19 Jan
2009
19 Jan
'09
8:18 p.m.
On Jan 19, 2009, at 09:47:55 -0800, Chuck Guzis" wrote:
On 19 Jan 2009 at 11:17, Jules Richardson wrote:
Basically, in the US the UL is the standard which one follows (CE if
you want to go elsewhere). Failing to meet the UL/CE standards
generally has force of law in the US due to the ever diligent lawyers.
Failure to meet (and get fully tested and certified) opens one up to a
suit where one has to prove that the design is safe. Whereas, if
certified, the suer has to prove either negligence on the part of the
manufacturer or show that the certification is at fault. The latter
rarely happens. Extensions to the NEC (National Electrical Codes - a
published standard which is implemented locally) rarely step into the
areas where the UL/CE standards bear. However, some localities can't
keep their hands out of the pie...
Wall warts relieve the manufacturer of a product of having to certify
the product to the lebenty-leben, various, multitudinous and sundry
standards since the w/w manufacture does this for you. The low voltage
output eliminates all the mains testing and certification. To give you
an idea, the difference in testing and certifying one of our product
with an internal supply and one using a wart exceeded $20k and that
was over 15 years ago. Since this was a fairly low volume device you
can guess the direction we went. Even using a certified power supply
requires that the entry and attachment be certified if not provided by
the p/s manufacturer.
If one wants to be a cowboy and manufacture a consumer-level mains-
operated device without certification, make sure all your assets are
safely ensconced in a Cayman Island account.
CRC
It's always surprised me that stuff like
that's legal in the US,
given the
nature of the power outlets; it doesn't need a lot of weight for
the device
plugged into the wall to tilt slightly and risk the exposure of
live metal
contacts (heck, normal power cords and pets are a bad enough
combination :-)
Electrical safety requirements and certification in the US is a hodge-
podge of private (e.g. Underwriters Labs), state and local building
code) and Manufacturers and trade associations (NEC, IEEE "green
book"). Action with individual products is taken on a Federal level
only when a sufficient number of episodes have shown a device to pose
a danger (Consumer Product Safety Commission). AFAIK, there are no
Federal standards for electrical product safety--although there are
for RF emission.
Basically, it's cowboy electrical safety when it comes to consumer-
level mains-operated devices. 
19 Jan
19 Jan
10:39 p.m.
Basically, in the US the UL is the standard which one
follows (CE if you
want to go elsewhere).
And if something does not have a valid UL seal of approval, it does
not sell. No merchant, apart from maybe the fly by night dollar
stores, will touch a non-UL listed product.
("line", not "mains" - if you are talking US electrospeak).
--
Will
11:57 p.m.
On 19 Jan 2009 at 22:39, William Donzelli wrote:
And if something does not have a valid UL seal of
approval, it does
not sell. No merchant, apart from maybe the fly by night dollar
stores, will touch a non-UL listed product.
How many of those made-somewhere-in-China gizmos have forged UL seals
on them? Or does UL have an enforcement arm that precludes such
stuff from happening?
("line", not "mains" - if you are
talking US electrospeak).
I've seen both in US literature. "Mains" seems to be more common than
it used to be (which was not at all).
Oddly, OSHA's electric power glossary contains neither term:
http://www.osha.gov/SLTC/etools/electric_power/glossary.html
"120v distribution power?"
I like "mains" from a gloablspeak perspective, but I'm listening to
the Beeb now...
Cheers,
Chuck
20 Jan
20 Jan
7:38 a.m.
How many of those made-somewhere-in-China gizmos have
forged UL seals
on them? Or does UL have an enforcement arm that precludes such
stuff from happening?
Yes, they have audits and checks. Using the UL seal without having a
valid UL listing is probably fraud or something.
--
Will
5:01 p.m.
Basically, in the US the UL is the standard which one follows (CE if
you want to go elsewhere). Failing to meet the UL/CE standards
generally has force of law in the US due to the ever diligent lawyers.
I feel these standard, or at least the 'CE mark' is part of the problem,
and here's why....
It would apperar there are either loopholes in the standard, or plenty of
cheap electrical devices (including wall-warts) that have invalid CE
marks on them, in that I've seem enough devices that I don't consider
safe. The problem is that if the wall-wart carries the CE mark, then as
you said, the certification for the whole product becomes a lot easier,
and if there are any problems later, a large part of the defence is 'But
the wall wart met the appropriate CE standards'.
But when manufacturers were entirely responsible for what their devices
did, they made darn sure they were safe. Said manufacturers did not want
to end up paying out large amounts of damages. SO th products really
_were_ safe.
I offer as an example the PSU brick for the Philips G7000 video game.
It's a bit like awall-wart, except it has a mains input cable that you
wire to a suitale plug. But inside that brick (which is nicely screwed
together), there are no fewer than 3 protective devices. A mains-side
fuse, a secondary fuse, and a thermal fuse (on the mains side).
-tony
21 Jan
21 Jan
3:52 p.m.
Tony Duell wrote:
It would apperar there are either loopholes in the
standard,
or plenty of
cheap electrical devices (including wall-warts) that have invalid CE
marks on them, in that I've seem enough devices that I don't consider
safe.
If there were enough accidents/injuries etc. then there would be some
repurcussions for both the manufacturer that sold the wart-driven-device
and also the wart maker.
They are clearly cheap and horrible and built to a price but they must
be "safe enough" otherwise they wouldn't be sold any more.
Selling a device as CE branded when the branding wasn't properly
acquired
would clearly land the manufacturer in hot water. A defence of "well it
was
labelled, how was I to know they were dodgy" would not go down at all
well
in court. The alternative of a produce recall is pretty expensive.
That said, I _do_ dislike the fact that they are often glued together
rather
than screwed together: I've certainly rescued devices in the past by
swapping
a cable from a dead wart onto a different but power-compatible one and
that's
considerably harder these days!
I also dislike the fact that all the warts get mixed up and it takes me
ages to find the one that goes with the $foo I want to work with.
Antonio
4:48 p.m.
On 21 Jan 2009 at 20:52, arcarlini at iee.org wrote:
If there were enough accidents/injuries etc. then
there would be some
repurcussions for both the manufacturer that sold the wart-driven-device
and also the wart maker.
Sure, the same way that Christmas-tree light strings are "safe".
Were it not for tradition, I cannot imagine that any underwriting or
certifying agency would approve of line current-powered strings of
low-voltage series-connected lamps on lightweight insulated #20 wire
on a tree whose base sits in a stand full of water. No protective
grounding, no GFCI. At least they have fuses in the plugs now.
Older ones didn't.
I suppose they're safer than candles...
Since these light strings are sold in discount stores by fly-by-night
seasonal importers, who are you going to sue?
Cheers,
Chuck
22 Jan
22 Jan
1:50 p.m.
Sure, the same way that Christmas-tree light strings
are "safe".
Were it not for tradition, I cannot imagine that any underwriting or
certifying agency would approve of line current-powered strings of
low-voltage series-connected lamps on lightweight insulated #20 wire
I beleive that Christmas lights are one of the few (if not the only)
single-insulated non-earthed device that can be sold in the UK. Althoguh
a lot of the better-grade light sets sold over here are either
low-voltage bulbs or LEDs effectively in parallel running of a 12V or 24V
wall-wart (for all I hate the latter ,they are safer than the older type
of series-string lights)
I also wonder how the light bulb sockets (both the BC (Baynoet Cap) ones
used in the UK and the ES ones used elsewhere are approved. With the bulb
removed (which can be done without the use of a tool), there are exposed
livel parts. (Yes, I know the better makes of BC holder contain automatic
switches to break the connections when the bulb is removed, but an awful
lot of holders without said switches are around).
-tony
6:13 p.m.
On 22/01/2009 18:50, Tony Duell wrote:
I beleive that Christmas lights are one of the few (if
not the only)
single-insulated non-earthed device that can be sold in the UK.
[ ... ]
I also wonder how the light bulb sockets (both the BC
(Baynoet Cap) ones
used in the UK and the ES ones used elsewhere are approved. With the bulb
removed (which can be done without the use of a tool), there are exposed
livel parts.
The IET Wiring Regulations merely require that you can't touch a live
part with a finger (and there's a standard to define how fat a finger
is) and without the use of a tool. It doesn't mean you can't remove the
bulb without a tool, it means you can't then touch the live part without
a tool. In the case of Christmas lights the metal is somewhat recessed,
and you can't get a finger in, so it's allowed. I assume here that
we're talking about the ones that use miniature E5 (5mm ES) bulbs. Of
course even in this case, you can touch the live part with a
screwdriver, the tines of a table fork, a paperclip, etc -- but those
are defined as tools :-) Amusingly, these lights are classed as if
double-insulated, even though all the ones I've seen are not -- the
rather bizarre justification for that definition seems to be simply that
they have no earth wire!
Can shops still sell such strings of lights? I've not seen any for
ages, only the spare bulbs, and ELV sets. The last time I saw any IET
publication about them was dated 2004 and I'm not sure if they are still
sold.
--
Pete Peter Turnbull
Network Manager
University of York
6:33 p.m.
On Thu, 2009-01-22 at 23:13 +0000, Pete Turnbull wrote:
On 22/01/2009 18:50, Tony Duell wrote:
Normal bayonet cap bulbs like in ordinary household light fittings have
exposed live parts that can be touched with a finger. The bulb base is
about an inch across! You'd have to have hellish fat fingers to not fit
them into the socket.
Look I'll show y{d{tt{gb{34$?{22
NO CARRIER
I beleive that Christmas lights are one of the
few (if not the only)
single-insulated non-earthed device that can be sold in the UK.
[ ... ]
I also wonder how the light bulb sockets (both
the BC (Baynoet Cap) ones
used in the UK and the ES ones used elsewhere are approved. With the bulb
removed (which can be done without the use of a tool), there are exposed
livel parts.
The IET Wiring Regulations merely require that you can't touch a live
part with a finger (and there's a standard to define how fat a finger
is) and without the use of a tool. It doesn't mean you can't remove the
bulb without a tool, it means you can't then touch the live part without
a tool. In the case of Christmas lights the metal is somewhat recessed,
and you can't get a finger in, so it's allowed. 
7:01 p.m.
On 22 Jan 2009 at 23:13, Pete Turnbull wrote:
The IET Wiring Regulations merely require that you
can't touch a live
part with a finger (and there's a standard to define how fat a finger
is) and without the use of a tool. It doesn't mean you can't remove the
bulb without a tool, it means you can't then touch the live part without
a tool. In the case of Christmas lights the metal is somewhat recessed,
and you can't get a finger in, so it's allowed. I assume here that
we're talking about the ones that use miniature E5 (5mm ES) bulbs. Of
course even in this case, you can touch the live part with a
screwdriver, the tines of a table fork, a paperclip, etc -- but those
are defined as tools :-) Amusingly, these lights are classed as if
double-insulated, even though all the ones I've seen are not -- the
rather bizarre justification for that definition seems to be simply that
they have no earth wire!
...or the puppy can chew on it, or baby can see what the pretty bulb
tastes like...
I've never understood why Christmas tree lamps (particularly the
miniature ones) aren't mandated as line-isolated low-voltage devices.
They're still the most prevalent type in the USA.
Cheers,
Chuck
8:53 p.m.
On 22 Jan 2009 at 19:34, William Donzelli wrote:
Never? I suppose it's what you mean by "never":
http://www.hobbycast.net/msds/Patternrelease202.pdf
"In 2002-2005, U.S. fire departments responded to an estimated
average of 210 home structure fires that began with Christmas trees.
These fires caused an average of 24 civilian deaths, 27 civilian
injuries, and $13.3 million in direct property damage per year. "
"Electrical failures or malfunctions were involved in 48% of the home
Christmas tree fires...Decorative lights with line voltage were
involved in 22% of these incidents"
--Chuck
I've never
understood why Christmas tree lamps (particularly the
miniature ones) aren't mandated as line-isolated low-voltage devices.
Probably because they never cause problems.
23 Jan
23 Jan
4:17 p.m.
On 22/01/2009 18:50, Tony Duell wrote:
I have pictures of the 'Standard Test FInger' (a jointeed metal thing)
used to test for this...
I beleive that Christmas lights are one of the
few (if not the only)
single-insulated non-earthed device that can be sold in the UK.
[ ... ]
I also wonder how the light bulb sockets (both
the BC (Baynoet Cap) ones
used in the UK and the ES ones used elsewhere are approved. With the bulb
removed (which can be done without the use of a tool), there are exposed
livel parts.
The IET Wiring Regulations merely require that you can't touch a live
part with a finger (and there's a standard to define how fat a finger
is) and without the use of a tool. It doesn't mean you can't remove the bulb without a tool, it means you can't then touch
the live part without
a tool. In the case of Christmas lights the metal is somewhat recessed,
I was thining of the dull-size BC and ES lampholders used for mains
bulbs (and thus with mains applied to the contacts). You can remove the
bulb without a tool and you can most certainly then touch live parts
with any normal-sized human finger.
and you can't get a finger in, so it's
allowed. I assume here that
we're talking about the ones that use miniature E5 (5mm ES) bulbs. Of
course even in this case, you can touch the live part with a
screwdriver, the tines of a table fork, a paperclip, etc -- but those
are defined as tools :-) Amusingly, these lights are classed as if
double-insulated, even though all the ones I've seen are not -- the
Are they? I understood the normal appliances were 'Class 1' if they had
an earth wire and 'Class 2' if double-insulated. And that 'Class 0' was
single-insulated, but no earth, and about the only class 0 devices that
could still be sold were decorative lights.
-tony
7:22 p.m.
On 23/01/2009 21:17, Tony Duell wrote:
You could be right about that -- I was basing my assessment on the fact
that they're tested using Class II tests and settings (at least on our
Seaward testers).
--
Pete Peter Turnbull
Network Manager
University of York
I was thining of the dull-size BC and ES lampholders
used for mains
bulbs (and thus with mains applied to the contacts). You can remove the
bulb without a tool and you can most certainly then touch live parts
with any normal-sized human finger.
Yes, I realised that after Gordon's comment.
Amusingly,
these lights are classed as if
double-insulated, even though all the ones I've seen are not -- the
Are they? I understood the normal appliances were 'Class 1' if they had
an earth wire and 'Class 2' if double-insulated. And that 'Class 0' was
single-insulated, but no earth, and about the only class 0 devices that
could still be sold were decorative lights. 
21 Jan
21 Jan
5:19 p.m.
On Wed, Jan 21, 2009 at 3:52 PM, <arcarlini at iee.org> wrote:
That said, I _do_ dislike the fact that they are often
glued together
rather than screwed together
Hammer.
... I've certainly rescued devices in the past by
swapping
a cable from a dead wart onto a different but power-compatible one and
that's considerably harder these days!
If you can't get it open, you can still splice the old cable on the
new wart. I'll be pedantic and recommend heat shrink over electrical
tape - it doesn't turn to goo and melt off. Masking tape is *right
out* (but I've seen lots of it covering splices).
I also dislike the fact that all the warts get mixed
up and it takes me
ages to find the one that goes with the $foo I want to work with.
I have a paint marker and routinely mark what device the wart goes
with, and mark the device with a sharpie when the manufacturer hasn't
bothered to mark the outside of the device with what power the wart
supplies.
-ethan
5:43 p.m.
Ethan Dicks wrote:
I prefer using a Dremel with a cut-off wheel.
I tend to shrinkwrap the wall-wart to the device before placing in storage.
Peace... Sridhar
That said, I
_do_ dislike the fact that they are often glued together
rather than screwed together
Hammer. I also dislike
the fact that all the warts get mixed up and it takes me
ages to find the one that goes with the $foo I want to work with.
I have a paint marker and routinely mark what device the wart goes
with, and mark the device with a sharpie when the manufacturer hasn't
bothered to mark the outside of the device with what power the wart
supplies. 
22 Jan
22 Jan
1:50 p.m.
On Wednesday 21 January 2009 05:43:20 pm Sridhar Ayengar wrote:
Ethan Dicks wrote:
I prefer using a Dremel with a cut-off wheel.
Are you guys talking about opening dead ones to recover the load-end cable off
them or opening ones that still work and that will be re-closed at some
point?
I've been thinking about trying MEK applied along the seam with swabs.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
That
said, I _do_ dislike the fact that they are often glued together
rather than screwed together
Hammer.
2:08 p.m.
On 22 Jan 2009 at 13:50, Roy J. Tellason wrote:
I've been thinking about trying MEK applied along
the seam with swabs.
MEK works with some plastics and turns others to mush or has little
effect at all. Methylene chloride seems to be a better choice,
particularly for clear stock. Just repaired a pair of plastic-
handled scissors using it and you can't tell it was ever broken.
Cheers,
Chuck
2:20 p.m.
On Thu, Jan 22, 2009 at 2:08 PM, Chuck Guzis <cclist at sydex.com> wrote:
On 22 Jan 2009 at 13:50, Roy J. Tellason wrote:
Yeah... I was just looking that up, since I wanted some plastic-weld
but don't like paying several dollars per oz at the hobby store... I
guess "proper" liquid polystyrene cement is Methylene Chloride, but
MEK is easy to get at the hardware store by the pint or larger
container.
I have a few things I'd like to "weld" up... guess I'll have to find a
source of Methylene Chloride somewhere. It seems to be the right
stuff for many assembly and repair applications.
I first used "plastic weld" at about age 11 and found it much nicer
for an impatient kid than toluene-based "model cement"... besides
finger prints and sagging bits from overapplication of the thicker
cements, plastic weld was ready to go in seconds so I could spend more
time aligning and assembling than waiting for complex assemblies to
dry before moving on to the next step.
I haven't used it to repair wall warts, but I've always thought it was
the best stuff to use if I ever got as far as regluing.
-ethan
I've been thinking about trying MEK applied
along the seam with swabs.
MEK works with some plastics and turns others to mush or has little
effect at all. Methylene chloride seems to be a better choice,
particularly for clear stock. Just repaired a pair of plastic-
handled scissors using it and you can't tell it was ever broken.
4:39 p.m.
On 22 Jan 2009 at 14:20, Ethan Dicks wrote:
Yeah... I was just looking that up, since I wanted
some plastic-weld
but don't like paying several dollars per oz at the hobby store... I
guess "proper" liquid polystyrene cement is Methylene Chloride, but
MEK is easy to get at the hardware store by the pint or larger
container.
Just the opposite here--MEK can't be found nearby in town, due to the
city toxics reporting laws (too much trouble to stock it, so
merchants don't). I have to drive to the next town to find it.
I have a few things I'd like to "weld"
up... guess I'll have to find a
source of Methylene Chloride somewhere. It seems to be the right
stuff for many assembly and repair applications.
Hobby shops carry the stuff under various names: Plastiweld is one,
Bondene is another. Oddly, the next largest size that's easy to
obtain seems to be a 55 gallon drum...
It's great for styren or ABS. It's also in many paint strippers.
Cheers,
Chuck
6:35 p.m.
On Thu, Jan 22, 2009 at 4:39 PM, Chuck Guzis <cclist at sydex.com> wrote:
Right. I'm trying to find it from a source that doesn't dole it out
in 1oz containers for a few bucks. I don't mind paying a few bucks
per liter, but not per ounce
On 22 Jan 2009 at 14:20, Ethan Dicks wrote:
Hmm... no problem here - the closest DIY shop has it in the paint
section for $7 per large container (1L? 2L? 4L?) but doesn't have
Methylene Chloride in with the other solvents.
I guess "proper" liquid polystyrene
cement is Methylene Chloride, but
MEK is easy to get at the hardware store by the pint or larger
container.
Just the opposite here--MEK can't be found nearby in town, due to the
city toxics reporting laws (too much trouble to stock it, so
merchants don't). I have to drive to the next town to find it. I have a few
things I'd like to "weld" up... guess I'll have to find a
source of Methylene Chloride somewhere...
Hobby shops carry the stuff under various names: Plastiweld is one,
Bondene is another. Oddly, the next largest size that's easy to
obtain seems to be a 55 gallon drum...
That would be, um, a bit much for hobby use.
It's great for styren or ABS. It's also in
many paint strippers.
Yes... I am planning on working with styrene and ABS, so it sounds
perfect. It's good to know that acetone is good with acrylic. That'd
be the other one I'd probably work with.
-ethan
7:18 p.m.
On 22/01/2009 23:35, Ethan Dicks wrote:
It's good to know that acetone is good with
acrylic. That'd
be the other one I'd probably work with.
Actually, it's not, particularly. It attacks acrylic, but isn't very
good for welding it. Chloroform is far superior, but do remember the
ventilation required!
--
Pete Peter Turnbull
Network Manager
University of York
23 Jan
23 Jan
1:07 a.m.
Pete Turnbull wrote:
On 22/01/2009 23:35, Ethan Dicks wrote:
Not if you really want to have a good time.
Peace... Sridhar
It's good to know that acetone is good with
acrylic. That'd
be the other one I'd probably work with.
Actually, it's not, particularly. It attacks acrylic, but isn't very
good for welding it. Chloroform is far superior, but do remember the
ventilation required!
22 Jan
22 Jan
5:56 p.m.
On 22/01/2009 19:20, Ethan Dicks wrote:
MEK is used industrially for ABS and PVC, but not much else (it's used
in the printing industry as an ink remover and rubber restorer,
however). It's great on those, and much cheaper than methylene
chloride, but methylene chloride works on one or two plastics where MEK
doesn't. "clear stock" won't be ABS or PVC as neither can be
transparent; if MEK dissolves it (messily) it's probably polystyrene,
which methylene chloride works moderately well on. If you want to weld
acrylic (Perspex/Lexan/Plexiglass), though, professionals use chloroform.
--
Pete Peter Turnbull
Network Manager
University of York
On Thu, Jan 22, 2009 at 2:08 PM, Chuck Guzis
<cclist at sydex.com> wrote:
> On 22 Jan 2009 at 13:50, Roy J. Tellason wrote:
MEK works with
some plastics and turns others to mush or has little
effect at all. Methylene chloride seems to be a better choice,
particularly for clear stock. Just repaired a pair of plastic-
handled scissors using it and you can't tell it was ever broken.
Yeah... I was just looking that up, since I wanted some plastic-weld
but don't like paying several dollars per oz at the hobby store... I
guess "proper" liquid polystyrene cement is Methylene Chloride, but
MEK is easy to get at the hardware store by the pint or larger
container.
2:41 p.m.
Roy J. Tellason wrote:
I prefer using a Dremel with a cut-off
wheel.
Are you guys talking about opening dead ones to recover the load-end cable off
them or opening ones that still work and that will be re-closed at some
point?
The latter.
That said, I
_do_ dislike the fact that they are often glued together
rather than screwed together
Hammer. I've been thinking about trying MEK applied along
the seam with swabs.
I can verify that it works. You just have to make sure to close the
seam up quickly after applying the MEK *sparingly*, and that the seam is
clamped firmly while the plastic rehardens.
Peace... Sridhar
4:31 p.m.
On Thursday 22 January 2009 02:41:29 pm Sridhar Ayengar wrote:
Roy J. Tellason wrote:
Are you guys talking about opening dead ones to recover the load-end
cable off them or opening ones that still work and that will be re-closed
at some point?
The latter.
Actually I was thinking about using it to *open* these (and similarly sealed
stuff) without resorting to things like hammers, dremel, etc.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
> That said, I _do_ dislike the fact that they are
often glued together
> rather than screwed together
Hammer.
I prefer using a Dremel with a cut-off wheel. I've been thinking about trying MEK applied
along the seam with swabs.
I can verify that it works. You just have to make sure to close the
seam up quickly after applying the MEK *sparingly*, and that the seam is
clamped firmly while the plastic rehardens.
Peace... Sridhar
4:45 p.m.
Roy J. Tellason wrote:
On Thursday 22 January 2009 02:41:29 pm Sridhar
Ayengar wrote:
That sounds like it would be a mess.
Peace... Sridhar
Roy J. Tellason wrote:
The latter.
Actually I was thinking about using it to *open* these (and similarly sealed
stuff) without resorting to things like hammers, dremel, etc. >>
That said, I _do_ dislike the fact that they are often glued together
>> rather than screwed together
> Hammer.
I prefer using a Dremel with a cut-off wheel.
Are you guys talking about opening
dead ones to recover the load-end
cable off them or opening ones that still work and that will be re-closed
at some point? I've been thinking about trying MEK applied
along the seam with swabs.
I can verify that it works. You just have to make sure
to close the
seam up quickly after applying the MEK *sparingly*, and that the seam is
clamped firmly while the plastic rehardens. 
5:07 p.m.
Sridhar Ayengar wrote:
Although perhaps a fitting end. The natural approach could be taken, I suppose
- fill with water and put outside to freeze... :-)
Actually I was
thinking about using it to *open* these (and similarly
sealed stuff) without resorting to things like hammers, dremel, etc.
That sounds like it would be a mess.
5:16 p.m.
On Thu, 2009-01-22 at 16:07 -0600, Jules Richardson wrote:
Sridhar Ayengar wrote:
Although perhaps a fitting end. The natural approach could be taken, I suppose
- fill with water and put outside to freeze... :-)
Hydraulic press. A CD-ROM yields up its secrets...
http://www.youtube.com/watch?v=glRMdVc_6cQ
Gordon
Actually
I was thinking about using it to *open* these (and similarly
sealed stuff) without resorting to things like hammers, dremel, etc.
That sounds like it would be a mess.
5:31 p.m.
On Thursday 22 January 2009 04:45:43 pm Sridhar Ayengar wrote:
Roy J. Tellason wrote:
Maybe I'll try the stuff out on some scrap plastic first, then. I've heard
about it being handy, but haven't used it yet.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
On Thursday 22 January 2009 02:41:29 pm Sridhar
Ayengar wrote:
That sounds like it would be a mess. Roy J. Tellason wrote:
Actually I was thinking about using it to *open* these (and similarly
sealed stuff) without resorting to things like hammers, dremel, etc. >>> That said, I _do_ dislike the fact
that they are often glued
>>> together rather than screwed together
>>
>> Hammer.
>
> I prefer using a Dremel with a cut-off wheel.
Are you guys talking about opening dead ones to recover the load-end
cable off them or opening ones that still work and that will be
re-closed at some point?
The latter.
I've been thinking about trying MEK applied
along the seam with swabs.
I can verify that it works. You just have to make sure to close the
seam up quickly after applying the MEK *sparingly*, and that the seam is
clamped firmly while the plastic rehardens. 
5:39 p.m.
>>>> "Roy" == Roy J Tellason
<rtellason at verizon.net> writes:
Roy> Maybe I'll try the stuff out on some scrap plastic first, then.
Roy> I've heard about it being handy, but haven't used it yet.
You'd have to make sure it's the right kind of plastic. There is a
whole lot of variation as to what solvents (if any) will dissolve
"plastic". PE and PTFE don't dissolve at all, while many other
plastics have their particular "good solvent". I remember furan for
vinyl (as in "waterbed patch kits"), something completely different
for polystyrene, and probably something different yet again for
plexiglas.
Then there are fun details like this one: ethanol is a nice harmless
cleaning fluid for many things, including most plastics. But it will
turn plexiglas matte.
paul
6 p.m.
Polystyrene dissolves easily with acetone. Someone showed me that around 10 years ago,
when we had a quiet day in the lab.
Some new staff occasionally use acetone to try to clean marks off of balance doors (the
sidebits) and often dissolve the plastic runner so that the doors no longer smoothly slide
open/closed, instead they stick :(
Regards,
Andrew B
aliensrcooluk at yahoo.co.uk
PS. Anyone here in the UK see the Royal Institution Lectures on Channel 5 over Christmas?
If you did can you please point me (offlist please) in the direction of a good guide on
how quantum CPU's work. I understood all the other stuff, but the quantum stuff
confused me :(
--- On Thu, 22/1/09, Paul Koning <Paul_Koning at dell.com> wrote:
From: Paul Koning <Paul_Koning at dell.com>
Subject: Re: Wall warts; was: hams on classiccmp
To: cctalk at classiccmp.org
Date: Thursday, 22 January, 2009, 10:39 PM
>>>> "Roy" == Roy J Tellason
<rtellason at verizon.net> writes:
Roy> Maybe I'll try the stuff out on some scrap plastic first, then.
Roy> I've heard about it being handy, but haven't used it yet.
You'd have to make sure it's the right kind of plastic. There is a
whole lot of variation as to what solvents (if any) will dissolve
"plastic". PE and PTFE don't dissolve at all, while many other
plastics have their particular "good solvent". I remember furan for
vinyl (as in "waterbed patch kits"), something completely different
for polystyrene, and probably something different yet again for
plexiglas.
Then there are fun details like this one: ethanol is a nice harmless
cleaning fluid for many things, including most plastics. But it will
turn plexiglas matte.
paul
6:09 p.m.
Andrew Burton wrote:
Polystyrene dissolves easily with acetone. Someone
showed me that
around 10 years ago, when we had a quiet day in the lab. Some new
staff occasionally use acetone to try to clean marks off of balance
doors (the sidebits) and often dissolve the plastic runner so that
the doors no longer smoothly slide open/closed, instead they stick :(
A girl in my lab session proved conclusively that acetone is effective
at dissolving polyester.
Peace... Sridhar
6:15 p.m.
On 22/01/2009 22:39, Paul Koning wrote:
Then there are fun details like this one: ethanol is a
nice harmless
cleaning fluid for many things, including most plastics. But it will
turn plexiglas matte.
And never use IPA to clean the focus screen in your SLR camera. I had
to have a Pentax dismantled and the screen replaced after that one.
--
Pete Peter Turnbull
Network Manager
University of York
6:23 p.m.
Pete Turnbull wrote:
I would go further. I would say, never use anything stronger than water
to clean any flat-panel display.
Peace... Sridhar
Then there are
fun details like this one: ethanol is a nice harmless
cleaning fluid for many things, including most plastics. But it will
turn plexiglas matte.
And never use IPA to clean the focus screen in your SLR camera. I had
to have a Pentax dismantled and the screen replaced after that one.
6:38 p.m.
On 22/01/2009 23:23, Sridhar Ayengar wrote:
Pete Turnbull wrote:
I would go further. I would say, never use anything stronger than water
to clean any flat-panel display.
Glass ones are OK. But the focussing screen in an SLR (even a DSLR,
which is not what I was talking about) is not a flat-panel display :-)
It's an optical device, not an electronic one -- it's all done with
mirrors (and pentaprisms) :-)
--
Pete Peter Turnbull
Network Manager
University of York
Then
there are fun details like this one: ethanol is a nice harmless
cleaning fluid for many things, including most plastics. But it will
turn plexiglas matte.
And never use IPA to clean the focus screen in your SLR camera. I had
to have a Pentax dismantled and the screen replaced after that one.
23 Jan
23 Jan
4:20 p.m.
On 22/01/2009 22:39, Paul Koning wrote:
Thad depends on what the focussing screen is made of. Some of my cameras
are old enough to have real ground-glass screens, which are not attacked
by any common cleaning solvents. But the plastic ones used in more recent
cameras are very easy to damage. Having just looked at a Spotmatic, I can
confirm the focussing screen in that is plastic, and that it comes out
upwards arter removing the top plate and pentaprism, so it's not trivial
to replace.
-tony
Then there are fun details like this one: ethanol
is a nice harmless
cleaning fluid for many things, including most plastics. But it will
turn plexiglas matte.
And never use IPA to clean the focus screen in your SLR camera. I had
to have a Pentax dismantled and the screen replaced after that one.
7:10 p.m.
On 23/01/2009 21:20, Tony Duell wrote:
The one I damaged wasn't a Spotmatic (though I do have one), it was my
trusty ME Super. The screen comes out the top much as a Spotmatic one
does, so I wasn't pleased with myself. In case you're wondering why the
solvent was there at all, it was a problem that many classiccmpers will
be familiar with: aged foam that had crumbled and gone gooey. It's used
for the light seals around the camera back and mirror box, and some from
the mirror box had found its way onto the screen.
--
Pete Peter Turnbull
Network Manager
University of York
And never use
IPA to clean the focus screen in your SLR camera. I had
to have a Pentax dismantled and the screen replaced after that one.
Thad depends on what the focussing screen is made of. Some of my cameras
are old enough to have real ground-glass screens, which are not attacked
by any common cleaning solvents. But the plastic ones used in more recent
cameras are very easy to damage. Having just looked at a Spotmatic, I can
confirm the focussing screen in that is plastic, and that it comes out
upwards arter removing the top plate and pentaprism, so it's not trivial
to replace.
3:29 p.m.
Then there are fun details like this one: ethanol is a
nice harmless
cleaning fluid for many things, including most plastics. But it will
turn plexiglas matte.
I remember some HP displays [1] where the data sheet warned you not to
clean them with 'alcohol' (whether it meant ethanol, or any alcohol I
don't know, and given the prices of the displays I was not going to try
it!). Apparently alcohol would attack the plastic package and cloud up
the viewing lenses.
[1] These were 4 character, 14 segment LED 'starbust' displays with a
built-in character generator ROM and scanner. You had 2 address lines and
some data lines, and you sent it ASCII codes. The numnber '1414' springs
to mind for the smallest/simplest one. I think some other company
(Siemens?) made compatile LED dot matrix displays at one point too.
-tony
5:03 p.m.
On Jan 23, 2009, at 3:29 PM, Tony Duell wrote:
HPDL-1414, I've used a few in projects here. They're damn nice
displays. The datasheet mentions nothing about alcohol, though.
-Dave
--
Dave McGuire
Port Charlotte, FL
Then there are
fun details like this one: ethanol is a nice harmless
cleaning fluid for many things, including most plastics. But it will
turn plexiglas matte.
I remember some HP displays [1] where the data sheet warned you not to
clean them with 'alcohol' (whether it meant ethanol, or any alcohol I
don't know, and given the prices of the displays I was not going to
try
it!). Apparently alcohol would attack the plastic package and cloud up
the viewing lenses.
[1] These were 4 character, 14 segment LED 'starbust' displays with a
built-in character generator ROM and scanner. You had 2 address
lines and
some data lines, and you sent it ASCII codes. The numnber '1414'
springs
to mind for the smallest/simplest one. I think some other company
(Siemens?) made compatile LED dot matrix displays at one point too.
24 Jan
24 Jan
1:45 p.m.
[Alcohol damaging plastics]
HPDL-1414, I've used a few in projects here.
They're damn nice
displays. The datasheet mentions nothing about alcohol, though.
Hmmm.. I was pretty sure it was those displays where the data sheet
specifically mentioned not cleaning them with alcohol, but I could well
be mistaken.
I was using these over 25 years ago, and there are 2 other posibilities.
Firstly, they may have changed the plastic over the years so the more
recent ones are not attacked by alcohol (that might also apply to dot
matrix versions, etc). The other is that I got my displays from RS
components in the UK, and they produced their own data sheet for the ones
they sold (I think just the 1414 and 2416), and it may have contained the
warning about alcohol. I still have that data sheet _somehwere_ , if I
come across it I'll check.
-tony
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