21 replies to this topic

[nicklouse]

Well your eyes and fingers.

Terminations.

What is the correct way of fitting them.

For many years I have just crimped on the plastic insulated terminals.

Bug I am no redoing the harness (if you can call it that) and I have seen how the terminals can come loose etc in time.

Now I could carry on doing what I have always done or ask you guys about the correct way.

I will be using non insulated terminals and just crimping them. And then adding some heat shrink.

I don't think that solder would be any benefit but I do seem to remember some terminals being soldered over the years.

Am I missing something or.....

[WiredbyWilson]

I would and do insist on crimping and soldering every single connection. And I'd fit the correct hard plastic covers as well. The insulated terminals are a bodge and quick fix. If you are taking the time to build a harness then crimp, solder and cover.
The reason I solder every terminal is that it prevents water ingress into the connection, and also a much better connection between the wire and the terminal. Solder can't rust or rot if done correctly.

I also only use adhesive heatshrink, a lot more expensive but again seals the bare wiring from water ingress.

Some will argue that new car looms aren't soldered, correct, but new looms are no where near as exposed as a mini nor as poorly designed.

Do it right, do it once, do it properly.

Wiredbywilson

Edited by WiredbyWilson, 05 September 2015 - 09:25 PM.

[nicklouse]

Ok.

On the soldering. This is after crimping or instead of?

That is to say the wire part not the insulation part as that has to be crimped.

Do you crimp the wires and then solder?

I am more interested in mechanical failure and integrity.

Race car not road car.

[Carlos W]

Crimp then solder I believe.

 

There's a couple of pictures at the end of my build thread of Davids work.

[ChopperHarris]

"tin" the wire, crimp, solder, heatshrink....sufficient length down the wire as some folks will say the solder makes the connection brittle

[nicklouse]

"tin" the wire, crimp, solder, heatshrink....sufficient length down the wire as some folks will say the solder makes the connection brittle

Not sure about the being its of Tinning the wire first as that can I believe reduce the efficiency of the crimp?

[ChopperHarris]

I can see the logic in that. However that's what a Royal Engineer taught me.

[monkey]

Tinning before crimping will help the solder get into the joint rather than just on top of it

[mini93]

Many the military looms I used to produce were required to be soldered.

 

Make sure to use good quality solder with Lead... If you ever heard about X-Boxes and playstations failing, often its because they used lead-free solder (environmental reasons i'd guess) The lead giving a degree of flexability and makes it less prone to cracking or failing

 

and +1 on the tinning, Can be difficult to solder thicker wires; getting heat into the wire ensuring the solder doesnt sit on top rather than making a secure connection. re-melting the tin sucks any additional solder around the joint (and dont have to worry about melting the insulation)

[dklawson]

There are advocates of "crimp only" and they cite anecdotal evidence of "the military does this in the field" or "such and such car company only crimps".  

 

We deal with connectors at work on a daily basis for our products.  We use both solder and crimp connections.  As one of our connector suppliers told us, crimp connections in the military are often mandated to get consistent results quickly from personnel who have different skill levels when it comes to soldering.  In short, crimping is done for expediency and consistency and not necessarily because it is best.  That said, a well done crimp can be highly reliable... but most of us DIY mechanics don't necessarily have the best crimping tools.

 

As others have advised you above, tin the wire, crimp the wire in the fitting (mainly to make soldering easier) then solder.  Minimize the solder on the stripped wire during tinning and get the heat in and out quickly when soldering the wire in the terminal.  You want to avoid having the solder wick down very far inside the wire.  Cover the joint with heat shrink tubing.  As WiredByWilson suggested, the adhesive lined heat shrink is really nice for this type of work.

[nicklouse]

Guys as normal some great info and reasoning behind what can be read on the internet where people have relied on google for an answer but have not got the full picture.

No I just need to decide what I will actually do.

But there is time for that as I need to make my switch panel assy first..

[hazpalmer14]

Wouldn't listen to a royal engineer, think they know what they are on about. Yet they still get the REME to fix their kit for them.  

 

But i'd probably crimp and then solder. Then as per what wired by wilson said we use the adhesive heat shrink, and do it above and below any joins we make. 

[nicklouse]

Still not got around to doing anything as I need to make up the boxes to hold the stuff.

But it has brought me to something else.

Instead of the adhesive heat shrink has anyone tried the rubber paint that can be used as insulation?

Just realised I have a tin that I used for something totally different.

[dklawson]

I have used the brush-on liquid vinyl a few times.  It can do the job... a bit.  You need to apply several coats to get a decent build up when used alone.  It also is not very helpful for covering female spade terminals.  What I have done to address this is to put a bit of the liquid vinyl on the wire and slip "regular" heat shrink over the terminal and the end of the wire where I applied the liquid vinyl.  When you shrink the tubing it will sort of bond with the liquid vinyl.  However, it's a bit messy as the vinyl will boil under the heat so you will want to wipe off the excess as soon as you take the heat away.

[nicklouse]

Kinda what I was thinking about the multiple coats.

Might just go back to my original plans. Crip,solder and slip on the covers. Might add the paint to the engine bay terminals. But not planning any wet racing yet as I don't have any wets yet!