Need help from boolit casters

[hondo1892]

I cast up some boolits for my 32-40 yesterday and had a lot of rejects, over half. I haven't cast anything but roundball for years. I'm a little rusty at casting boolits. I was using ww for the alloy. My boolits had tits form the vents when they filled out like they should. I know this means that there is to much force in thr pore. But when I tried to change the force the castings had rounded edges and and the base didn't fill in correctly. I also cast up some boolits from my lyman 45 colt mold and had much better success. Very few of the 45s had any metal run into the vents. The RCBS mold vents don't look any larger than the Lyman. The 32 cal. mold was an RCBS gas check. Do I need to change alloys or add some tin maybe. I'm not sure what the metal temp was as I don't have a themometer. But I set the knob on my old seaco pot at 775 degree mark when every thing melted down and I started casting. Thaks Hondo1892

[Tycer]

Try adding 2% tin to the alloy.

[Marc]

You need better venting at the base to help base fill out. I keep the sprue plate loose enough that gravity can swing it open or closed. I also take a fine cut file and break the top edges of the mold a little so you create a vent line across the top of the mold. If the lead is flowing into the vent lines you have everything hot enough so you just need better venting at the base.

[marlinman93]

If you take a file to your mold be sure to stay away from the cavity itself! You'll screw up the base of your bullet if you touch the cavity, and that's the most important part of the mold! I'd try lowering the temp slightly, and before you start keeping any bullets let the first one sit in the molds for a full minute. This will serve to heat the mold and help the lead flow cleanly.
Once you've got the mold warm don't ever leave it empty. If you stop casting for a minute to do something else, simply leave the last bullet in the mold until you're ready to restart. Then drop it out and return to pouring. Keeping the mold warm will help any inclusions or spider webbing on the outside.-Vall

[Travis Morgan]

Are you preheating your mold? Try higher temps..

[Lefty Dude]

If you have fins the melt is to hot, & not hot enough if the edges are rounded. 775 is a little to hot for WW alloy. Also you need a Casting therometer. I would bet you pot is hotter than the 775 degree setting on your pot heat control. Lead balls are forgiving on temperature casting, Bullets are not so much.

If you buy a copy of the" Lyman Cast Bullet Handbook", many of your questions will be answered. I still refer to it often as reference.

[Chuck 100 yd]

Tin will help but sounds like the lead is too hot and the mold not hot enough.

[hondo1892]

Thanks guys. I found out that my RCBS mold has to have the handles squeezed hard to close the blocks. That took care of most of the finning. My mold was plenty hot, I just slowed my pore too much. I cast some more this evening and had much better success. I paid closer attention to everything this time. I could almost tell when I would have a bad bullit before I opened the mold. I do think my metal was too hot. I know it got too hot today. Thanks for all the insite.

[Fairshake]

All the above post are correct in the content. You should buy a thermometer. Try to stay in the 675 range . When using aluminum molds you have to go up to 775 or so for better results. The Lyman cast bullet book is a must. As you stated once you have a rhythm going the bullets will be good. For cowboy shooting, WW's and a little tin will work. Been casting since 1971 and still enjoy the art of making my own. You might want to look in on the Cast Boolits forum for more info than you can soak up. Read the sticky section and all artficles by Glen Fryxell at the LASC site. Later David

[Don McDowell]

When any of my RCBS molds start feathering, it's generally either the mold or the melt is to hot, or both.

[Travis Morgan]

Don't buy aluminum molds; theyre so problematic, you're much better off using steel at four times the price. (and I'm CHEAP!)

[hondo1892]

Thanks guy, I like the iron molds better also they take awhile to heat up but they keep the heat. I have a older Lyman cast handbook and I dug it out the other day and have been reading.