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macona
12-16-2010, 08:12 PM
I have a chunk of plastic from a rotor from a spin washer for semiconductor manufacturing. Its a whiteish plastic. I can shave pieces off with a knife, translucent in thin sections and is machinable. Here's the weird part. If I hold it and hit it with something is sounds like I am hitting a chunk of aluminum. It rings and sustains.

Any idea what is may be?

Liger Zero
12-16-2010, 08:18 PM
Pictures please.


Also touch the edge with a flame. Describe what happens and tell me what the smoke smells like.

BE CAREFUL.

vpt
12-16-2010, 08:30 PM
tell me what the smoke smells like.

BE CAREFUL.



hahahaha :D

randyc
12-16-2010, 08:36 PM
Might be a machinable ceramic although that material is usually fired after sizing - that suggested by the comment about the "sound". You note that it came from semiconductor processing equipment so maybe the ceramic - IF it is ceramic - was chosen for chemical inertness or chemical resistance rather than the normal desirable ceramic properties.

If it is plastic, perhaps it's boron nitride ... which usually has a "soapy" feel, conducts heat better than other plastics and has good R.F. properties (low loss tangent, fairly high dielectric constant).

Cheers,
Randy C

Evan
12-16-2010, 08:39 PM
Identify just about any plastic by following this chart.

http://ixian.ca/pics8/plasticid.gif

Evan
12-16-2010, 08:41 PM
If it is plastic, perhaps it's boron nitride ... which usually has a "soapy" feel

Did you mean ceramic, instead of plastic?

Liger Zero
12-16-2010, 08:42 PM
hahahaha :D
I have a large 3-ring binder full of plastic sample "combs" The kit is used to identify plastic materials.

One of the tests is a flame test. You look at how the material melts, weather or not it ignites/burns, HOW it burns and what it looks like as it does.

You can also tell my the odor. HDPE and Delrin smell totally different. There is no mistaking PVC for Nylon.

The BE CAREFUL admonishment comes from a rather strong dislike of dripping hot plastic onto surfaces where hot plastic should NEVER go... like my skin, important documents or the cat.


EDIT: Also Even's chart. :D

macona
12-16-2010, 08:58 PM
It does burn. Kind of smell like fireworks and sooty so I am thinking its PPS.

http://farm6.static.flickr.com/5163/5267748474_a58d05131b_z.jpg (http://www.flickr.com/photos/67292116@N00/5267748474/)
Untitled (http://www.flickr.com/photos/67292116@N00/5267748474/) by macona (http://www.flickr.com/people/67292116@N00/), on Flickr

Liger Zero
12-16-2010, 09:03 PM
http://en.wikipedia.org/wiki/Polyphenylene_sulfide





An easy way to identify the plastic is by the metallic sound it makes when struck.

Paul Alciatore
12-16-2010, 09:17 PM
Identify just about any plastic by following this chart.

http://ixian.ca/pics8/plasticid.gif

Evan,

You are a marvelous source of information.

Black_Moons
12-16-2010, 09:22 PM
Very nice chunk, Looks very reusable :)

randyc
12-16-2010, 10:36 PM
Did you mean ceramic, instead of plastic?


No, although I didn't put any thought into the comment. I used the term in the context with which I'm familiar: as a major additive to engineering plastics, epoxies and the like - good thermal and electrical properties make it a highly useful one.

Casual conversation might become tiresome if we had to qualify terms that we usually take for granted (e.g. composition of "concrete", "steel", "air", "plastic" and the like).

Cheers,
Randy C

Evan
12-17-2010, 12:10 AM
Yeah but, boron nitride is a very commonly used ceramic and by itself is almost as hard as diamond. It isn't at all like plastic. Sometimes to avoid confusion it is a good idea to qualify your comments, as in boron nitride filled plastic. I did not know what your meaning was.

randyc
12-17-2010, 12:56 AM
Yeah but, boron nitride is a very commonly used ceramic and by itself is almost as hard as diamond. It isn't at all like plastic. Sometimes to avoid confusion it is a good idea to qualify your comments, as in boron nitride filled plastic. I did not know what your meaning was.

Who is confused, what requires qualification and why the argumentative attitude ?

edited to add:


Casual conversation might become tiresome if we had to qualify terms that we usually take for granted (e.g. composition of "concrete", "steel", "air", "plastic" and the like).

Evan
12-17-2010, 01:11 AM
????

I am not being argumentative. I thought you meant ceramic and instead wrote plastic. Boron Nitride is a ceramic, not a plastic.

You wrote: "If it is plastic, perhaps it's boron nitride ... which usually has a "soapy" feel, conducts heat better than other plastics and has good R.F. properties (low loss tangent, fairly high dielectric constant).
"

macona
12-17-2010, 01:18 AM
Evan, thanks for the chart. I had seen that years ago and forgot all about it. Better save it this time.

The other side does have a few grooves in it but its still a good chunk. McMaster wants $371 for a 1x6x6 piece!


Funny, I read the article on PPS and missed the metallic sound note.

randyc
12-17-2010, 01:45 AM
????

I am not being argumentative. I thought you meant ceramic and instead wrote plastic. Boron Nitride is a ceramic, not a plastic.

You wrote: "If it is plastic, perhaps it's boron nitride ... which usually has a "soapy" feel, conducts heat better than other plastics and has good R.F. properties (low loss tangent, fairly high dielectric constant).
"

Sorry, I still don't get it: what is it that you are disputing, who is confused - who is concerned or even interested in this topic (no offense) ? Amazing how this stuff gets off topic so easily !

Evan
12-17-2010, 06:14 AM
I can't see another way to explain it. I think that others can see what I meant. It really doesn't matter any more.

Liger Zero
12-17-2010, 06:21 AM
I'm going to step in here.

Plastics and ceramics are NOT THE SAME THING. Boron nitride is NOT A PLASTIC.

I cannot identify a material if I have faulty information.

One thing that bugs the **** out of me is people who cannot stand being corrected. WE ALL MAKE MISTAKES GET OVER IT AND MOVE ON.

I'm done. The material in question has been identified.

randyc
12-17-2010, 10:15 AM
"Concrete" is also not a gravel or a sand or water but those are some of the major constituents, we just don't refer to them in casual conversation. A search for "boron nitride plastics" will turn up any number of articles about the usage of the material in other compounds most of which are "plastics" by somebody's definition. In fact the word "plastic" itself is misused or misapplied when considered from the engineering definition. This whole "name that tune" obsession is totally pointless.

I've used boron nitride for forty-two years and I machined my first piece in the late sixties. It's as common as teflon in the RF field (oh sorry, PTFE, since we're focused on trivia here).

I don't care if it grows on trees or is hatched from eggs. That kind of information is useful for game show candidates, not for those who use the material on a daily basis. What I DO care about are the mechanical and electrical characteristics, machinability, cost and where to buy it. It is a soft, "soapy" material and easily machinable with anything that has an edge, fingernail file for example.

I didn't realize that a casual comment on an internet forum, in direct response to a question would be interpreted as a test of some kind. Of course these conversations frequently degenerate into "Trivial Pursuit". I hope that you find your "plastic" useful - if it IS boron nitride, and it sure looks like it, that is a costly chunk of material !

I'll be silent now so someone can have the last nitpicking word, LOL -

lazlo
12-17-2010, 10:19 AM
Jerry, what are you going to do with the PPS? Inquiring minds want to know! :)

Evan
12-17-2010, 10:39 AM
I'll be silent now so someone can have the last nitpicking word

If I look up Boron Nitride I find nothing but references to the ceramic called boron nitride. If I look up boron nitride plastic then I find references to the plastic deformation properties of the ceramic boron nitride and suppliers of boron nitride powder. A few contain references to boron nitride as a component of epoxy materials.

You may think "plastic" when you hear the term "boron nitride". It seems nearly everyone else doesn't. I think "ceramic" and "grinding wheels". You may have been working with it as a filler material for certain very specialized filled polymers but that is a very small group of people and does not inform the vast majority of people reading your comments. It is an excellent example of when an explanation should accompany an off hand reference. We aren't talking about concrete.

Ian B
12-17-2010, 10:52 AM
When I saw "boron nitride", I also thought of the cubic version, with near-diamond hardness. Seems there's also a hexagonal form, that's similar to graphite. This is the stuff used as a filler in some plastics, and it lubricates in a similar manner to graphite filled plastics.

http://www.advceramics.com/downloads/documents/81502.pdf

which sounds like the stuff that Randy was describing.

Until I read this thread, I had no idea there were different sorts.

Ian

Liger Zero
12-17-2010, 12:10 PM
. In fact the word "plastic" itself is misused or misapplied when considered from the engineering definition.


QFT. This bugs me no end but I seem to be the only one who gets it. PLASTIC is a state of matter, not a material. :)




This whole "name that tune" obsession is totally pointless.


Indeed.



I'll be silent now so someone can have the last nitpicking word, LOL -

Discussions like this power the internet. Now if you excuse me I'm off to argue Star Trek with other "fans" who "enjoy" the show. :D

macona
12-17-2010, 12:33 PM
Jerry, what are you going to do with the PPS? Inquiring minds want to know! :)


Not sure yet. I did look up the specs and it is one of the lowest outgassing plastics available so I can use it for parts in my vacuum system. It also has a real high dielectric strength at 18kv per mm so it could be used for insulators and supports.

Cobbler
12-17-2010, 12:45 PM
Serious question..... why is Polyester listed on both sides of this identification chart?

Evan
12-17-2010, 01:15 PM
Polyester can be made as a linear molecule compound in which case it is a thermoplastic and will melt when heated. It can also be made as a cross linked thermoset plastic in which case it does not melt when heated. That is the first step on the chart to determine what you have.

Tim in D
12-17-2010, 01:55 PM
The Boron Nitride I'm familiar with must be the "hexagonal" variety. It's soft enough to machine readily, white in color and can withstand high temps. Used it in RF induction heating and glassblowing fixtures. Feels smooth but not soapy like talc. Machines to a powder.
Tim in D

gwilson
12-17-2010, 01:57 PM
Randy is being a jerk. If you are discussing TECHNICAL items,correct words are mandatory.

Liger Zero
12-17-2010, 02:29 PM
Randy is being a jerk. If you are discussing TECHNICAL items,correct words are mandatory.


That's a bit harsh. Lets call it "stubborn." Holiday spirit and all that.

newkidka
11-15-2012, 02:57 AM
Hello Randyc.

I am an electrical engineer from Israel and I've been searching (for really, quite a long time) where can one purchase a compound that is made of 20% boron nitride & 80% Teflon. This compound is for a high power RF component.

I noticed your comment on the thread "What is this odd plastic" suspecting it is Boron Nitride.

I was wondering if you could help me and share your knowledge of where to buy such a compound. (The compound needs to be made into plaques with the following dimensions: 130 X 110 X 2 mm, or with similar dimensions).
Any information would be useful!

Sincerely,

kidka


P.S. I tried sending you a private message, but it seems your 'private message box' is full :)



Sincerely,

Dan ("kidka")

Ian B
11-15-2012, 04:04 AM
Here's a downloadable .PDF of Evan's identification chart: http://www.consultekusa.com/pdf/Tech%20Resources/New%20ID%20chart%20.pdf

Ian

A.K. Boomer
11-15-2012, 08:37 AM
At any rate, what a great chart Evan... :)

Now all's we need is one like that for our "mystery metals"....

Evan
11-15-2012, 05:19 PM
Nice to find the original source of the chart. I found it elsewhere and the quality wasn't very good. This one is in vector format which makes it much easier to read if printed on two pages, which it needs.

HWooldridge
11-15-2012, 08:14 PM
I worked in the plastic injection business for almost 20 years and we used the chart that Evan posted to get a general idea of a material's ID. One thing that can cause a ringing sound in several materials is the addition of fiberglass but the flame and smell test is pretty accurate - especially if you have a known standard to compare against.