Thread Number: 6123
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Post# 125589   4/30/2006 at 14:28 (6,542 days old) by bajaespuma (Connecticut)   |   | |
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Loved the picture! Reminded me of 1969 Consumers Reports article on washing machines with discussion of "agitators made from phenolic vs. polypropylene". Am I correct in assuming that phenolics are plastics derived from pine tar? Any relation to bakelite? What are the properties of each material and what advantages in producing a washer agitator? Also, I was always curious to note that the black plastic agitator on our GE WA-750W(1962)dulled quickly to a matte dark gray whereas the seemingly identical black agitator on her GE WA-750X(1963) stayed black and shiny to the end of its days. Is it possible that one was one material and the other another? I also vaguely remember a Maytag brochure from 1969 describing its "Power-fin agitator" being constructed of polypropylene. Were the earlier black ones also? |
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Post# 125648 , Reply# 1   4/30/2006 at 18:10 (6,542 days old) by panthera (Rocky Mountains)   |   | |
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Ken, www.wikipedia.com... has a pretty good write up on both of these plastics. At the bottom is just a quick rundown, taken from wikipedia. Perhaps relevant to our interests, "phenolic resins" are much more costly to produce and use for agitators then the polypropylene resins are. The two plastics have in common that they are well adapted to the rigors of the washing environment. They could not otherwise be more different. The phenolic resins belong to the "thermosetting" group. This means they can only be formed into shape using heat and presure once. After that they can be machined or destroyed - but not melted. The polypropylene resins belong to a second group called thermo-plastics (ok, they can also be elastomers, but that is way over my head). This group is way easier to mold, especially when such 3D stuff as an agitator vane is involved. This group softens when heated and can be melted. Not at temperatures relevant to our interests, though. A really high-quality polypropylene agitator is a quality part. Sadly, that doesn't apply to all brands. Why one agitator would stay "shiny" and another not is beyond my knowledge. Everytime someone pronounces the Bakelite group "dead" they show up as useful again. Phenolic resins in the quantities commercially produced were/are made from mineral oil or coal today. Here the brief summary of the two plastics: Phenol can be made from the partial oxidation of benzene, by the cumene process, or by the Raschig process. It can also be found as a product of coal oxidation.(Bakelite, one of the first synthetic resins to be manufactured, is a polymer of phenol with formaldehyde) Polypropylene or polypropene (PP) is a thermoplastic polymer, used in a wide variety of applications, including food packaging, textiles, laboratory equipment, automotive components, and polymer banknotes. An addition polymer made from the monomer propylene, it is unusually resistant to many chemical solvents, bases and acids. |
Post# 125692 , Reply# 3   4/30/2006 at 21:12 (6,542 days old) by spinout (Phoenix)   |   | |
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bajaespuma: You're on the right track. The agitator that remained shiny is [likely] a polypropylene unit. The one that dulled is probably a phenol resin. Thanks Panthera for the write up on plastics. |
Post# 125754 , Reply# 4   5/1/2006 at 03:57 (6,541 days old) by panthera (Rocky Mountains)   |   | |
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He Joseph, The whole question of materials used in appliances over the last century interests me. I'd love to know more about it. My knowledge of chemistry is basic (and out of date, which fits our interests here :-) Does anyone know of any articles or links on the whole topic? The whole plastic vs. metal topic or bakelite/thermoplastics question comes up a lot. I suspect one of the advantages of polypropylene would be in getting the complex form out of a mold. The relative flexibility of the material would make some forms possible which would result in a stuck or shattered bakelite agitator. |
Post# 125783 , Reply# 6   5/1/2006 at 08:15 (6,541 days old) by bajaespuma (Connecticut)   |   | |
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Which all means that they behave exactly like tempered chocolate which contracts just enough on chilling to release from candy molds. But, seriously, why would GE use two different plastics to produce the same agitator for the similar machines? They seem to do this frequently judging by the pictures of the agitators that you folks have posted on this site. Here's picture of the very same agitator from the very same washer my parents owned: |
Post# 125787 , Reply# 7   5/1/2006 at 08:20 (6,541 days old) by bajaespuma (Connecticut)   |   | |
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Post# 125788 , Reply# 8   5/1/2006 at 08:23 (6,541 days old) by bajaespuma (Connecticut)   |   | |
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Post# 125795 , Reply# 9   5/1/2006 at 08:40 (6,541 days old) by panthera (Rocky Mountains)   |   | |
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Post# 125798 , Reply# 10   5/1/2006 at 08:45 (6,541 days old) by panthera (Rocky Mountains)   |   | |
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I can well imagine GE using different plastics for the same part. For one thing, this was the era when engineering grade plastics were really beginning to be taken seriously. By the mid-60's, you had more quality polymers available to you than just the "nylon" family. And GE was a pioneer of lots of these - think of "lexan", for instance. Another possibility was that specs just called for a resin fulfilling certain requirements - and they used whatever was cheapest and would do the job. Or maybe they are all the same plastic, but have experienced different environments. Bakelite will dull or glow, depending on what it is exposed to; as tough as PP is today, there were purity problems (especially around 1973/4/5) and so on. Does anybody have a way to find out? I'd be very interested in knowing just what resins were chosen when and why. And really fascinated if it turned out that some were invented just for our washers or dishwashers. |
Post# 125802 , Reply# 11   5/1/2006 at 09:00 (6,541 days old) by bajaespuma (Connecticut)   |   | |
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I think you're on the right track, Keven. I'm beginning to wonder if GE wasn't having different plants produce agitators with different plastics to see what would "wear" the best. After all, "quality" WAS their most important product. It would be years before Jack Welch's second wife's wardbrobe would usurp that spot. |
Post# 126437 , Reply# 12   5/4/2006 at 07:19 (6,538 days old) by thirtyater ()   |   | |
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While we are on the subject of these black GE activators, how do you remove this model of agitator? My machine has this model. |
Post# 126452 , Reply# 13   5/4/2006 at 08:07 (6,538 days old) by bajaespuma (Connecticut)   |   | |
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Post# 126508 , Reply# 14   5/4/2006 at 11:47 (6,538 days old) by bobbyderegis (Boston)   |   | |
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Just my two cents, I used to fill GE's with 1/8 of the tub full of water, and use short tugs. With a little persistance, most came off. The water seems to act as a bouyancy device. Worked for me. Bobby in Boston |
Post# 126517 , Reply# 15   5/4/2006 at 13:23 (6,538 days old) by unimatic1140 (Minneapolis)   |   | |
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Post# 126578 , Reply# 16   5/4/2006 at 18:36 (6,538 days old) by thirtyater ()   |   | |
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Bajaespuma, here is a pic of my machine. I got it recently from a very nice club member. He posted a picture of it but I will repost it just in case you missed it. Here it is. |
Post# 126591 , Reply# 18   5/4/2006 at 19:23 (6,538 days old) by maytagbear (N.E. Ohio)   |   | |
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Or, innocently meant, anyway. Doesn't the "activator" cap unscrew, like a Whirlpool's Super Surgilator cap? I was never a huge fan of GE, but through my time here, I have more affection for them than I once did. Lawrence/Maytagbear |
Post# 126664 , Reply# 19   5/5/2006 at 06:03 (6,537 days old) by bajaespuma (Connecticut)   |   | |
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The activator caps on GE Filter-Flo's up to 1960 did unscrew; you could add penetrating oil then to the seat. With the advent of the spiral ramp activators in the V-12 machines in 1961 however, the Filter mount, as Unimatic refers to it, became integrated. I remember when one of the activators on one of my parents' apartment machines became stuck , the GE repair man had to saw and wrench it off. ( I'm still kicking myself for not having had the foresight to save at least the control panels on those machines before they hit the curbside.) Years later, in the seventies, the straight-vaned blue activatos for the "Heavy Duty/18" models had a blue Filter Mount that slipped off; you could then get at the top of the seat. Thanks, Thirtyater for the pics! I will look forward to more pics including, possibly, a close-up shot of those "Suds-Saver Lids Instructions". |