Fusible Link

[cantflip]

As a B.S.E.E., I can only affirm your recommended solution for the present. Engineers are supposed to design practical solutions, except in Germany, where they always have their heads in the clouds. (Voltaire)

I only assert that if practical, DO solder the connection, with care against allowing it to "wick" up the strands of your link beyond a few millimeters IF you want a really good connection and IFF you can do it neatly. Otherwise, crimp and be done.

Those bulkhead connections were BAD **** the day they were first excreted from some corporate engineer's R-complex. Engineers oft are forced to choose "lesser evil" options due to constraints imposed by management and sales. Such was this monstrosity. Molex connectors are no better and have afflicted mankind since the same period.

I advise all and sundry to get a nice set of screw terminals with at least enough connections to replace what you're using in the bulkhead, then re-route your wires to those. I did just so on a 1959 International which used some awful mess to go from under hood to inside and this is what I WILL do with Mathilda ASAP. I've already done away with the main power leads, brake lights and a couple others, eliminated the idiot lights in favor of mechanical sensors and sleep better for it. Sometimes an electrical fire can be serendipitous.

You might even go so far as to install nice fuse boxes at the firewall to serve for termination AND protection. I like screw terminals. Safe. Visible, reliable, allowing plenty surface area to assure good contact. Use rubber grommets to protect your wires from nicks from the sheet-metal.

There is a practical aspect to your suggestion that does not escape me... unfortunately, I think it would be viewed by many as too "shade tree" or whatever other term they choose to describe the appearance. The shame is you are right, it would be an ideal way to create a nice clean contact and have excellent serviceability. I would want to find a very good waterproof housing for it though... And maybe the appropriate Nye grease to kill fretting...

 

[furyfever]

That's definitely solder all right...

I think everyone figures you would do the typical amateur soldering job that wicks the solder up the wire and changes the resistance. Since you worked for Xerox, you've probably been through a "soldering school" or at least know what you are doing so you can do it the right way.

You're probably a clever enough guy to reuse those terminals too.

How did you know John? Now I just got to get Advance Auto to cooperate!

Bob

 

[cantflip]

How did you know John? Now I just got to get Advance Auto to coooperate!

Bob

I would expect someone to have it on the shelf... try NAPA or look at the "HELP" display... there should be something... I am sure of it...

 

[Big_John]

How did you know John? Now I just got to get Advance Auto to cooperate!

Bob

LOL! I figured that you probably took a Mil-Spec soldering course somewhere along the line.

You can take the yellow tag off the old wire too and move it to the new wire. It will look "original" then.

 

[furyfever]

Advance Auto did cooperate today. The fusible link came in and I was able to make a pigtail up this afternoon. I wound up trimming 1.75" off the 7.5" length = 5.75" (about 1/4" longer than the original wire) and then crimping on the used terminals. Soldered the #16 fusible link wire (quickly) just at the very ends so it wouldn't wick inwards. It worked out well and car is functional once again. Here's a few photos. Didn't think to swap out the black rubber tag for the original yellow one though. Good idea but still...looks way better than how I first planned on fixing it. Thank you again John...for all your help. The photos of the terminals you posted were the key to fixing it right. That showed me just how to get them out of the connectors. Never used this type of terminal at Xerox obviously... Thanks to everyone for your patience and for all the time you took to explain things to me. Now I know the WHOLE wire is the fusible link...not just the center that melted/burned up.

Bob

 

[commando1]

Jeezes. How long was that package languishing at the warehouse...

 

[1966newport]

any 16 guage link would work

 

[Big_John]

any 16 guage link would work

Yes and no. The biggest difference with the fusible link wire is the insulation. The plastic insulation on a regular piece of wire will burn or melt. The fusible link insulation is designed to contain the melting wire.

So, yes, any 16 gauge wire would work to protect the circuit, but then you take your chances with burning insulation if there is a short.

 

[70_NPORT]

Yes and no. The biggest difference with the fusible link wire is the insulation.

So, yes, any 16 gauge wire would work to protect the circuit, but then you take your chances with burning insulation if there is a short.

Ugh...had to do this a couple years ago...got stuck on the road...and yeah after researching it I found out the insulation is different then standard wiring...but its an easy fix. You prob wanna figure out why your FL burned up in the first place (unless you already have...maybe I missed it in your thread).

 

[1966newport]

i meet they should have had a gm or ford16 guage fusable link in stock

 

[rexus31]

i meet they should have had a gm or ford16 guage fusable link in stock

GM did not use a Fusible Link, they used a Resistance Wire in the harness. Not sure about Ford.

 

[Big_John]

i meet they should have had a gm or ford16 guage fusable link in stock

Gotcha.

 

[saylor]

./digs up old thread

O Wise and Venerable Forum !

re: MAD ammeter bypass / Nacho parallel wiring technical details:
1.) crimp + solder + shrink ALL connections
2.) DON'T solder any connection that is a fusible link

3.) wait, what ?

OK how do i splice 10ga wire to 16ga fusible link then? crimp + shrink only?
And - whats a clean way to get 2x 10ga wires joined to a 16ga fusible link?

Please help me try not to die -

- saylor

 

[saylor]

12-10 AWG Power Phase® Yellow Polyolefin Sealed Crimp & Solder Butt Splice Connector | Fastenal


i was at fastenal looking at these. asked dude if anyone uses them / if they are worth a ****. he said a local mfg. co. here in garland this is all they use on their AC units they build. i told him I was going to use it for an alternator wire on a car - he said no problem.

what does the forum say? anyone tried these bad boys?

i REALLY REALLY suck at soldering, so I'm trying to cheat. these have to heat up to 1000* for the solder to flow per pkg instructions.

 

[Big_John]

2.) DON'T solder any connection that is a fusible link

3.) wait, what ?

OK how do i splice 10ga wire to 16ga fusible link then? crimp + shrink only?
And - whats a clean way to get 2x 10ga wires joined to a 16ga fusible link?

Please help me try not to die -

I try to not have anyone die.. LOL.

The reason for not soldering your fusible link is pretty simple. As you solder the wire, the solder will wick up the strands of wire and cause two problems. First is it won't be as flexible, and more importantly, it will change the value that the wire will burn up at.

The fusible link has got a little science to it. It's a specific type and size of wire. You don't want to change that by adding solder to the mix.

i REALLY REALLY suck at soldering, so I'm trying to cheat. these have to heat up to 1000* for the solder to flow per pkg instructions.

Right there... If suck at it, you really don't want to do the fuse links... In fact, you may not want to do any soldering of connections. I'm not going to start a "solder v. crimp" argument here. I will state that you can't solder any connections in airplanes... All crimps.

The issue is that the wire is less flexible at a soldered joint and can break.

In a car, that breakage isn't gonna knock you out of the sky and there may be something to be said for soldering and crimping... Provided you don't, as you say, suck at soldering. LOL

I use a lot of butt connectors with no insulation. Occasionally, I will solder the connection too, but it's usually just a crimp. I'll put heat shrink tube over it and I'm done. Any terminals ( like a ring or a blade) get crimped and I also buy bare ones, or strip the insulated ones and use heat shrink.

The connectors shown work well. You don't have to buy a $100 bottle of them... Most parts stores carry them. I've used them in trailers and things like that and they work great.

Now.... Let's get to soldering.... Is your tip tinned correctly? What kind of solder are you using? Flux? What kind of iron?

 

[Gerald Morris]

I use small split bolt "kearney" connectors for fusible #12 to #8 wire, or 10 to 6, anything larger. You have to tape these over WELL once yopu secure the nut pressing the wires together, but the advantage lies in not having to keep cutting your main conductor to crimp a fresh fusible link to it. Smaller stuff I use shrink wrap + bare copper crimp connectors.

 

[ktuuri]

If you want the original look, you are on the right track.
But if you want better and original look does not matter, just go to any auto store and get an inline fuse holder which accepts the newer (80s+) fuses and wire that in place of your fusible link. You can than put in any size fuse you want, if a fuse blows in the future, all you have to do is replace the fuse, maybe even step it up one size bigger.
I did this in my 90 Dodge RV when I blew a fusible link. What a pain that was, so many fusible links in that compared to the older mopars.

 

[Big_John]

If you want the original look, you are on the right track.
But if you want better and original look does not matter, just go to any auto store and get an inline fuse holder which accepts the newer (80s+) fuses and wire that in place of your fusible link. You can than put in any size fuse you want, if a fuse blows in the future, all you have to do is replace the fuse, maybe even step it up one size bigger.
I did this in my 90 Dodge RV when I blew a fusible link. What a pain that was, so many fusible links in that compared to the older mopars.

While both a fuse and a fusible link are used to prevent too much current from damaging the circuit, the fusible link works a lot slower. A fuse is designed to quickly melt and disconnect the circuit. A fusible link, on the other hand, is used because it is more forgiving of short spikes in current.

While I don't see that it would hurt to have a fuse in the main circuit, you are really setting yourself up for a failure that will shut down the entire car.

You can than put in any size fuse you want, if a fuse blows in the future, all you have to do is replace the fuse, maybe even step it up one size bigger.

Any size fuse? Step it up one size bigger? That's a good recipe for disaster. The fusible link is sized to the wiring it supports and it's pretty simple to figure out the proper size. It's four wire gauge sizes smaller. Guessing at a fuse size is a good way to have a smoldering car on the side of the road.

 

[saylor]

+ 1 with mr big john.

we are trying not to die around here, and swapping the link with any kind of circuit breaker or fast blow fuse is ungood.

i see it on every site that talks about fusible links though, it seems to be common to do.

too risky in my opinion to use fuses, i will put fusible links back in.

+1

- saylor

 

[Gerald Morris]

STICK WITH FUSIBLE LINKS! Slow-blow (or Slo-Blo) breakers are a distant second choice for automotive overcurrent protection, but for critical need circuits, fusible links offer both protection against overcurrent AND protection against MOMENTARY TRANSIENT SURGES caused by NORMAL OPERATION.