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Bakelite
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Posted by: nishedha Post Reply
09/30/2010, 09:53:29

I would like to know whether Bakelite is always opaque or can be also translucent. Thank you.



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Many colors and transparencies seen in phenolic plastics
Re: Bakelite -- nishedha Post Reply Edit Forum Where am I?
Posted by: Rosanna Post Reply
09/30/2010, 13:05:10

There is a good Wikipedia article on Bakelite.

My perspective is that Bakelite "mostly" refers to the opaque, dark reddish brown phenolic plastic invented over 100 years ago, and used for electrical insulation, other industrial uses, and household items like knobs on radios and cabinets. In the 1920 time frame, the Bakelite company, as well as many other plastic companies, started making a lot of phenolic plastics in a wide variety of colors and transparencies, including marbled versions. Since unmodified phenolics are yellow to dark reddish brown, a lot of plastic beads in this color range are called "phenolic" or even "bakelite" but I'm sure other plastics have been used to make the same color beads.

Phenolic beads will be denser than other plastics, and if rubbed or heated will in theory give off the distinctive putrid odor. I have not tried this myself on the phenolic beads I own - so I'll report back and let you know if I can tell the difference between phenolic and other amber/brown tone plastic beads.

Phenolic beads will never melt. The plastic will only burn (with a putrid odor) at a fairly high temperature. There is no way to "re-form" phenolic into a different shape- it has to be ground, sanded, drilled, etc.



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Lab report on phenolic beads
Re: Many colors and transparencies seen in phenolic plastics -- Rosanna Post Reply Edit Forum Where am I?
Posted by: Rosanna Post Reply
09/30/2010, 20:24:25

I have worked with phenolic resins many times over the course of my career in polymer materials, and I am very familiar with the odor given off by phenolics. I could not get any kind of identifying odor by rubbing my beads. I took more drastic action by mounting a diamond grit reamer on my flexible shaft tool, and reamed the holes at high speed. This produced the telltale phenolic odor, although sometimes only faintly. It was easy to get this odor on the lighter colored beads (see photo) but I had to really hit the darker beads with a lot of grinding force to get the odor from them. This finding is consistent with the fact that the darker colors are produced by curing the phenolics at higher temperatures or longer times - this makes the polymer cured more completely and makes it harder and more brittle as well. I could tell from the sawdust produced that that these were not thermoplastics (plastics that melt or deform with heat), but instead very dense thermoset (plastics that will only burn, not melt) materials.

I do not have a lot of plastic beads and could not find any amber or brown ones that I suspected were another type of plastic, for comparison.

Note: It doesn't show in the picture but one of the darkest beads is slightly translucent.

PhenolicBeads.jpg (88.7 KB)  


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Re: Bakelite And Colorful Phenolic Plastic
Re: Bakelite -- nishedha Post Reply Edit Forum Where am I?
Posted by: Beadman Post Reply
09/30/2010, 15:25:48

Scroll through the dialogue. JDA


Related link: http://beadcollector.net/cgi-bin/anyboard.cgi?fvp=%2Fopenforum%2F&tK=phenolic&wT=1&yVz=yTz&aO=1&hIz=700&hJz=600&cmd=find&by=&xcfgfs=tK-wT-yVz-aO-hKz

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And Here
Re: Re: Bakelite And Colorful Phenolic Plastic -- Beadman Post Reply Edit Forum Where am I?
Posted by: Beadman Post Reply
09/30/2010, 15:30:09

More dialogue. JDA.


Related link: http://beadcollector.net/cgi-bin/anyboard.cgi?fvp=%2Fopenforum%2F&tK=phenolic&wT=1&yVz=yTz&aO=1&hIz=900&hJz=800&cmd=find&by=&xcfgfs=tK-wT-yVz-aO-hKz

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And Here
Re: Re: Bakelite And Colorful Phenolic Plastic -- Beadman Post Reply Edit Forum Where am I?
Posted by: Beadman Post Reply
09/30/2010, 15:35:56

Quote from me:

"... there is no such thing as 'colored Bakelite'...."

JDA.


Related link: http://beadcollector.net/cgi-bin/anyboard.cgi?fvp=%2Fopenforum%2F&tK=phenolic&wT=1&yVz=yTz&aO=1&hIz=1100&hJz=1000&cmd=find&by=&xcfgfs=tK-wT-yVz-aO-hKz

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"Linkman" ;-}
Re: And Here -- Beadman Post Reply Edit Forum Where am I?
Posted by: bob Post Reply
10/01/2010, 10:20:58



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