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MG Midget and Sprite Technical - bullet connectors soldering

Anyone have advice on how best to solder bullet connectors. I am putting in a used wiring harness on my 71 midget. Going good but I need to install several bullet connectors.
I read somewhere you heat the wire and put solder on it then put the bullet over the soldered wire and heat the bullet and let solder go down into the hole in the top of the bullet.
Thanks
Ken Bargeron

I use a piece of wood with a hole drilled in it, only deep enough so the bullet sits about halfway in. I then fill the bullet with solder & then push the newly trimmed wire into the molten solder, allow to cool. The pioece of wood is like having a third hand, also if you have lots to do you just drill more holes.

Kevin
K Grice

Ken, are you crimping the bullet connectors?
Ddraig

First, make sure that the bullets are solid brass to make a good soldered joint.

The soldering iron needs to be 40/50w or a bit more - the small 25w irons will take forever! The tip needs to have a flat side, the round, pointed type will not work for this application.

The solder need to be the pre-fluxed electrical type, not plumbers.

Make sure that the soldering iron tip is cleaned and 'tinned', i.e coated with solder. Will need wiping on a damp cloth regularly to keep clean, then 're tin'.

Strip the wire back about 10mm (3/8") and slip the bullet over the end. The wire should protrude slightly through the hole in the bullet, if not strip enough so that it does.

Do not 'tin' the wire first as it makes it near impossible to get into the bullet. By having the wire bare, you can make sure that it goes into the bullet properly - expecially if you are fixing more than 1 wire into a single bullet.

Apply the heated flat side of the iron to the side of the bullet, and at the same time apply the solder to the end where the wire is protuding. After a few seconds the bullet and wire will become hot enough to melt the solder, which will be drawn inside the bullet by capillary action. When done, trim the excess wire with side cutters.

Ahah - iron + wire + solder = 3 hands!!??

I set up the solder from the roll so that it is the 'fixed' part, leaving just the iron and wire to manipulate (the bullet is already on the wire).

I do not crimp bullets, as they can be more difficult to get into the connectors, and also if they distort they do not make such a good connection. Also the crimp can 'relax' and produce a bad connection, or worse the wire pulls out!

Sounds complicated, but once you get going it's really quite quick!
Richard Wale

Sal asked the question above.
She says to crimp and just a touch of solder to seal it. But the best way is to use an insulated bullet. No soldering involved.
(She's made thousands of harnesses, one big customer was Caterpillar)
Ddraig

Also, be aware that elderly wiring tends to oxidise at the ends, even part way up under the insulation. This can make it very difficult to solder. I've found that it is often best to cut an inch off the end to get to 'fresh' wire and extend the loom with a new piece.
Allan ('76 Midget 1500)

I wonder if it wouldnt be easier to soulder all the bullets at one time with about 8"-12" of wire first, then soulder that onto the wiring harness, that way you can use K. Grices Idea of a block of wood, and your not hanging upside down trying to soulder, in a dark, tight, hidden, spot.


prop
Prop

Make sure you solder at good temp and burn away all the acid. Soldering in automotive is very prone to condensation/temp variations that can causes premature fails.

As Ddraig says, properly crimped wires can be very reliable.

I remember the proper days of computing - back-planes never used soldered connections from wires to back-plane pins, but rather the wires were wrapped on the pins with a special tool. Happy days!! (Mind you, changing the wiring required a very good process, since a missed connection or change was _very_ difficult to find in the maze of wires...)

A
Anthony

If you do solder, take care not to apply too much solder as this can wick up the wire and create a stress point. This can cause the wire to break if the harness is flexed regularly or vibrated. I would go for crimp joints where ever possible.

Dv
Dave

Thanks for the replies everyone... to make things even more complicated I broke my arm about two months ago and I still only have limited use of my left arm. But I am still making progress on my restoration (slow progress but progress just the same). For some wires that I cannot get to very well I am in fact doing a wire to wire solder with a bullet already soldered to the end of the installed wire. Hopefully I will not have trouble with this. I am only doing that on a few wires.


BTW I am not doing any crimping...
Ken Bargeron

This thread was discussed between 19/02/2008 and 21/02/2008

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