Doing some new parts for a new customer. A few of his parts, he doesn't
have drawings for, as they are purchased from the manufacturer of the
equipment he buys, modifies, and resells.

I have two bushings to make out of plastic, he doesn't know exactly what
they are made of. I thought MDS until I compared a sample to the
bushing. MDS from McMaster at least, is a sort of gray color and quite
hard compared to the sample. Sample part is a very dark charcoal black,
and under a microscope it looks like microscopic pits tear out of the
material in machining. Also seems to have very minute reflective flakes
impregnated throughout. It feels like Teflon, and a trial part I made in
Teflon has the right "feel" on the mating shaft. Both materials seem to
be about the same hardness. I know about Delrin AF, and it's certainly
not that.

I've never seen a black Teflon before. Almost like graphite filled...
Ring any bells?

Thanks,

Jon

On Sat, 08 Oct 2005 18:28:57 -0700, Jon Anderson
wrote:

Doing some new parts for a new customer. A few of his parts, he doesn't
have drawings for, as they are purchased from the manufacturer of the
equipment he buys, modifies, and resells.

I have two bushings to make out of plastic, he doesn't know exactly what
they are made of. I thought MDS until I compared a sample to the
bushing. MDS from McMaster at least, is a sort of gray color and quite
hard compared to the sample. Sample part is a very dark charcoal black,
and under a microscope it looks like microscopic pits tear out of the
material in machining. Also seems to have very minute reflective flakes
impregnated throughout. It feels like Teflon, and a trial part I made in
Teflon has the right "feel" on the mating shaft. Both materials seem to
be about the same hardness. I know about Delrin AF, and it's certainly
not that.

I've never seen a black Teflon before. Almost like graphite filled...
Ring any bells?

Thanks,

Jon

It exists. Google it.

I tried to use bronze filled teflon for a seal once. What a disaster.
It came highly recommended, but the thermal expansion was much greater
than the tool steel it was to seal. It invariably buckled out of its
groove and jammed. Silicone elastomer did the trick.

Pete Keillor

I've never seen black teflon, although it probably exists. I have seen
UHMW in all colors of the rainbow. Both black and white are very
common. UHMW is a similar to teflon but not identical.

On Sat, 08 Oct 2005 18:28:57 -0700, Jon Anderson
wrote:

Doing some new parts for a new customer. A few of his parts, he doesn't
have drawings for, as they are purchased from the manufacturer of the
equipment he buys, modifies, and resells.

I have two bushings to make out of plastic, he doesn't know exactly what
they are made of. I thought MDS until I compared a sample to the
bushing. MDS from McMaster at least, is a sort of gray color and quite
hard compared to the sample. Sample part is a very dark charcoal black,
and under a microscope it looks like microscopic pits tear out of the
material in machining. Also seems to have very minute reflective flakes
impregnated throughout. It feels like Teflon, and a trial part I made in
Teflon has the right "feel" on the mating shaft. Both materials seem to
be about the same hardness. I know about Delrin AF, and it's certainly
not that.

I've never seen a black Teflon before. Almost like graphite filled...
Ring any bells?


Sounds like graphite impregnated Teflon to me. I used some on a
rotary airlock once. A local gasket house was able to pour some to our
specifications.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook/index.htm

Jon Anderson wrote in news:vOKdnUX-
:

Could be Black Nylatron.

On Sun, 09 Oct 2005 04:25:01 GMT, Anthony
wrote:

Jon Anderson wrote in news:vOKdnUX-
:

Could be Black Nylatron.

Ive got some Nylatron drops and I just went out and rummaged around
til I found em..Looks very much like Jon described.

Gunner

Confronting Liberals with the facts of reality is very much akin to
clubbing baby seals. It gets boring after a while, but because Liberals are
so stupid it is easy work." Steven M. Barry

On Sat, 08 Oct 2005 18:28:57 -0700, Jon Anderson
wrote:

Doing some new parts for a new customer. A few of his parts, he doesn't
have drawings for, as they are purchased from the manufacturer of the
equipment he buys, modifies, and resells.

I have two bushings to make out of plastic, he doesn't know exactly what
they are made of. I thought MDS until I compared a sample to the
bushing. MDS from McMaster at least, is a sort of gray color and quite
hard compared to the sample. Sample part is a very dark charcoal black,
and under a microscope it looks like microscopic pits tear out of the
material in machining. Also seems to have very minute reflective flakes
impregnated throughout. It feels like Teflon, and a trial part I made in
Teflon has the right "feel" on the mating shaft. Both materials seem to
be about the same hardness. I know about Delrin AF, and it's certainly
not that.

I've never seen a black Teflon before. Almost like graphite filled...
Ring any bells?

Thanks,

Jon

Vesconite ????

http://www.vesconite.com/prod/vesconite.htm

Bill Bryden posted this on an underwater ROV group.

Thought I would pass it along.

DOC



There are several simple tests that can be performed in the home that
can assist in separating common plastics, however it is important to
realize that formulated products contain large quantities of pigments,
plasticisers, and fillers that can dramatically alter the following
properties. If possible repeat the tests on a reference sample of the
plastic so you get a good feel for the test and can compare directly.

a. Visually examine the sample, looking for recycle codes :-) While
you are at it, you can check for indications of how the plastic was
made - molded, injected, rolled, machined etc.
b. Try assessing the flexibility by bending, and look at the bending
zone - does the material stretch or is it brittle?
c. Test the hardness, try scratching it with pencils of differing
hardness ( B,HB,1-6H ) to ascertain which causes a scratch in the
plastic. Alternatively, attempt to scuff the sample with a fingernail.
d. Cut a small slither with a sharp knife. Does the sample cut cleanly
( thermoplastic ) or does it crumble ( thermosetting )?
e. Hold sample in small flame, note whether it burns,
self-extinguishes on removal from the flame, color of the flame, and
smell/acrid nature of fumes when flame is blown out (Caution - the
fumes are likely to be toxic). Also attempt to press melted sample
against a cold surface, and pull away - does sample easily form long
threads.
f. Drop onto a hard surface, does the sample "ring" or "thud"?
g. Place it in water. Does it float, sink slowly, or sink rapidly? If
it sinks rapidly, it is likely to be halogenated (PVC, Viton, PTFE).
If it sinks slowly, possibly nylon. If it floats possibly
polyethylene or polypropylene. You can ascertain the actual density
by adding measured volumes of a low density solvent like methanol
until the sample neither rises nor sinks.


Cutting thin slivers results in powdery chips ( thermosetting )
- carbolic smell in flame, self extinguishing = phenol formaldehyde
- self extinguishing, black smoke, acrid = epoxide
- fishy smell = urea formaldehyde, or melamine formaldehyde

Cutting thin slivers results in smooth sliver ( thermoplastic )
- metallic "ring", burns (styrene smell) = polystyrene (note that
high impact polystyrene may not give "ring" )
- "thud", floats, hard, glossy surface, burns (paraffin wax smell) =
polypropylene
- "thud", floats, medium-hard surface, burns (sealing wax smell) =
high density polyethylene
- "thud", floats, soft surface, burns (paraffin wax smell) = low
density polyethylene
- "thud", sinks, burns (fruity smell ) = acrylic
- "thud", sinks, burns (burning paper smell ) = cellulose acetate or
propionate.
- "thud", sinks, burns ( rancid butter smell ) = cellulose acetate
butyrate
- "thud", sinks, difficult to ignite ( greenish tinge ) = PVC
- "thud", sinks, difficult to ignite ( yellow color, formaldehyde
smell ) = polyacetal
- "thud", sinks, difficult to ignite ( yellow color, weak smell ),
draws into long threads = Nylon
- "thud", sinks, difficult to ignite (minimal flame, decomposition
but no charring), cellular structure forms = polycarbonate.


What do the plastics recycling codes mean?

The recycle codes for plastics are currently being reviewed, and new
codes (probably inside a totally different symbol ) will probably be
introduced at some point.

1 = PET
2 = High density polyethylene
3 = Vinyl
4 = Low density polyethylene
5 = Polypropylene
6 = Polystyrene
7 = Others, including multi-layer

On Sun, 09 Oct 2005 04:25:01 GMT, Anthony
wrote:

Jon Anderson wrote in news:vOKdnUX-
:

Could be Black Nylatron.

I doubt it. Nylatron machines smooth without the tearing noted by
the original poster.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook/index.htm

On Sat, 08 Oct 2005 18:28:57 -0700, Jon Anderson
wrote:

Doing some new parts for a new customer. A few of his parts, he doesn't
have drawings for, as they are purchased from the manufacturer of the
equipment he buys, modifies, and resells.

I have two bushings to make out of plastic, he doesn't know exactly what
they are made of. I thought MDS until I compared a sample to the
bushing. MDS from McMaster at least, is a sort of gray color and quite
hard compared to the sample. Sample part is a very dark charcoal black,
and under a microscope it looks like microscopic pits tear out of the
material in machining. Also seems to have very minute reflective flakes
impregnated throughout. It feels like Teflon, and a trial part I made in
Teflon has the right "feel" on the mating shaft. Both materials seem to
be about the same hardness. I know about Delrin AF, and it's certainly
not that.

I've never seen a black Teflon before. Almost like graphite filled...
Ring any bells?

Thanks,

Jon

Jon,
Is it machined or molded? If molded, cut a small sliver and
burn it to see if it smells like candle wax. If so, it could be molded
UHMW from Diversified Plastics in Missoula, MT. They grind a variety
of UHMW products and mold into a variety of parts and look very much
like your description. Good luck.

Tom..............

On Sun, 09 Oct 2005 10:26:38 -0500, Wayne Cook
wrote:

On Sun, 09 Oct 2005 04:25:01 GMT, Anthony
wrote:

Jon Anderson wrote in news:vOKdnUX-
:

Could be Black Nylatron.

I doubt it. Nylatron machines smooth without the tearing noted by
the original poster.

Filled or unfilled? Is it only available as unfilled?
The material in question seemed to be filled with something.
--
Cliff

Tom wrote:

Is it machined or molded?

Both bushings are machined. I've compared to MDS, UHMW, and virgin
Teflon. Teflon is by far the closest match. Did find a company, Enflo,
late last night. They sell PTFE filled with a variety of substances,
including both carbon and graphite. I'm leaning towards graphite now
that I know it's available, just need to determine the % fill.

Thanks,

Jon

I have some rod sold locally as "machineable nylon". It's black, and looks
like the stuff described in the original post.

Steve R.



"Gunner" wrote in message
...
On Sun, 09 Oct 2005 04:25:01 GMT, Anthony
wrote:

Jon Anderson wrote in news:vOKdnUX-
:

Could be Black Nylatron.

Ive got some Nylatron drops and I just went out and rummaged around
til I found em..Looks very much like Jon described.

Gunner

Confronting Liberals with the facts of reality is very much akin to
clubbing baby seals. It gets boring after a while, but because Liberals
are
so stupid it is easy work." Steven M. Barry