Scrap plastic as Blasting Media worth more than copper

[QUOTE=miked;262346]I read this and put it together with your comments on the keyboard Mylar with silver discussion on another thread. Without doing any testing my imagination brings me to what I believe are similar conclusions.

Originally Posted by alloy2

Precious metals refinery’s use abrasives on some of their processes, on old gold china that has gold guiding you will see that some of he gold has worn away just from being handled by humans. Silver plated cutlery often badly worn, the more expensive silverware usually plated over with rhodium.

Soon we'll have newattitude blasting gold guiding from chinaware

Using mechanical means to separate the silver from the mylar can end up with the silver being transferred to other unwanted surfaces. Using a water soluble material delivered by water pressure seems to be a possible great answer. Of course I am certain other parts of the process have to be adjusted.

Originally Posted by alloy2

No this is no so, the conductive silver Ink has a binder agent to assure the ink will bond with the substrate when it's applied wet, once dried the binder is of no further use. Ink removed from mylars will stay in it's new powder form. Static electricity may cause the powder to migrate to unwanted places, water will discharge the static.

Rather than chopping the mylar into small bits it could be left whole and each sheet blasted quickly(perhaps).

Originally Posted by alloy2

Chopping or shredding the mylars highly recommended, I would tumble the pulp with out an abrasive dry with out water during the initial process. Your tumbler barrel should be totally enclosed, once the process has been completed this is when you may want to dampen the pulp with water to keep the silver dust under control. Also this would rinse off any residue silver free from the pulp.

It may even be possible that mylar plastic floats in water then you could skim the plastic off leaving your silver to settle on the bottom of your tub.

I am interested in how you might envision a process to remove perhaps solder traces so components could be easily removed and processed separately.

Originally Posted by alloy2

A sandblasting cabinet to remove components from boards would be work, just change or overlay a screen on the bottom rack of your blasting cabinet that would only allow the blasting media to pass through. If there was any gold plating on the boards its coming off with the solder.

Modern solder used on electronics is about 95% tin, your recovered tin has scrap value. To maximize profit I would sell my tin scrap on ebay to be used as bullet or sinker casting material..

On a side note tin solder is the death of modern day electronic devices, tin whiskers grow on the circuits causing shorts. Already there are many multi million dollar satellites in orbit rendered useless because of tin whiskers.

NASA on tin whiskers, some good info, NASA Goddard Tin Whisker Homepage

Originally Posted by alloy2

Another NASA Whisker Failures

Commercial Satellite Failures
Military Failures
Medical Failures
Industrial/Power
Computers
Anecdotes

Catch the read on Industrial power where tin whiskers caused a nuclear power plant problems.

One of the main benefits I imagine in using water/media blasting is the control of fumes into the air.

Originally Posted by alloy2

No fumes produced with blasting only dust so yes a closed environment or a combination thereof using water or cyclone.

Thanks for a great subject. Mike

Those of you that disassemble computers and servers should be wearing some sort of breathing protection, dissembling electronics inside the apartment or house could put your family at risk.

It's a well known fact that server cabinets and the rooms they occupy are full of tin and zinc whiskers.

These whiskers are light enough to become airborne particles that may enter your lungs casing respiratory problems.

Zinc whiskers in server room.Photo Gallery: ZINC Whiskers on Raised Floor Structures

The whiskers below are ZINC WHISKERS. They were found growing on the zinc-coated steel underside of raised floor tiles. In these examples the floor tiles were part of a computer room in which zinc whisker debris was shed from the floor tiles especially during maintenance activities within the data center . The conductive whisker debris was distributed around the room via the air cooling system. Ultimately, some whisker debris was drawn inside of the electronic systems (e.g., servers, routers, disk arrays) operating in the data center resulting in catastrophic and/or intermittent short circuit failures.