Greetings:

I just got done turning about 300 pounds of wheel weights into ingots. I started casting some bullets for my 45-70, but I am having a problem with the mold fill-out. I am not getting nice square corners on the lube grooves, but more rounded. I beleive this to be due to the fact that there is not enough Tin in the alloy. Where can I get ingots of tin, if this is the problem. Any help will be greatly appreciated.

Justin Korpal
920-471-8008
shooters forum member K0RPL

Run the melt hotter and pre-heat the mold...back down on the temp. only when the bullets are coming out frosted. IF that doesn't fill them out, then can try to add some tin.

Tin seems to change the surface tension of lead..making it flow more easily. Running the mold and alloy hot does tend to fronst bullets a bit...but so far, unless the frosting is big and grainy, a little light frost has never seemed to hurt a thing.

Doesn't take a lot of Tin to get this effect, and whelle weights usually have a little bit in them... so you'd proably not use very much extra.

Justin
What make of mold are you using?
How well de-greased is the mold?
If you have a magnafying glass take a look at the vent grooves of mold. Sometimes with new molds there's a blockage from the machining that sort of smears across the vent lines.
While you are using the magnafying glass take a look and see if there is any debre in the grooves. I use one of the pointed wooden shish-ka-bob sticks and scrape out each line just to be sure. Check the sprue plate and top of the mold for any crud.
Hold the mold up to the light, closed as if ready for casting, and see if there is light showing between the mold halves and how tight the sprue plate is.
If I've asked questions that you've already checked out or know about, please excuse my presumpiousness.
Jim

Arkypete:

Thanks for all of the help.

To answer your questions, I am using Lee Bullet Molds. I casted about 200 45-70 340 grain flat point bullets yesterday with no problem. They were filling out properly. This morning I turned about 350 pounds or so of wheel weights into ingots. I was using a the same ingots yesterday with no problem, but I was running the lee Pro-4-20 lower today then last night. I will try that as well. I did de-grease the molds with acetone, and then I lubed them with bullet lube as lee says to do with all molds. I have never had a problem with any of my lee molds. I think tommorrow night I am going to run the melt hotter, and then turn it down after they start to frost. Thanks for all of your help. I do think I want to pick up a couple of ignots, so I am going to look around and see where I can find some. Any help would be appreciated.


Justin Korpal
920-471-8008
shooters forum member K0RPL

This isn't really related to your problem, but though I'd toss it in for accuracy. Tin. Tin does one other thing (besides increasind hardness a little bit and making the lead flow easier)...it lowers the melting temperature of pure lead.

Without meaning to, that lower melting temperature has about the same effect as running the lead hotter...same temperature setting on the pot, but becasue it melts ealier, it's going to flow a bit better becasue it has to cool to a lower temp. to solidify...so part of tin's improvment in casting is kind of "hidden".

Think you can get your molds back to working with just upping the pot's temperature for the same reasons...lead takes longer to solidify, so it froms to the mold's smaller details before it freezes.

I found a local hardware store that can order 1# bars of 50/50 lead/tin. My rifle bullets have all been cast with 50/50 wheelweights/linotype but I do use 90/10 wheelweights/tin for my pistol bullets. The tin does allow good fill without needing to run the pot hot. The 90/10 mix also produces a bullet that weighs exactly what the Lee mold advertises as that mix is their "control" alloy. The bullets are really pretty.

I think I bought the bars for about $5 a bar but that is the only place I could find tin locally. MidwayUSA offers a number of alloy choices including tin but with shipping the cost is up there.

Justin
I've got a buddy who travels a bit. He has had really good luck coming up with bar soldier and linotype in scrap yards and recycling centers.
Check out old pewter.
The new pewter may be aluminum, but some maybe mostly tin. Wife had some fancy metal decorations, sort like a short section of bracelet, on a pair of jeans she purchased. They were bright, shiney and appeared to have been cast. When dropped into the pot it disappeared.
Jim

1 to 1.5% tin is all you really need to get the good effect of the tin, more that that just adds to the cost of the bullet unless you are making a plain lead/tinalloy like 20:1 or 16:1, but WW with 1.5% tin will do anything those will and it's generally cheap. Frosting won't hurt a thing, and you are like most folks, you'll find that bulelts that are evenly frosted are generally more consistant is size and weight and fill out than those that are cast on the cool side. Grainy frosting is to be avoided (too hot or too fast) but a nice grey tone rater than a shiney silver is the place to be. It has been my experience that this temperature range is where Lee molds really come alive.

If the poblem started after melting a new batch of wheel weights, there is a good chance that you had some that were Zinc. That is what Zinc does, increase surface tension and results in rounded corners. Thats why Zinc is pressure cast!

If that is what the problem is, there isn't a lot can be done. since it takes a very small amount of Zinc to cause problems.

I ran into this and wound up with about 30 pounds of zinc contaminated alloy. Cast a bunch of 230gr RN HP's in a Lee mold and some 200gr SWC in a Lyman mold (both .45 cal) Nothing to brag about on the pretty side, frosty gray color and nicely rounded edges everywhere. Have not shot a lot of them off the bench but at 25yds the few I did bench in the 45 acp & 45 colt shot as well as the pretty bullets from the last batch. Don't know if there would be any difference in a rifle punching paper for score but for my needs I don't have any problem with them.

BTW, if you get zinc in the pot, you'll usually start to taste it in short order. Zinc fumes are easily absorbed through the mouth, nose and skin so keep out of it. If you are to the point where it tastes like you've had a mouth full of roofing nails all day, go drink yourself anywhere from a quart to half gallon of full flavor milk, not that % crap. Pint of butter milk is even better yet if you can get it down w/o puking. Don't recall exactly what milk does but it takes away the zinc taste and poisoning symptoms which are bad news. Good ventilation is the key but if you screw up, go for the milk!

Greetings everyone:

Got to sit down for a couple of hours on Saturday, and in no time flat had 525 perfect 38 cal 158gr swc from my dual cavity lee mold. I did change my casting style though. I dipped the corner of the aluminum mold in the molter metal for about 30-45 seconds, and then started casting. I also let both of the sprues up top connect, and then let them harden. The first set of bullets was a keeper. Also forgot to mention that I did run the Lee Pro-4-20 pot at full temp. I think that solved most of my problems. Back to casting. I think I am going to try to do some for my 32 H&R mag today. I have a Lee dual cavity mold in 90 grain. Wish me luck.

Justin Korpal
920-471-8008
shooters forum member K0RPL

I use both Lyman and Lee molds and start the mold heating proccess the same way by dipping a corner of the mold in the molten lead. I still have some remelts but when the temps of the mold and lead are just right I don't have any round corners. The optimum lead temp can very from mold to mold and from session to session.