MAKE: Noise — Discuss this article

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• same here
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  bought 2 gals of muriatic acid, packaged for pool use. Used copper wire, old pennies, copper pipe but not much happened. The pennies looked to be flaking off its copper, but it just didn't look like it went into any type of solution, just floaty solids.

  Posted by damonhoxworth on March 07, 2008 at 17:12:31 Pacific Time

• same here
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  Hi,
  
  Sorry to hear you've been having a problems. I must say it seems strange. I've been using this method without issue for quite some time, and the process has been used by engineers for well over 50 years.
  
  The fact that the acid goes yellow indicates that there is a problem somewhere in the creation of the mixture - the colour should be most definitely blue/green.
  
  I wonder if one of the following might be the problem:
  
  1) There is some sort of contaminant on the copper, like a varnish or oil.
  
  2) Not all copper pennies are actually copper, some are an alloy.
  
  3) Any tin solder on pipes or wire is a source of contamination
  
  There's only a few ingredient, so it should be possible to track which one is causing the problem by switching them out one by one until it works.

  Posted by Andrew Lewis on March 15, 2008 at 19:30:51 Pacific Time

• Didn't work for me
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  I mixed 9 cups of muriatic acid and 1 cup of hydrogen peroxide. I dropped some copper tubing (pipe), some pennies, and some stripped copper wire. The solution looked more yellow than blue/green. The coffee can and soup can I put in got dull silvery finishes but nothing that would pass for copper. There was never any evidence that adding the copper caused the copper to dissolve or any reaction to take place other than the liquid slowly getting yellow.

  Posted by andyboy on March 05, 2008 at 19:27:17 Pacific Time