Wrinkles?

[David Bachelder]

I have a LEE .358 X 125 grain 6 cavity mold, aluminum. I cast Lyman #2 alloy at 700 to 750 degrees F. I get a lot of wrinkled looking bullets (improper filling). Most of the time this indicates the need for tin. However the Lyman #2 is 5% tin, so I assume tin isn't the problem. I do preheat the mold.

Can any one guess why?

I have a steel Lyman 4 cavity .358 X 158 grain mold and I do not see this problem using it.

 

[zippy13]

How about moving this one to the bullet casting sub-thread...

 

[Unclenick]

Will move to the bullet casting forum.

Did you clean and degrease the mold carefully before starting to use it? Removing the cutting fluid traces left on it is critical. Otherwise, the most common problem is the mold isn't hot enough, and raising the temperature of your alloy a little is the easiest cure for that.

 

[Rangefinder]

My immediate guess would be that you need to thoroughly clean the mold. Scrub it with a toothbrush and dawn soap with HOT-HOT water. The tiniest trace of oil in the cavity with give you bad fill-out. Beyond that, I'd go with Unclenick's other recommendation--mold isn't coming up to operating temp. If neither of those do the trick, have a look at your vent lines. Pay attention to where the wrinkles are in relation to the cavity--that could give you a clue as to where to start looking for the issue.

 

[snuffy]

A lee six cavity with small 358 boolit cavities, will need a lot of pre-heating to get well filled out boolits. Just dipping the corner of the mold in the alloy is NOT enough. Pre-heating on a hot plate for 20 minutes @ 400 degrees, is barely enough. One way to tell if it's hot enough is if all 6 sprues cut easily when the cam handle is swung to the right.

Cleaning is another thing done wrong many times, not clean enough is the problem. My method is to dunk the entire mold under boiling, very soapy, water. Boil it for at LEAST ten minutes, fish it out with tongs and hold under very hot tap water to rinse. The cutting coolant used while the cavities were being machined is very difficult to remove. heat and strong soap is what it takes. BTW Lee molds are not cherry cut, they're bored in a lathe.

 

[m&p45acp10+1]

I am with snuffy on the cleaning issue. Also smoking it afterwards will help as well. I do not use matches though. I use a burning candle. The smoke from the candle flame will leave a nice thin layer of carbon.

Also try preheating the mold. I heat mine up on a burner of my gas stove. Once I started doing this my rejects pile went from a couple of hand fulls. Down to just a few.

 

[Edward429451]

I have found that rubbing alcohol cuts thru that cutting oil very well. If none of the above suggestions work then try adding 18" or so of solder to the pot.

 

[reloader28]

DO NOT add more solder.

The OP said he was already using 5% tin. That stuff is too expensive. If it dont work with that much tin, the mold is screwed up. Scrub the mold clean and cast faster.

I make thousands of boolits every year and except for a handful of hunting or self defense boolits, they are all straight WW alloy with no tin added.

 

[Edward429451]

Thats funny. I make thousands of boolits too, and I don't care what the tin content is supposed to be, if you've ran hot then your tin can precipitate out of the melt. Adding a small pc of solder will tell you real fast if it was the tin causing your problem. If nopt, you've (gasp) wasted a pc of solder!

 

[David Bachelder]

Cleaned the mold in hot soapy water and used hot plate to preheat mold. Wrinkles are gone!

I have a Lyman mold made from steel. It is able to cast bullets with no preheating at all. I guess aluminum molds are an entirely different animal.


Thanks for the help.

 

[Unclenick]

Aluminum is, on average and depending on the specific alloys, about three times as heat conductive as iron, so it draws heat away three times faster, keeping the cavity temperature closer to the outside temperature of the block. Iron is about three times more dense than aluminum, but its heat capacity is only about half that of aluminum, so you are looking at a same-size aluminum block having 1.5 times more heat required to raise it each degree, as well as having 3 times the conductivity. Taken together, it is harder to warm up. Smoke makes a small insulation barrier, so it tends to stop heat from being drawn out quite so fast.

Be careful you don't warp the mold with hot plates and whatnot. Usually, if you set it across the top of your melt pot when you first start heating it, by the time the main mass is warm the blocks have been given a good start. Then just casting a few rounds fast will finish fringing it up to temperature. At least, that's my experience with the 6-cavity Lee .38 molds. The one that gave me trouble was the 6-cavity .32 wadcutter they used to offer. They've dropped it, and I expect mold heating problems were part of that.