How to shrink heat shrink tubing?

[Michael A. Terrell]

larry moe 'n curly wrote:

Michael A. Terrell wrote:

larry moe 'n curly wrote:

http://www.harborfreight.com/1500-watt-dual-temperature-heat-gun-572-1112-96289.html
$19.99 regular price. On sale for $9.99 at times.

I received their weekly e-mail right after I posted. It is on sale
for $7.99 with the coupon below:

http://www.harborfreightusa.com/html/wkend0517/images/2.jpg

Here is the user manual:

http://images.harborfreight.com/manuals/96000-96999/96289.pdf

The diode in series with the heating element is a 1N5408, rated
for 3 amps average. The heater draws 8A average on low.

So my question is, how long will this 3A diode last?

That 3 A rating is for continuous duty at
a high operating temperature, not intermittent. The peak current rating
is 200A. The case would likely melt before the diode would fail.

Doesn't the continuous amp rating for a diode apply for any load
lasting more than something like one 60 Hz cycle (or half-cycle?). I
normally run a heat gun a lot longer than that, maybe up to 2
minutes at a time.

Have you used it for that two minutes? That should answer your
question, and show that it takes more than two minutes to damage it.

It takes time to heat the junction in the diode. The heat is
produced only when forward biased, and is from the forward voltage drop,
times the current flow. The higher the current, the faster it heats.
Since a heat gun usually gets very intermittent duty in low heat mode,
it works.

If it can handle a couple 200 amp half cycles while charging an
electrolytic in a piece of electronic equipment, it can handle the extra
current for the heating element even though it is above the 3A
continuous rating.

It looks like the motor is run from a tap on the heating element.
There is no schematic in the manual. I only saw the one diode, across
the switch in mine. Also, how often will you use one on low heat? I
rarely do, usually only when I accidentally hit the wrong end of the
rocker switch.

BTW, if that diode fails, all it will do is make it run at full heat
in either 'ON' position.

I'll bet customers will either not notice that the gun always puts out
full power (diode shorts), or they won't care that it doesn't work at
low heat (diode opens). I checked a few different items, including
some cheapo PC power supplies, and couldn't find any where the diodes
were underrated so much

The usual failure mode would be shorted, unless the internal
connection fractured and separated.

I bought this heat gun to desolder surface mount stuff, and it seems
that its low setting puts out temperatures closer to what hot air
soldering equipment does.

I prefer full heat for that job. I just keep it a little further
away from the board. I see less damage to boards that way. I used to
have a 6" solder pot that I would float a scrap board on, then use a
pair of pliers on the corner to smack it against something to eject all
the molten solder. I recycled thousands of 256 kb memory ICs back in
the '80s at $2.75 each. There was a huge shortage of new ICs, so they
sold as fast as I could pull them and re-tin the leads.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

 

[Michael A. Terrell]

Mark Allread wrote:

Michael A. Terrell wrote:

Mark Allread wrote:

And there you have it. I work with cabling in a TV station, requiring no
more than a dozen pieces done at any given time, and you work with small
wiring inside a chassis on an assembly line, doing hundreds. Each
function has its own equipment needs.

But a butane lighter - especially the "jet" types that behave like tiny
brazing torches - will flame downward well enough, unless they're built
to draw fuel only while upright.

I removed the "Hot air" tip from a butane soldering iron once, and found
it even faster than the lighter, but it required more care in use. If
one tipped it the wrong way, the flame would flare due to it drawing
liquid instead of gas butane.


I used a lot of clear heatshrink to label cables for TV stations and
CATV headends. I preferred to label it before it was inside a rack,
whenever possible.


Indeed - whenever possible. That's how I put in the replacement
Production switcher, after all.

When the cable is to be run through the length of the building, through
tight support brackets already crammed with cable, it is sometimes best
to run one cable at a time and then label each when finished. Heh, time
for a little walk down memory lane...

Ah, the weeks I spent pulling obsolete cable out of that installation,
trying to make room for new cable... Whoever had worked there before me
had left quite a lot of work undocumented... There are few greater sins.

Try a military Radio & TV station (AFRTS) where nothing was
documented. After 20& years of equipment being moved around or replaced,
it was a nightmare. I had the master monitor fail one night, but
couldn't disconnect it, because the main transmitter was at the end of
that loop. They had a nice set of Grass Valley video DAs, but only used
one of the four outputs on each. Add to that, some video connectors
were BNC, and others were PL-259 since the station was built during the
time manufacturers used both.

I got fed up with intermittent cables, so one Saturday I ran a
temporary cable from the film chain strait to the transmitter and
started pulling out dead cables. The 12" * 18" cable tray was full when
I started. When I finished, the bundle was under 6" and several
thousand feet of dead cable were laying in the corner of the transmitter
& control room. That master monitor had seven pieces of coax between it
and the video switcher. There was over 100 abandoned cables I pulled
out. Most had one bad connector, and some had both bad. The other
engineer walked in and almost fainted, but I had everything in place in
time for or noon newscast, and finished everything else before my 20
hour shift ended.


They had the audio board fail in the TV control room at one time, so
they extended all the lines to the radio station's audio console and
used the preview output to feed the TV transmitter. When they got the
board back from the AFRTS service depot, they left the extra wire
connected. You could see radio station's the AM modulation in the video
baseband, from the ground loop that mess caused.

My Chief Engineer cracked up when I mentioned that "there is something
fundamentally wrong with any job that requires knee pads and a
squeeze-bottle of (cable) lube."

Just be glad it was run above the ceiling, under a metal roof. It
was rarely comfortable up there, It was either below zero, or in the 90+
degree range.

Still, by the time I was finished, the digital stuff was in and the
analog stuff (at least that which we no longer needed) was out. I even
built a set of shelves in the basement to hold the obsolete analog
equipment we hadn't sold or scrapped yet, and I carried the stuff down
and filled those shelves.

Digital? We were B&W, and the only ICs were RTL.
(Resistor-Transistor-Logic) ;-)

It was an interesting two years at that station, and then they laid off
more than half the staff, myself included. Ah, such is life.

Those cables were installed well, labeled well, and documented well.
And a lot of equipment that wasn't working, was, by the time I was done.

I built a mobile production van for WACX in the late '80s. I used
about 50 feet of clear heat shrink.

And now I'm a college student on the Dislocated Worker plan.

I imagine I'm in good company here.

Not me. The VA has decided that I'll never work again, and it drives
me crazy.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

 

[Mark Allread]

Michael A. Terrell wrote:

Mark Allread wrote:

Michael A. Terrell wrote:

Mark Allread wrote:

And there you have it. I work with cabling in a TV station, requiring no
more than a dozen pieces done at any given time, and you work with small
wiring inside a chassis on an assembly line, doing hundreds. Each
function has its own equipment needs.

But a butane lighter - especially the "jet" types that behave like tiny
brazing torches - will flame downward well enough, unless they're built
to draw fuel only while upright.

I removed the "Hot air" tip from a butane soldering iron once, and found
it even faster than the lighter, but it required more care in use. If
one tipped it the wrong way, the flame would flare due to it drawing
liquid instead of gas butane.


I used a lot of clear heatshrink to label cables for TV stations and
CATV headends. I preferred to label it before it was inside a rack,
whenever possible.


Indeed - whenever possible. That's how I put in the replacement
Production switcher, after all.

When the cable is to be run through the length of the building, through
tight support brackets already crammed with cable, it is sometimes best
to run one cable at a time and then label each when finished. Heh, time
for a little walk down memory lane...

Ah, the weeks I spent pulling obsolete cable out of that installation,
trying to make room for new cable... Whoever had worked there before me
had left quite a lot of work undocumented... There are few greater sins.


Try a military Radio& TV station (AFRTS) where nothing was
documented. After 20& years of equipment being moved around or replaced,
it was a nightmare. I had the master monitor fail one night, but
couldn't disconnect it, because the main transmitter was at the end of
that loop. They had a nice set of Grass Valley video DAs, but only used
one of the four outputs on each. Add to that, some video connectors
were BNC, and others were PL-259 since the station was built during the
time manufacturers used both.

I got fed up with intermittent cables, so one Saturday I ran a
temporary cable from the film chain strait to the transmitter and
started pulling out dead cables. The 12" * 18" cable tray was full when
I started. When I finished, the bundle was under 6" and several
thousand feet of dead cable were laying in the corner of the transmitter
& control room. That master monitor had seven pieces of coax between it
and the video switcher. There was over 100 abandoned cables I pulled
out. Most had one bad connector, and some had both bad. The other
engineer walked in and almost fainted, but I had everything in place in
time for or noon newscast, and finished everything else before my 20
hour shift ended.


They had the audio board fail in the TV control room at one time, so
they extended all the lines to the radio station's audio console and
used the preview output to feed the TV transmitter. When they got the
board back from the AFRTS service depot, they left the extra wire
connected. You could see radio station's the AM modulation in the video
baseband, from the ground loop that mess caused.


My Chief Engineer cracked up when I mentioned that "there is something
fundamentally wrong with any job that requires knee pads and a
squeeze-bottle of (cable) lube."


Just be glad it was run above the ceiling, under a metal roof. It
was rarely comfortable up there, It was either below zero, or in the 90+
degree range.



Still, by the time I was finished, the digital stuff was in and the
analog stuff (at least that which we no longer needed) was out. I even
built a set of shelves in the basement to hold the obsolete analog
equipment we hadn't sold or scrapped yet, and I carried the stuff down
and filled those shelves.


Digital? We were B&W, and the only ICs were RTL.
(Resistor-Transistor-Logic) ;-)


It was an interesting two years at that station, and then they laid off
more than half the staff, myself included. Ah, such is life.

Those cables were installed well, labeled well, and documented well.
And a lot of equipment that wasn't working, was, by the time I was done.


I built a mobile production van for WACX in the late '80s. I used
about 50 feet of clear heat shrink.


And now I'm a college student on the Dislocated Worker plan.

I imagine I'm in good company here.


Not me. The VA has decided that I'll never work again, and it drives
me crazy.


That all sounds kinda familiar, somehow...

And yeah, those PL-259 video connectors kept unscrewing themselves.
First place to look, for a bad ground connection, especially if somebody
had screwed a BNC adapter onto it. I've been in this line of work for
about 30 years, so I've seen a few of those. Sometimes you'd see
adapters on adapters. I called that a "Stack-o-dapters".

Well, this thread is getting a little long and off-topic. I'll sign off
here.

 

[PeterD]

On Sat, 15 May 2010 16:44:42 -0400, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

I prefer full heat for that job. I just keep it a little further
away from the board. I see less damage to boards that way. I used to
have a 6" solder pot that I would float a scrap board on, then use a
pair of pliers on the corner to smack it against something to eject all
the molten solder. I recycled thousands of 256 kb memory ICs back in
the '80s at $2.75 each. There was a huge shortage of new ICs, so they
sold as fast as I could pull them and re-tin the leads.

Well, the other day I got a new heat gun... Tried it out today, had
this nice dial on the end to set your heat, everything looked nice.

Plugged it in, turned it on, and dialed the heat up and "POP" was what
I heard! oops.

Testing showed me that it was putting out about enough heat to warm my
hand if I held it about four inches from the outlet!

Crap, I hate fixing new stuff, but took it apart, and the SCR in the
dial mechanism had a bad solder joint. New... Of course, chinese crap
made, and I did fix it.

 

[Dave Plowman (News)]

In article <nbu0v5h0h9mdo55meocdgfe43vbobinhu6@4ax.com>,
PeterD <peter2@hipson.net> wrote:

Crap, I hate fixing new stuff, but took it apart, and the SCR in the
dial mechanism had a bad solder joint. New... Of course, chinese crap
made, and I did fix it.

I make a point of never buying crap tools - it simply isn't worth it. Got
quite a few Chinese made which are very good - and incredible value.

If I did buy one which didn't work I'd take it back for a refund or
exchange.

--
*Do infants enjoy infancy as much as adults enjoy adultery?

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[Michael A. Terrell]

PeterD wrote:

On Sat, 15 May 2010 16:44:42 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:


I prefer full heat for that job. I just keep it a little further
away from the board. I see less damage to boards that way. I used to
have a 6" solder pot that I would float a scrap board on, then use a
pair of pliers on the corner to smack it against something to eject all
the molten solder. I recycled thousands of 256 kb memory ICs back in
the '80s at $2.75 each. There was a huge shortage of new ICs, so they
sold as fast as I could pull them and re-tin the leads.

Well, the other day I got a new heat gun... Tried it out today, had
this nice dial on the end to set your heat, everything looked nice.

Plugged it in, turned it on, and dialed the heat up and "POP" was what
I heard! oops.

Testing showed me that it was putting out about enough heat to warm my
hand if I held it about four inches from the outlet!

Crap, I hate fixing new stuff, but took it apart, and the SCR in the
dial mechanism had a bad solder joint. New... Of course, chinese crap
made, and I did fix it.

Good for you!

 

[PeterD]

On Mon, 17 May 2010 00:28:47 +0100, "Dave Plowman (News)"
<dave@davenoise.co.uk> wrote:

In article <nbu0v5h0h9mdo55meocdgfe43vbobinhu6@4ax.com>,
PeterD <peter2@hipson.net> wrote:
Crap, I hate fixing new stuff, but took it apart, and the SCR in the
dial mechanism had a bad solder joint. New... Of course, chinese crap
made, and I did fix it.

I make a point of never buying crap tools - it simply isn't worth it. Got
quite a few Chinese made which are very good - and incredible value.

If I did buy one which didn't work I'd take it back for a refund or
exchange.

Agreed, but it was something I picked up from a store that was going
out of business... It sat in the box for a while, and I decided to try
it yesterday.

 

[David]

In article <8h5ku595n5519poblj8a724md77gbhtnbl@4ax.com>,
mm <NOPSAMmm2005@bigfoot.com> wrote:

On Mon, 10 May 2010 16:24:04 +0000 (UTC), "Geoffrey S. Mendelson"
gsm@cable.mendelson.com> wrote:

I've recently started doing electronic repairs (mostly wiring) and need to
shrink heat shrink tubing. A long time ago I bought a heat gun used for
removing paint and used that. It was 120 volt, so I left it when I moved
here.


A cheap and easy way is to buy a hair dryer from one of the thrift shops

- probably cost you a $1 or so, and does the job.

David

 

[David]

In article <hsepor0qk1@enews6.newsguy.com>,
mzenier@eskimo.com (Mark Zenier) wrote:

In article <slrnhugcn1.e0e.gsm@cable.mendelson.com>,
Geoffrey S. Mendelson <gsm@mendelson.com> wrote:
I've recently started doing electronic repairs (mostly wiring) and need to
shrink heat shrink tubing. A long time ago I bought a heat gun used for
removing paint and used that. It was 120 volt, so I left it when I moved
here.

I've never had much luck (or is it patience?) shrinking it by holding it over
a soldering iron tip. Using a flame, like a cigarette or stove lighter
ends up with burnt plastic.

Is there such a thing as a small heat shrink tube shrinker that does not
toast the things around it? The largest thing I need to shrink over is
about 1/2 an inch most of them are small (20awg or less) wires.

For cable assemblies, I've found that nothing beats a Sunbeam toaster.
Turns itself off, too. You don't have to put it down into the slot,
just hold it over the top.

The trick with lighters is to keep the shrink about 1 1/2 to 2 inches
above the top of the flame.


Mark Zenier mzenier@eskimo.com
Googleproofaddress(account:mzenier provider:eskimo domain:com)

I haven't tried it, but I reckon you could get an old pair of pliers -
heat em up on the stove then gently grip the heat shrink with the hot
jaws - might be worth a try

David

 

[Dave Platt]

Is there such a thing as a small heat shrink tube shrinker that does not
toast the things around it? The largest thing I need to shrink over is
about 1/2 an inch most of them are small (20awg or less) wires.

You can buy small butane-powered torches, with a variety of tips. The
one I bought has a flame tip, a catalytic-heater soldering tip, and a
catalytic-heater hot-air jet. The latter works very well for doing
small heat-shrinking jobs - with the torch turned down to minimum gas
flow it produces a rather delicate and controllable jet of hot air
which can heat the tubing without roasting things nearby.

--
Dave Platt <dplatt@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!