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<p>[QUOTE=&quot;Insider, post: 4637726, member: 24314&quot;]Oldhoopster, posted: &quot;I agree that laminations can occur in improperly mixed alloys, but they can also be caused by gas bubbles/voids that are unrelated to poorly mixed allows.&nbsp; [<img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie11" alt=":rolleyes:" unselectable="on" unselectable="on" /> <b><i><span style="color: #660033">You are making me respond to the obvious!&nbsp;&nbsp; I already posted above that a lamination can occur on any coin!]</span></i></b>&nbsp; In the glass industry, seeds (partially melted raw materials) and blisters (gas bubbles) are common defects.&nbsp; Depending on the root cause, they may be related or form independently.&nbsp; Although I’m not a metallurgist, I would expect similarities between a glass melt and metal melt. [<i><span style="color: #660033">So you are an expert in glass melts but not in metallurgy yet we are going to discuss what you EXPECT?&nbsp; No thanks.]</span></i></p><p><br /></p><p>You keep saying “I want my questions answered”.&nbsp; I tried to provide answers to your question about the characteristics that led me to conclude that this can’t be an improperly mixed alloy, yet you asked it again.&nbsp;&nbsp; Do you disagree with my explanation that debonding would likely occur along grain boundaries of improperly mixed regions and not cut through differing regions due to ductility/hardness variations?&nbsp; [<i><span style="color: #660033">I agree with this; however, I EXPECT (LOL) that the other case is possible and probably rare.</span></i>] Do you disagree that varying compositional regions in the melt (or partial melt) may have different viscosities and that it would be unlikely that a gas bubble would cut through these regions and not stay in the lower viscosity region?&nbsp; [<i><span style="color: #660033">I agree with this. Technicians at the Mint told us that Hydrogen gas can get trapped in the strip.&nbsp; Since it is smaller than the other atoms in the alloy, it will EVENTUALLY migrate to the surface of a struck coin causing laminations.&nbsp; Heat adds this migration</span></i>.]&nbsp; I’m not saying those explanations are correct, but the make a lot of sense to someone who has spent nearly 30 years working in the Glass/Ceramic field.&quot;&nbsp; &nbsp; </p><p><br /></p><p>&quot;I believe I provided a reasonable explanation based on science and will be waiting for your pictures showing laminations cutting through regions of varying compositions while avoiding the grain boundaries.&nbsp; I hope you find your pics, because try as I might, I can’t think of any material science or chemistry explanations that support this.&nbsp; I know there are some chemists and metallurgists on this site and would be interested in their feedback regarding my comments, and am always willing to listen to alternate theories. That&#039;s how we learn.&quot;</p><p><br /></p><p><img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie1" alt=":)" unselectable="on" unselectable="on" /> <i><span style="color: #660033">I agree; however I am not going to let you sidetrack this discussion until it is finished.&nbsp; We are discussing the OP&#039;s coin and how the streaks were formed.&nbsp; It happens to have a lamination.</span></i> <i><span style="color: #660033">Laminations have <font size="5">NOTHING TO DO WITH ROLLER MARKS.</font>&nbsp; <font size="6">LAMINATIONS ARE ASSOCIATED WITH ALLOY ERRORS!</font></span></i> </p><p><br /></p><p><i><span style="color: #660033">It&#039;s too bad the error experts have ducked out of this discussion.&nbsp; <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie3" alt=":(" unselectable="on" unselectable="on" />&nbsp; I&#039;m curious as to how all the cents shown with bi-color &quot;dirty roller marks&quot; have their incuse lines from the rollers (on the planchet in two colors <img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie5" alt=":confused:" unselectable="on" unselectable="on" /><img src="styles/default/xenforo/clear.png" class="mceSmilieSprite mceSmilie98" alt=":wacky:" unselectable="on" unselectable="on" />) completely struck out on the finished coin.&nbsp; I&#039;m also curious why the OP&#039;s coin has streaks of different widths while the streaks on what they call &quot;roller error coins&quot; are uniform. </span></i>[/QUOTE]</p><p><br /></p>

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