gluing electric blanket wiring for DIY blanket?...

R

Runner

Guest
After being fed up with commercial electric blankets not lasting more
than a few months, I am building my own. It will use 20 feet of Teflon
coated wire with a total output of 40 watts from a 12 VDC source. I am
running into a problem with how to attach the wire. I\'m just going to
use my old, non-functional fleece electric blanket. The thought was to
just glue the wire across the blanket in a zig zag pattern. However,
I\'m not sure what glue would be suitable as I am worried about possible
melting. A few years ago, I made some nylon fabric traps and glued
them together with hot glue. They\'ve been in the sun many times and the
glue has held. Would I be able to use high temp hot glue to glue the
Teflon wire to the blanket? Note that I can\'t sew so that is out of the
question for me.
 
On Thu, 29 Oct 2020 22:03:30 -0400, Runner <runners@aolnospam.com>
wrote:

After being fed up with commercial electric blankets not lasting more
than a few months, I am building my own. It will use 20 feet of Teflon
coated wire with a total output of 40 watts from a 12 VDC source. I am
running into a problem with how to attach the wire. I\'m just going to
use my old, non-functional fleece electric blanket. The thought was to
just glue the wire across the blanket in a zig zag pattern. However,
I\'m not sure what glue would be suitable as I am worried about possible
melting. A few years ago, I made some nylon fabric traps and glued
them together with hot glue. They\'ve been in the sun many times and the
glue has held. Would I be able to use high temp hot glue to glue the
Teflon wire to the blanket? Note that I can\'t sew so that is out of the
question for me.

Try it on a little piece.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
In article <rnfs9j$d5i$1@dont-email.me>, runners@aolnospam.com says...
After being fed up with commercial electric blankets not lasting more
than a few months, I am building my own. It will use 20 feet of Teflon
coated wire with a total output of 40 watts from a 12 VDC source. I am
running into a problem with how to attach the wire. I\'m just going to
use my old, non-functional fleece electric blanket. The thought was to
just glue the wire across the blanket in a zig zag pattern. However,
I\'m not sure what glue would be suitable as I am worried about possible
melting. A few years ago, I made some nylon fabric traps and glued
them together with hot glue. They\'ve been in the sun many times and the
glue has held. Would I be able to use high temp hot glue to glue the
Teflon wire to the blanket? Note that I can\'t sew so that is out of the
question for me.

What you mean: you \"can\'t sew\"? How difficult can it be? Are you aiming
to produce something decorative?
 
In article <rnfs9j$d5i$1@dont-email.me>, runners@aolnospam.com says...
After being fed up with commercial electric blankets not lasting more
than a few months, I am building my own. It will use 20 feet of Teflon
coated wire with a total output of 40 watts from a 12 VDC source. I am
running into a problem with how to attach the wire. I\'m just going to
use my old, non-functional fleece electric blanket. The thought was to
just glue the wire across the blanket in a zig zag pattern. However,
I\'m not sure what glue would be suitable as I am worried about possible
melting. A few years ago, I made some nylon fabric traps and glued
them together with hot glue. They\'ve been in the sun many times and the
glue has held. Would I be able to use high temp hot glue to glue the
Teflon wire to the blanket? Note that I can\'t sew so that is out of the
question for me.

Alternative: buy some iron-on tape and glue it around the cable without
trying to attach to the cable itself. So the cable is in a pocket. The
cable will not get so hot that it opens up the pocket; if it does that
the whole project is too dangerous!
 
On 10/29/2020 10:03 PM, Runner wrote:
... It will use 20 feet of Teflon
coated wire with a total output of 40 watts from a 12 VDC source.  ...

Let\'s not get ahead of ourselves. 8 minutes before posting this you
asked (on S.E.R) how to get the resistance of your wire. Without the
resistance, you must be assuming that the 40w will come from a 3.3A, 12v
power supply. But with very low resistance (as your wire almost
certainly is*), you\'ll get your 3.3A, but at a much reduced voltage
(assuming that the PS doesn\'t shut down on over current). Then you\'ll
have much less than 40W & you\'ll be cold <G>.

To get the 40w from your 3.3A (assumed), 12v supply, your wire\'s total
resistance would have to be 12/3.3 = 3.6R. Once you know the resistance
per foot of your wire, you can figure how long it will have to be. For
copper wire of reasonable size, that could be 100\'s of feet.

* - electric blanket wire is different than regular wire - it\'s
resistance (per foot) is much higher. I salvaged some wire from an old
blanket and its resistance was/is an ohm per foot. 50 times greater
than 22ga copper wire at .02 ohms per foot.
 
On 10/30/20 8:46 AM, Bob Engelhardt wrote:
On 10/29/2020 10:03 PM, Runner wrote:
...  It will use 20 feet of Teflon
coated wire with a total output of 40 watts from a 12 VDC source.  ...

Let\'s not get ahead of ourselves.  8 minutes before posting this you
asked (on S.E.R) how to get the resistance of your wire.  Without the
resistance, you must be assuming that the 40w will come from a 3.3A, 12v
power supply.  But with very low resistance (as your wire almost
certainly is*), you\'ll get your 3.3A, but at a much reduced voltage
(assuming that the PS doesn\'t shut down on over current).  Then you\'ll
have much less than 40W & you\'ll be cold <G>.

To get the 40w from your 3.3A (assumed), 12v supply, your wire\'s total
resistance would have to be 12/3.3 = 3.6R.  Once you know the resistance
per foot of your wire, you can figure how long it will have to be.  For
copper wire of reasonable size, that could be 100\'s of feet.

* - electric blanket wire is different than regular wire - it\'s
resistance (per foot) is much higher.  I salvaged some wire from an old
blanket and its resistance was/is an ohm per foot.  50 times greater
than 22ga copper wire at .02 ohms per foot.

I figured it out and I\'m laying under it now. I didn\'t like the amount
of power that was being generated at 12 V (84 watts), so I went with 5 V
and did a quick and dirty method of checking amps as wire length was
reduced. It turned out that 20 feet of the wire uses 11 amps at 5 V.
So, I took the 20 feet and glued it in a zig zag pattern on the blanket
with the hot glue. After two hours of continuous use, absolutely no
melting of the hot glue so far and the connections are cool. The
warmest part outside of the blanket is actually the wire leading to the
power supply. I borrowed the original wire that was with the Sunbeam
blanket, but its gauge seems to be thin. If it gets too warm, I\'ll have
to upgrade the power wire to something thicker.

I guess one good thing here is that I will need an additional blanket or
two covering the electric blanket once the house gets colder. It\'s 63 F
in here now and I have a dollar store fleece blanket on top and I\'m comfy.

I did notice something during my experiments. I at first applied 12 V
through the entire wire length (I think it\'s 60 feet or so but not
certain). At 12 V, there was 7 A used. Although wattage was more, the
wire seemed cooler than it is now at 55 W @ 20 feet. My guess is
because less wire means more power per foot even with less wattage than
there was at 84 W.

If I would have had a cheap way to control output, I would have gone
with the 84 watt version. All I had on hand was a PWM dimmer used for
dimming LED light arrays. Although rated for 12 V @ 8 A, it burned up
almost instantly. I wasn\'t surprised, but not sure what I would have
used to vary output.
 
In sci.electronics.design, Runner <runners@aolnospam.com> wrote:
After being fed up with commercial electric blankets not lasting more
than a few months, I am building my own.

I have vivid memories of an electric blanket starting a fire in my
parent\'s bedroom when I was a kid. How confident are you that you can
can be more fire-safe than an commercially produced one?

Would I be able to use high temp hot glue to glue the Teflon wire to
the blanket?

Even if it doesn\'t melt in use, I don\'t think hot melt glue will hold up
well to repeated movement.

> Note that I can\'t sew so that is out of the question for me.

Sewing is not hard. Easier than sewing? Fill a hot water bottle from the
kettle and put it in the bed every night.

Elijah
------
selected an extra large kettle for the hot water bottle needs
 
On Thu, 29 Oct 2020 22:03:30 -0400, Runner <runners@aolnospam.com>
wrote:

After being fed up with commercial electric blankets not lasting more
than a few months, I am building my own. It will use 20 feet of Teflon
coated wire with a total output of 40 watts from a 12 VDC source. I am
running into a problem with how to attach the wire. I\'m just going to
use my old, non-functional fleece electric blanket. The thought was to
just glue the wire across the blanket in a zig zag pattern. However,
I\'m not sure what glue would be suitable as I am worried about possible
melting. A few years ago, I made some nylon fabric traps and glued
them together with hot glue. They\'ve been in the sun many times and the
glue has held. Would I be able to use high temp hot glue to glue the
Teflon wire to the blanket? Note that I can\'t sew so that is out of the
question for me.

You won\'t be gluing teflon wires with hot-melt glue - the glue won\'t
stick.

Teflon melts at something like 500 F, and teflon-based fabric used for
radomes and enclosed tennis courts are bonded using a lower-melting
kind of teflon as a \"brazing\" alloy.

Joe Gwinn
 
On 10/30/20 4:07 PM, Eli the Bearded wrote:
In sci.electronics.design, Runner <runners@aolnospam.com> wrote:
After being fed up with commercial electric blankets not lasting more
than a few months, I am building my own.

I have vivid memories of an electric blanket starting a fire in my
parent\'s bedroom when I was a kid. How confident are you that you can
can be more fire-safe than an commercially produced one?

Well, as I said in the other group, if a commercial brand can be shown
to last more than part of one season, I would buy it. I\'ve tried
Sunbeam and Biddleford. Neither last more than part of a season. I
returned three Sunbeams three years ago and finally used their heated
throw, which has lasted since then although the heating has dropped
dramatically. Commercial brands today are junk. I grew up with a
Sunbeam heated blanket that lasted from preteen to college years. I
seriously regret throwing that away.

There are troubleshooting threads elsewhere on the Sunbeams as the
problem seems to stem from a circuit board located inside the blanket\'s
plug in socket. There are apparently sensors there that no longer allow
heating after a short period of time. I checked the board myself and it
consists of a couple of surface mount resistors, caps and a transistor.


Would I be able to use high temp hot glue to glue the Teflon wire to
the blanket?

Even if it doesn\'t melt in use, I don\'t think hot melt glue will hold up
well to repeated movement.

Probably not which is why I have iron on no sewing fabric on the way.
The wire will be pocketed within it over its full length.

Note that I can\'t sew so that is out of the question for me.

Sewing is not hard. Easier than sewing? Fill a hot water bottle from the
kettle and put it in the bed every night.

Limited income means that I don\'t run heat at night and only enough
during daytime to keep the pipes from freezing. Daytime temps in the
main part of the house will soon average 47-55 F until early March. A
hot water bottle isn\'t going to cut it. This has been going on for
four years. Up until now, I\'ve worn multilayered thick clothing outside
of the bed during the daytime and run the heated throw at night. As I
said, the throw has lost its heating capacity too, so there are two
blankets on top of it, plus I wear extra clothing. Just tired of living
this way. Trying to cut back on wearing all the clothing/ blankets to
bed at night. Maybe devise an electric heated jacket for daytime use
too with some of the carbon fiber material (which I currently don\'t have).


Elijah
------
selected an extra large kettle for the hot water bottle needs
 
In article <1otopfdpofjg2pgbrmdg04h8k5hbfnrlei@4ax.com>,
Joe Gwinn <joegwinn@comcast.net> wrote:
You won\'t be gluing teflon wires with hot-melt glue - the glue won\'t
stick.

You won\'t *glue* the wire, as such, more embed it in a blob of
plastic -- as long as hot-melt goes under AND over the wire :)
--
--------------------------------------+------------------------------------
Mike Brown: mjb[-at-]signal11.org.uk | http://www.signal11.org.uk
 
On 10/30/2020 3:07 PM, Eli the Bearded wrote:
In sci.electronics.design, Runner <runners@aolnospam.com> wrote:
After being fed up with commercial electric blankets not lasting more
than a few months, I am building my own.
I have vivid memories of an electric blanket starting a fire in my
parent\'s bedroom when I was a kid. How confident are you that you can
can be more fire-safe than an commercially produced one?

Would I be able to use high temp hot glue to glue the Teflon wire to
the blanket?
Even if it doesn\'t melt in use, I don\'t think hot melt glue will hold up
well to repeated movement.
Reminds of a couple that visited Fl from Indiana. They bought some
string light that had sea shells on each light.

They hung the lights on their dock back home, They were sitting out on
the dock one day and slowly the the shells

started dropping. The hot glue was softening and and the weight of the
shells caused them to drop one by one.

Mikek



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