5 seconds to frost the sprue puddle
Any aluminum mold, including Lee multi cavity, will produce perfectly filled out bullets breaking in and casting in this manner. Over heating aluminum molds is one step away of ruining it

[Motor]

This is an awsome thread. I have used my Lee 2 cavity moulds both smoked and not. I just started using 2 new moulds. 1) 440gr .501 and 2) 210gr .410 I am thinking about cleaning out the smoke now.

The .410 is a TL and it works pretty good but barely drops .410" diameter boolits.
I had a lot of trouble with the .501" 440gr filling out and making good looking boolits. Even with good flow they were coming out like the OP describes his 40s were.

I ended up inlarging the holes is the sprue plate a little and this helped. One thing for sure at least about the .501" 440gr is it gets too hot very fast and it seems there is no way to keep it in the sweet spot temp wise while using it. It also drops small .499-.500 boolits. This mould simply seems to have too little mass.

I ended up beagling the .501 440gr mould and letting it drop slightly frosted .502" boolits.

I'll be watching this thread for sure.

[edctexas]

Many on here have tried and rejected trying to measure mold temperature with an IR thermometer. The IR reading from the aluminum mold will always be incorrect. This is due the reflectivity of the aluminum. You may get a better reading from the sprue plate with its darker color, but I have never had much correlation between a K type thermocouple reading and the IR gadget. You really need to have the molds hot to have good results. The mold needs to be over four hundred farenheit. Smoking the mold is also bad. What most molds need is seasoning. This is obtained by getting the mold hot 350-400F and cooling it back to room temp. Cycling 3 to 4 times should get you good to go. I use that 145gr Lee mold and it works quite well. I did make some boolits and twirled them in the mold with Comet cleaner (washed afterwards). That normally makes the boolits just want to fall out of the mold.

Ed C

[big bore 99]

I like to clean them out good with a toothbrush and some comet. Be careful not to break any edges. To check the venting, try cutting some strips of aluminum foil and fold them double and shim the blocks out a little. I don't see it being the venting, but worth a try.

[dj454]

Update on the 2 cavity molds. I decided to give them a try again a couple of days ago. This time I only used 2 molds. The 10mm 145 grain 2 cavity and the 230 grain 300 BLK 2 cavity. I heated them up and kept the pot temp turned up. I was able to get much better fill out and produced much more usable bullets. Being used to the 6 cavity I had previously used the same process but now I can see when I use the 2 cavity 2 maybe 3 molds at a time and the pot has to be hotter than when I use the 6 cavity. My guess is the 2 cavity molds cool much quicker than the 6 cavity but now I found a process that works. I appreciate the help. I am happy now that I know and I can buy some more Lee 2 cavity molds and try some different bullet designs and weights.

[tazman]

"I love it when a plan comes together." John "Hannibal" Smith

[GhostHawk]

I used to be a "smoke the molds" after cleaning fan. Now every mold gets a light coat or 2 of the Liquid Wrench Dry Lubricant before using. When temps are right, bullets spring from the mold. When they start getting sticky the mold is getting hot and its time to cool it a touch.

I wasn't sure, but one day I was water dropping and I stuck just the corner of the mold down into the water for maybe 3 seconds.

Pulled it out, opened, made sure water evaporated off, went back to casting, bullets went back to springing out.

I love this stuff. I bought one bottle, have treated 9 or 10 molds and have not used a thimblefull yet, more like half a thimble. 4 fl oz in the bottle it will last me the rest of my casting career. Just a little on the end of a q tip is all you need for a mold.

It also does a great job of removing the old smoke from the molds.

I did a mold washing party one day, liquid wrench arrived 2 days later. I treated my 2 worst the next day, and cast with them the day after. No wrinkles, no migrating fluids, no stains, no problems.