View Full Version : Soldering Nipples

profqwerty - n/a
4-Aug-08, 01:27 PM
I had a solder nipple come off whilst the hover was in storage, and trying to put it back on is proving a pain in the ass.

I've cleaned the cable, and trying to get any solder to stick to it is absolutely impossible. It's like the cable's solder resistant! It's old style solder, leaded type.

I initially thought maybe the iron wasn't hot enough, so tried it on the gas bbq, which easily melted the solder. However the solder always just drips off the cable! It sticks jsut fine to the pliers I'm holding the end with!

Can anyone help? Or is there a solder free solution? This end goes into my throttle cable splitter.

Many thanks,


Nick Long - n/a
4-Aug-08, 02:06 PM
Obvious questions, Toby, but have you degreased the cable and are you using flux cored solder?

I've generally had no problems soldering nipples onto cable, but it can be almost impossible if the cable is even slightly corroded. With new or clean cable, you should be able to tin it (technical term for getting the solder to adhere and flow properly over the surface) with ordinary flux cored solder.

If it is only a little dirty, then using some extra plumbers' flux paste can often work.

If the cable is more than a little dirty, then you probably need to clean it with acid first - to be honest at that stage it is better to either get a new cable or change to a crimp on nipple.


profqwerty - n/a
4-Aug-08, 02:26 PM
I degreased it with brake / clutch cleaner, then under a high flame it burnt a bit which I assumed was the remainder grease disappearing. The cable's gone a yellow colour - is it possible that it's zinc plated?

I think i'm just gonna weld a blob onto the end. Could go either really well or just melt the whole thing http://hovercraft.org.uk/images/icons/smiley_icons/icon_rolleyes.gif wish me luck!

jon_curtis - n/a
4-Aug-08, 05:12 PM
assuming you have soldered to it previously, and its not a set lenght cable you have bought? I got a cable like this from halfords once, and took me a while to realise, the cable was stainless and therefore would not take solder.

too much heat and your never gona solder a nipple on, if you burn the cable to where it is discoloured then solder will not stick to it. cut it back and start again.

you would need a beafy iron to get the solder to flow, if its a normal iron, i doubt its hot enough! i always use a small gas torch to solder cables, if you get in red hot tho, thats it, it will not stick.

old lead solder will flow the best, lead free solder is pants and does not wet out the same as lead solder.

i heat the cable just below the nipple, so the heat flows up into the area you want to solder the nipple on, once the nipple sat on the cable starts to wet the solder, take the heat off and on untill its flown into the wire and thru the nipple. carefull not to get it too hot!

there is a nack to it, and you need clean wire and clean nipples. i drill out standard nipples so they are a little over size, so you get LOTS of solder filling the gap!

it sounds to me as you have got the wire too hot, burnt the passivate caused oxidization and you wont get anthing to stick!

welding a blob on the end, is also a bad idea! you will melt the cable back and it will not hold if you do get a blob to stick!

best to do it properly, either cut it back or replace the cable.

kevinf - n/a
4-Aug-08, 08:22 PM
Lots of cable inners are stainless steel. They can be very difficult to solder because stainless generally has a very thin oxide layer which is difficult to remove. Resin based fluxes are next to useless, you need to use an acid based flux to clean the wires of oxide deposits. Phosphoric acid based fluxes are best as any residuum is fairly innocuous. Hydrochloric acid based fluxes will need to be thoroughly cleaned afterwards otherwise they will corrode the cable. Stainless also has a fairly poor thermal conductance so you need a large capacity soldering iron and plenty of patience.

I make my own nipples from copper rod. Drill through the rod to suit the wire and then counter drill one side to open out the hole with a larger drill. (I generally don't cut the nipple off the rod until I've soldered the cable in, it gives you more to hold onto) Push the cleaned wire through the small hole and then untwist the end of the cable so it bushes out. Gently pull the nipple up to the bushed out part and support it all in a vice or mole grips so that your hands are free. Get plenty of flux into the end of the wire and the nipple and apply the iron for a minute or more so it all gets nice and hot. Brush on more flux and then apply the solder. The heat in the nipple and the wire should melt the solder and capillary attraction will pull it down into the joint. Keep the iron in contact with the nipple until the molten solder fills the hole, then remove the heat and do not disturb the joint until it has hardened. Hold the nipple in the vice and dress the end of the cable with a sharp file to bring it flush with the surface of the nipple. By opening out the end of the wire the surface area of the soldered joint is vastly increased making it almost impossible to pull the nipple off the wire - it acts a bit like a plug in a tapered hole.

Good luck


profqwerty - n/a
4-Aug-08, 08:58 PM
I'm fairly sure that it's zinc galvanised cable, and will not solder.

At the moment I don't have any solder left, and the soldering iron is like 40W. The gas bbq makes it waaay too hot.

The yellow colour is the zinc oxidising in the heat of the gas flame, once this happens nothing will stick to that!

By weld a blob, I held the cable vertically downwards, then put the welder onto low power / low flux speed. I buzzed it for <1sec and as the cable melts it forms a fat blob on the end. A quick blow sets it solid. In theory there's no chance that it'll come off as it's part of the cable! (Ha! Famous last words)

Incidentally it also burns off the zinc, so I can then solder the nipple above it!

The only drawback is that it's very difficult to form the blob exactly where you want it as the cable does melt back, but to varying lengths!

I'm going to do some testing tomorrow, see how much strain one can take and maybe replace the other nipples with these.

I'll go get some more solder from maplins and try that soon.

Mart366 - n/a
6-Aug-08, 05:36 PM
I used to buy screw on nipples, and then drip solder into the end where the cable enters the nipple.


jon_curtis - n/a
6-Aug-08, 06:01 PM
The only drawback is that it's very difficult to form the blob exactly where you want it as the cable does melt back, but to varying lengths!

I'm going to do some testing tomorrow, see how much strain one can take and maybe replace the other nipples with these.

The heat effected zone,close to the blob of weld will be brittle, it might take the strain initially, but will suffer fatigue and eventually fail! i'm sure you will notice the end of the cable that glowed up and burnt back will be stiff and blackened? most certainly buy getting the wire hot enough to burn back a section you will have greatly effected the mechanical properties of the material, in that area and not for the best!

profqwerty - n/a
6-Aug-08, 08:02 PM
You are correct - the individual strands fuse together into a single wire. The location of this one is OK as the wire does not bend for a few cm from the end, but it is hardly satisfactory. I'm trying to get hold of some normal cable + nipples and start from scratch with a uniform system http://hovercraft.org.uk/images/icons/smiley_icons/icon_rolleyes.gif