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01-22-2010, 07:33 AM   #1
Mo deller

Join Date: Mar 2009
Posts: 212
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PTFE

I have a scrap box of plastic and was wondering if there is a positive way of identifying ptfe.

Peter

01-22-2010, 07:51 AM   #2
Noitoen

Join Date: Dec 2008
Posts: 621
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Re: PTFE

PTFE is a dull white, feels soapy, and is denser/heavier then other plastics.

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Regards,

Helder Ferreira from Setúbal, Portugal, (Europe)

01-22-2010, 09:07 AM   #3
rickharris

Join Date: Jan 2008
Posts: 313
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Re: PTFE

FWIW

Density PTFE (lb/in³)
unfilled 0.078 25% Glass filled 0.081 25% carbon filled 0.075

(g/cm³)
unfilled 2.16 25% Glass filled 2.25 25% carbon filled2.08

Same for Polyethylene

Density (lb/in³)
LDPE 0.033 HDPE 0.035 UHMW 0.034

(g/cm³)
LDPE 0.92 HDPE 0.95 UHMW 0.93

http://www.boedeker.com/ Useful site with lots of information
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I am confused

01-22-2010, 02:59 PM   #4
Mo deller

Join Date: Mar 2009
Posts: 212
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Re: PTFE

I have some that is I would say milky white and does feel a bit slippy to touch. I would guess it is ptfe but I have no experience so wondered if I could be fooled by something similar.

Rick, I dont know what to do with all the numbers. I guess there must be a formula to work it out from weight and volume but I have no idea how to do it.

Thanks
Peter

01-22-2010, 04:03 PM   #5
Noitoen

Join Date: Dec 2008
Posts: 621
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Re: PTFE

The numbers are easy. Just fill a graduated measuring cup with some water, drop a chunk of the material you want to measure, determine the water displacement in cu/in, weigh the piece and calculate the density.
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Helder Ferreira from Setúbal, Portugal, (Europe)

01-22-2010, 05:15 PM   #6
Mo deller

Join Date: Mar 2009
Posts: 212
Liked 8 Times on 8 Posts

Re: PTFE

Yes I can do the drop it in some water and weigh it bit,it's the calc I dont understand. What is the formula?

01-22-2010, 05:56 PM   #7
Mo deller

Join Date: Mar 2009
Posts: 212
Liked 8 Times on 8 Posts

Re: PTFE

Ok I think I have it. Mass divided by volume = density. I get the impression that's very basic and in reality it is more complicated.

02-04-2010, 06:56 PM   #8
solver

Join Date: Jan 2010
Posts: 42
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Re: PTFE

How about simple rubbing-test? If it's ptfe, it should be quite slippery against for example brass or steel.

02-05-2010, 12:56 AM   #9
charlesfitton

Join Date: Jan 2010
Location: Maryhill ON Canada
Posts: 163
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Likes Given: 466

Re: PTFE

A technican at my place of employ showed me a neat way to identify plastics
- a burn test.

Some won't stay lit, some smoke a lot, some drop small burning gobe of fire - I'm sure there's a chart somewhere on the web.

Marry up the characteristics with the chart and Roberts' married to your Auntie...

f
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02-05-2010, 02:24 PM   #10
Mo deller

Join Date: Mar 2009
Posts: 212
Liked 8 Times on 8 Posts

Re: PTFE

I just had a google and found that if I poke a soldering iron into ptfe it doesn't drip and should smell of burnt hair.
Added to feeling slippery I think should get some positive id there.

Many thanks
Peter

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