Author Topic: possible zinc contamanation, you tell me!  (Read 838 times)

0 Members and 1 Guest are viewing this topic.

Offline tree rat

  • Trade Count: (5)
  • Avid Poster
  • **
  • Posts: 128
possible zinc contamanation, you tell me!
« on: March 22, 2009, 04:52:42 PM »
500 S&W loaded with trail boss for real light loads, aprox 900 fps, in encore 20 inch barrel, cast in a lee mold.
I wanted to capture a bullet and see if there was any expansion at this velocity, range was 35 yards shot into clay dirt bank. could not locate bullet. so I set up a 7/8 inch plate steel backer thinking the bullet hit and expand and bounce back about a foot, still no go can not find a bullet. so a freind sugested to put the steel plate in the back of a card board box and try again. well I found out what was happening to the bullets--- this was VERY interesting, one shot to the center of the box. inside was the gas check only. but one inch in front of the plate, in a pattern 1/2 inch all the way around the box 90 degree from bullet path the box was shreaded! these bullets are acting like a hand grenade schrapnal when they hit even at low velocity. I beleive it is zinc contamanation , sat one on concreate and hit with a hammer and it just crumbled. I did mold these very hot and frosty.  wanted to try one on a coyote, but my calling skills suck.

Offline Lloyd Smale

  • Moderators
  • Trade Count: (32)
  • Senior Member
  • *****
  • Posts: 18247
Re: possible zinc contamanation, you tell me!
« Reply #1 on: March 23, 2009, 02:16:55 AM »
did they air cool or did you water drop them? What alloy?
blue lives matter

Offline tree rat

  • Trade Count: (5)
  • Avid Poster
  • **
  • Posts: 128
Re: possible zinc contamanation, you tell me!
« Reply #2 on: March 23, 2009, 05:39:06 AM »
air cooled ww, but there was a bunch of stick ons that were slow to melt, so not thinking about it I turned the heat up and they melted fine with my lee bottom pour 10 lb at #8 on thermostat, I usualy run on #7. do not have a thermometer. that is why I am now thinking zinc.

Offline 45-70.gov

  • GBO Supporter
  • Trade Count: (7)
  • Senior Member
  • *****
  • Posts: 7009
  • Gender: Male
Re: possible zinc contamanation, you tell me!
« Reply #3 on: March 23, 2009, 06:44:47 AM »
did  they  cast ok  otherwise??

i  was suspecting zinc  contanimation   as i was having problens  with wrinkles
when drugs are outlawed only out laws will have drugs
DO WHAT EVER IT TAKES TO STOP A DEMOCRAT
OBAMACARE....the biggest tax hike in the  history of mankind
free choice and equality  can't co-exist
AFTER THE LIBYAN COVER-UP... remind any  democrat voters ''they sat and  watched them die''...they  told help to ''stand down''

many statements made here are fiction and are for entertainment purposes only and are in no way to be construed as a description of actual events.
no one is encouraged to do anything dangerous or break any laws.

Offline tree rat

  • Trade Count: (5)
  • Avid Poster
  • **
  • Posts: 128
Re: possible zinc contamanation, you tell me!
« Reply #4 on: March 23, 2009, 08:13:24 AM »
yes I was having some problem with wrinkles, that is another reason I turned up the heat and was casting fast. but I figured it was just the weather, I cast outside, and it was about 55 degree and light wind. it is hard to keep a mold hot enough like that.

Offline Lloyd Smale

  • Moderators
  • Trade Count: (32)
  • Senior Member
  • *****
  • Posts: 18247
Re: possible zinc contamanation, you tell me!
« Reply #5 on: March 23, 2009, 11:19:40 AM »
probably got some zinc. stick ons can be zinc too. Its normal though for lead stickons to take a bit more heat to melt too. Pure lead takes more heat. But if you had casting problems and grainy bullets good chance you got some zinc. Anymore its rare to get a batch of ww that doesnt have at least some zinc wws in it.
blue lives matter

Offline Sweetwater

  • GBO Supporter
  • Trade Count: (17)
  • Senior Member
  • *****
  • Posts: 1286
  • Gender: Male
  • When it ceases to be fun, I shall cease to do it.
Re: possible zinc contamanation, you tell me!
« Reply #6 on: March 23, 2009, 11:23:52 AM »
If it's zinc contaminated, how's the best way to get anything decent to cast? Add something? Higher heat?

I think I might be experiencing the same thing; was blaming the mold for nose wrinkles and poor fill out.

Regards,
Sweetwater
Regards,
Sweetwater

Courage is being scared to death but saddling up anyway - John Wayne

The proof is in the freezer - Sweetwater

Offline Lloyd Smale

  • Moderators
  • Trade Count: (32)
  • Senior Member
  • *****
  • Posts: 18247
Re: possible zinc contamanation, you tell me!
« Reply #7 on: March 23, 2009, 12:51:50 PM »
try adding about 5-7 percent tin and casting with your pot turned all the way up and fast enough to just keep the mold from smearing. I even keep a wet cloth to touch the spruce plate with to cool it enough not to smear. casting like that you can get good bullets.
blue lives matter

Offline Sweetwater

  • GBO Supporter
  • Trade Count: (17)
  • Senior Member
  • *****
  • Posts: 1286
  • Gender: Male
  • When it ceases to be fun, I shall cease to do it.
Re: possible zinc contamanation, you tell me!
« Reply #8 on: March 23, 2009, 01:14:00 PM »
Lloyd-
I will definitely give that a try on the next casting session. Thanks!!

Regards,
Sweetwater
Regards,
Sweetwater

Courage is being scared to death but saddling up anyway - John Wayne

The proof is in the freezer - Sweetwater

Offline Tn Jim

  • Trade Count: (0)
  • A Real Regular
  • ****
  • Posts: 714
  • Gender: Male
Re: possible zinc contamanation, you tell me!
« Reply #9 on: March 24, 2009, 04:50:13 PM »
I thought zinc melted at a lot higher temp than lead and WW. Am I wrong?
Not all Muslims are terrorist, but oddly enough, all terrorist are Muslims.

Offline John Traveler

  • Trade Count: (0)
  • Senior Member
  • *****
  • Posts: 1359
Re: possible zinc contamanation, you tell me!
« Reply #10 on: March 24, 2009, 09:15:16 PM »
True, zinc melts at 787 degrees Fahrenheit, and lead melts at 671 degrees Fahrenheit.  Wheel weight alloys (mostly lead) melts somewhat lower than pure lead.  That is why the initial signs of zinc contamination in a lead melt is a mushy, oatmeal like layer floating on top of the lead.  You can try skimming off and discarding most of it, but once the melt temperature is cranked up, some of it gets into the alloy.

According to the NRA advisor, once a bullet melt is contaminated with molten zinc, you can never get all of it out, and it would be best to discard the melt, clean the pot, and start over.  That has been my experience too.  Once a batch pours poorly in clean, hot molds, if it fails to fill out even after increasing tin content, I pour it out and start over.
John Traveler

Offline rangerwillie

  • GBO Supporter
  • Trade Count: (29)
  • Avid Poster
  • *****
  • Posts: 178
Re: possible zinc contamanation, you tell me!
« Reply #11 on: March 26, 2009, 10:34:52 AM »
Is there any real harm or damage to the mold or your barrel?

Offline stubshaft

  • Trade Count: (8)
  • Contributor
  • ***
  • Posts: 489
  • ROA's Rule
Re: possible zinc contamanation, you tell me!
« Reply #12 on: April 02, 2009, 01:14:27 AM »
Some of the stick on weights contain zinc.  The biggest culprit is usually the european weights they are notorious for containing zinc.  The last time I had this problem, the only thing that I could do waas to throw away the melt and sand blast all remaining traces of lead in the pot (I tried just dumping the melt and remelting known good lead.  It turned to slush from the remaining zinc).
Good luck.
If I agreed with you then we would both be wrong.