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Tips

New Wiring Loom Soldering

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tao724

Jedi Trainee
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I'm beginning the process of setting up a new wiring loom for a 1973 MG Midget. There are approx 10-12 lamp wires on the dash that need connectors added, as well as wire extentions that might be needed to be added to the front side lamps, head lights etc. . I have a bag of bullet connector nipples, the black bullet connector pieces, a hand held little butane torch, and two small tubes of pre-fluxed solder. (I also have a bunch of "shrink wrap" single piece connectors, which would be a whole lot easier to do, and much quicker, except, then if the dash was ever removed again, the wires they join would have to be cut).
Any how, my question is this; what is the correct way to get the wire soldered in the bullet nipple, using the little butane torch?
I was thinking, place the bullet nipple gently upright in a vice, put in two-three, 1/4" pieces of the solder, then heat the whole thing up untill the solder melted, then put in the wire to be connected with the tip 1/4' stripped of the plastic cover.
Is there a better way?

Thanks. :whistle:
 
"tin" the wire to be inserted into the connector first, set the connector over that then heat the side of the 'bullet' while touching solder to the hole in the tip. The solder will wick into the connector when the temp hits melting point. Feed it solder to fill. Allow to cool and Bob's yer Uncle.
 
But... butane torch? Get a soldering iron, it'll be a lot easier (typical 25-30watt should do it) You don't need that much heat to do connectors.

The "two tubes" of prefluxed solder has me a little concerned too. The "tubes" of prefluxed solder have been for pipe work and not electrical work. Be sure you're using rosin-core solder, other types of flux will lead to corrosion and possible failure of the connector. Radioshack sells small-core rosin-core solder for electronics, Lowes does too I think.

This might help too.
 
The butane torch is one of the little hand held soldering micro torches using a cigarette lighter fuel cylinder. Here is an example similar to what I have from WalMart. https://www.amazon.com/C-R-LAURENCE-20024...203&sr=8-28

I rechecked my tubes of solder.......they are labled rosin-core ( I used incorrect terminology). Thanks for the education.
 
I've got one of those. You can make it work but seriously, get a soldering Iron.
 
I'd concur... non-flame heat, directly applied to the side of the bullet.
 
When you get your soldering iron also get a stand, there are some that look like a springy thing that you put the iron into those are better than the ones you just rest the iron on. There should also be a sponge there.

Now when you start to solder, you let the iron heat up until the tip is fully heated, and melt a small amount of solder onto the tip until the tip is fully covered with solder. now wipe almost all of the solder off with the sponge (which should be slightly damp) This is called "tinning" the iron and you do this periodically to keep the tip clean and working properly.
Now put the tip onto the wire/bullet. The idea is to heat up the wire enough to melt the solder. If you melt the solder on the tip, and "drip" the solder onto the joint, it won't create a good joint.

If you did it right, the joint should be a fairly shiny color when you are done. If it looks grey, re-heat the joint since it is not properly formed.


You don't need it but I just got (at work) a nice top of the top of the line ...digital, computer controlled soldering iron with special miniature tips... It heats up instantly when you pick up the handle, cools off the when you put it down, and you can even get graphs of the tip temperature in real time on a PC when hooked up with the USB port.
 
Geez, Yiz!! I s'pose those tips allow ya to surface mount discreet IC's 'n such... without as much concern over heat sinks?

Sounds neat.


OH... and ya didn't mention tinning the end of the wire lead to be soldered into th' bullet connector. Then when heating the bullet to melt temp and introducing the solder to the hole in the tip, it will be drawn in, "wicking" into the bullet and form a proper joint. Done it hundreds, if not thousands of times over the last forty-odd years. No "cold" joint escapes inspection, either.
 
DrEntropy said:
Geez, Yiz!! I s'pose those tips allow ya to surface mount discreet IC's 'n such... without as much concern over heat sinks?

Sounds neat.
Click to expand...

It is meant for surface mount work, depending on what you are trying to solder there are all sorts of different shaped tips little tiny chisels, round, and even tweezers which heat up both sides at the same time (for those little tiny diodes and other such bits) very neat and quite expensive. I am using it to hook up a few wires directly onto standard CPU bumps or pins, the type that are supposed to be put into a holder. Soldering while watching what you are doing through a stereo microscope just makes it all that much more interesting.
 
Micro surgery!! VERY cool.
 
There's also bullet crimpers that one should use after the soldering.
 
tony barnhill said:
There's also bullet crimpers that one should use after the soldering.
Click to expand...
??? Why would you crimp <span style="font-style: italic">after</span> soldering? I would think that would damage the joint, causing the solder to separate from the connector.
 
So, when would you crimp? The few I've done, I solder, then crimp & then let solder run down into the connectorconnector.....probably not the correct way to do it.

But, you have to use the correct crimper for the bullets.
 
Nope - you crimp first. Crimping afterwards only crushes the solder, then when you reheat it it flows out. Crimp it first, make it a decent crimp, then solder it.

A lot of people don't solder crimp connectors at all, but to me it ensures no moisture is going to get in there and cause problems later.
 
Learned something new today!
 
I'm strictly a solder guy. Crimp fasteners are cheezy IMO. Squeezing solder after it's been set creates a fractured joint. As does wogglin' around th' wire as th' solder cools (as th' video guy does). If AIR is eliminated from th' connection there's less chance of dissimilar metals goin' goofy in time. "ScotchLoks" and other crimp or "casual" connectors are the enemy. The interface between copper and dissimilar metals like th' bullet connectors should last past your lifetime, solder is the only thing I know of that'll DO that. Crimping alone is allowing atmosphere to play a part. Crimping *before* solder is unnecessary. It just dams up the backside of th' connector.
 
tony barnhill said:
So, when would you crimp? The few I've done, I solder, then crimp & then let solder run down into the connectorconnector.....probably not the correct way to do it.

But, you have to use the correct crimper for the bullets.
Click to expand...

<span style="font-weight: bold">NO! Never crimp AFTER you solder! </span>
Frankly crimping alone, done with a proper good quality tool performs a "mechanical weld" and soldering after is kinda redundant. But crimpimping after a joint is soldered can cause embrittlement of the solder joint and probable cold joint, high resistance failure.
 
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