Amazing resistors

[Robert Bruninga]

We have been running a 0.25 Watt small resistor at 3.5 Watts ALL DAY and
it still wont burn out!

We were using it as a "burn resistor" to release a fishing line mechanism.
It does that in 2 seconds. But now 10 hours later it is still going and
wont burn out! (We had hoped it would eventually open so that we could
use the same control line for something else after the resistor opened up.
But it wont.

This is amazing to me. We know that an old composition resistor will burn
smoke and crack in only a few seconds at these power levels, but not the
carbon film at 14 times overload!

Here is the scenario: 7.5v across a 15 ohm 0.25W carbon film resistor.
. It burns the fishing line in 2 seconds
. It begins to smoke at 5
. It smokes for a minute or so
. Then, is black, but no further visible changes
. After an hour it has changed resistance to 20 ohms
. After 5 hours it is up to 29 ohms
. After 10 hours it is up to 35 ohms
. Of course the V^2/R power is going down, but it wont burn out!

Just thought you might find this data point useful!

Bob, WB4APR

[Scott Miller]

I did this several years ago with 200 lb test Spectra line and found I
could push metal film resistors even further. It'd melt the solder off
before the resistor would burn out.

Scott
N1VG

Post by Robert Bruninga
We have been running a 0.25 Watt small resistor at 3.5 Watts ALL DAY and
it still wont burn out!
We were using it as a "burn resistor" to release a fishing line mechanism.
It does that in 2 seconds. But now 10 hours later it is still going and
wont burn out! (We had hoped it would eventually open so that we could
use the same control line for something else after the resistor opened up.
But it wont.
This is amazing to me. We know that an old composition resistor will burn
smoke and crack in only a few seconds at these power levels, but not the
carbon film at 14 times overload!
Here is the scenario: 7.5v across a 15 ohm 0.25W carbon film resistor.
. It burns the fishing line in 2 seconds
. It begins to smoke at 5
. It smokes for a minute or so
. Then, is black, but no further visible changes
. After an hour it has changed resistance to 20 ohms
. After 5 hours it is up to 29 ohms
. After 10 hours it is up to 35 ohms
. Of course the V^2/R power is going down, but it wont burn out!
Just thought you might find this data point useful!
Bob, WB4APR
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[Al Wolfe]

Bob et al,
In my mis-spent youth I was involved with many projects that required a
squib, that is, an electrical igniter After a lot of trial and error we
settled on some very thin steel wire. Basically, we found some picture
hanging wire and discovered it was seven-stranded. Unwinding one of the
strands gave us a single thin steel wire that was perfect for our projects.
It would instantly explode with 120 volts applied and glow brightly at 12
volts before oxidizing and disintegrating.

73,
Al, k9si

Post by Robert Bruninga
We have been running a 0.25 Watt small resistor at 3.5 Watts ALL DAY and
it still wont burn out!

[Curt, WE7U]

Post by Al Wolfe
In my mis-spent youth I was involved with many projects that required a
squib, that is, an electrical igniter After a lot of trial and error we
settled on some very thin steel wire. Basically, we found some picture
hanging wire and discovered it was seven-stranded. Unwinding one of the
strands gave us a single thin steel wire that was perfect for our projects.
It would instantly explode with 120 volts applied and glow brightly at 12
volts before oxidizing and disintegrating.

Hah! In junior high or early high school I figured out that a 30-gauge wire-wrap wire made a better igniter for my Century rocket engines than the expensive igniter wires they sold... Saved money -and- made every launch successful. I also wired my launcher to the family's car battery instead (launched from the driveway), which also increases reliability.

I claim to know nothing about blowing up resistors on purpose... Really.

[Steve]

I tell my kids the stuff that I did as a kid would bring Homeland
Security down on me today. I'M AMAZED I HAVE ALL MY FINGERS TODAY! Steve
KB1CHU

Post by Curt, WE7U

Post by Al Wolfe
In my mis-spent youth I was involved with many projects that
required a squib, that is, an electrical igniter After a lot of
trial and error we settled on some very thin steel wire. Basically,
we found some picture hanging wire and discovered it was
seven-stranded. Unwinding one of the strands gave us a single thin
steel wire that was perfect for our projects. It would instantly
explode with 120 volts applied and glow brightly at 12 volts before
oxidizing and disintegrating.

Hah! In junior high or early high school I figured out that a
30-gauge wire-wrap wire made a better igniter for my Century rocket
engines than the expensive igniter wires they sold... Saved money
-and- made every launch successful. I also wired my launcher to the
family's car battery instead (launched from the driveway), which also
increases reliability.
I claim to know nothing about blowing up resistors on purpose... Really.

[Scott Miller]

I'm still looking for a reliable, reusable igniter design - if I'm going
to load 144 rockets into box launchers on the truck, I don't want to
have to replace all of those igniters after every firing!

Scott
N1VG

Post by Steve
I tell my kids the stuff that I did as a kid would bring Homeland
Security down on me today. I'M AMAZED I HAVE ALL MY FINGERS TODAY!
Steve KB1CHU

Post by Curt, WE7U

Post by Al Wolfe
In my mis-spent youth I was involved with many projects that
required a squib, that is, an electrical igniter After a lot of
trial and error we settled on some very thin steel wire. Basically,
we found some picture hanging wire and discovered it was
seven-stranded. Unwinding one of the strands gave us a single thin
steel wire that was perfect for our projects. It would instantly
explode with 120 volts applied and glow brightly at 12 volts before
oxidizing and disintegrating.

Hah! In junior high or early high school I figured out that a
30-gauge wire-wrap wire made a better igniter for my Century rocket
engines than the expensive igniter wires they sold... Saved money
-and- made every launch successful. I also wired my launcher to the
family's car battery instead (launched from the driveway), which also
increases reliability.
I claim to know nothing about blowing up resistors on purpose... Really.

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[Steve Noskowicz]

If you saw those paper match rockets I first saw back in the 60's...I used some small wire to ignlte them.
73, Steve, K9DCI



________________________________
From: "Curt, WE7U" <curt.we7u-***@public.gmane.org>
To: TAPR APRS Mailing List <aprssig-***@public.gmane.org>
Sent: Monday, September 8, 2014 10:59 AM
Subject: Re: [aprssig] Amazing resistors

Post by Al Wolfe
In my mis-spent youth I was involved with many projects that required a
squib, that is, an electrical igniter After a lot of trial and error we
settled on some very thin steel wire. Basically, we found some picture
hanging wire and discovered it was seven-stranded. Unwinding one of the
strands gave us a single thin steel wire that was perfect for our projects.
It would instantly explode with 120 volts applied and glow brightly at 12
volts before oxidizing and disintegrating.

Hah! In junior high or early high school I figured out that a 30-gauge wire-wrap wire made a better igniter for my Century rocket engines than the expensive igniter wires they sold... Saved money -and- made every launch successful. I also wired my launcher to the family's car battery instead (launched from the driveway), which also increases reliability.

I claim to know nothing about blowing up resistors on purpose... Really.

[n4lbl]

In the late '50s and early '60s I used Jetex rocket fuse wire. There was a
very fine copper wire inside and 12 V. ignited it reliably. I put the fuse
lengthwise through black powder in a paper tube.

Post by Steve Noskowicz
If you saw those paper match rockets I first saw back in the 60's...I used
some small wire to ignlte them.
73, Steve, K9DCI
*Sent:* Monday, September 8, 2014 10:59 AM
*Subject:* Re: [aprssig] Amazing resistors

Post by Al Wolfe
In my mis-spent youth I was involved with many projects that required a
squib, that is, an electrical igniter After a lot of trial and error we
settled on some very thin steel wire. Basically, we found some picture
hanging wire and discovered it was seven-stranded. Unwinding one of the
strands gave us a single thin steel wire that was perfect for our

projects.

Post by Al Wolfe
It would instantly explode with 120 volts applied and glow brightly at

12

Post by Al Wolfe
volts before oxidizing and disintegrating.

Hah! In junior high or early high school I figured out that a 30-gauge
wire-wrap wire made a better igniter for my Century rocket engines than the
expensive igniter wires they sold... Saved money -and- made every launch
successful. I also wired my launcher to the family's car battery instead
(launched from the driveway), which also increases reliability.
I claim to know nothing about blowing up resistors on purpose... Really.
--
Curt, WE7U. http://wetnet.net/~we7u
APRS Client Capabilities: http://wetnet.net/~we7u/aprs_capabilities.html
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