To solder or crimp

[biggee]

I have been trying to solder two wires, one the ignition (quite thick) the other is the immobiliser(quite thin) the problem is I can't seem to get enough heat into them with an 100 watt iron to melt the solder. Has anyone had any similar experience and if so how did you overcome it.

[gooner1]

What grade solder are you using

[biggee]

Not sure it just came with the gun

[biggee]

diameter 1mm Sn 99.3% Cu 0.7%

[Brianmoooore]

Ditch the lead free eco rubbish, and get yourself some decent flux cored lead/tin stuff! You cannot make reliable joints with that rubbish.

[biggee]

So does the none eco stuff melt easier?? or is it just more reliable.

[Speedtouch]

It melts real good, and doesn't give brittle joints like the lead-free shite.

[Brianmoooore]

It melts at a much higher temperature, with a sharply designed melting point. This gives rise to stresses as it solidifies, and the slightest movement at just the wrong time will make the joint fail.
The older lead/tin mix (40:60) melts at a lower temperature, softens slowly as the temperature increases, and similarly allows stresses to dissipate as it hardens. The surface tension of the older stuff is much higher than the lead free stuff, so you get mush more solder built up around the joint, making it much stronger.
No, the eco stuff is far from being more reliable.
Buy up the lead stuff, while you can still get it!

[aeberbach]

Your iron is probably the issue. I have been using lead-free solder exclusively for about four years now and have soldered everything from tin plate to surface mount to auto wiring, but I agree it is less forgiving than solder containing lead. You need an iron that gets hot enough and stays there - so it needs excess capacity to pump into the tip once you apply it to something that is going to start sucking heat out of the iron, but it needs good thermo control not to be too hot all the time. There are dozens from Hakko, Weller, Cooper Tools (i.e. Weller) and others that fit the description. A 100W iron designed for sheet metal or leaded glass work is not what you want - the tip is probably way too big for a start. Almost any kind of solder "gun", especially the kind that dispenses solder automatically onto the tip, needs binning. A gas-powered iron can be OK but only if you allow more time to heat the joint properly and if the item being sodlered isn't mroe of a heatsink than the iron can overcome. If you have to put the solder on the iron to get it to melt rather than on the joint you are either not giving the joint enough time to heat or your iron isn't up to the job. Another thing, solder looks like welding but it isn't. Any joint relying on solder for mechanical strength is a fault waiting to happen especially in a car.

If you are not going to devote time to learning to solder and invest in the right tools and heatshrink etc., crimp instead. It was good enough for BMW and the right tools cost you far less than soldering and it is a lot easier to get right.

[biggee]

Thanks for the comprehensive answer, I originally bought a 30 watt iron and this was useless, I didn't really want to spend a fortune on an iron as it's pretty much a one off job, so second time round I have bought a draper kit which contains the 100 watt iron and solder sucker etc, I suppose I will try the proper solder first before deciding what to do next, it's just annoying messing about with what should effectively be a 5 minute job

[Speedtouch]

A 30W iron should be fine, so long as you use proper lead-mix flux-cored solder. Do yourself a big favour and ditch the lead-free brittle garbage.

When soldering, the most important thing is to 'tin' the iron bit with a brief wipe of solder prior to commencing any soldering; this will assist with the heating of the joint sufficient so that when you apply the solder, it flows freely into and around the joint. Use just sufficient to accomplish the job; too much creates a nasty mess and usually a 'dry' joint, as it takes forever to cool and set.

[Brianmoooore]

A 25W iron is all I normally use, but never with the lead free stuff.

[Speedtouch]

Same here, an Antex XS usually, The so-called eco-friendly lead-free stuff is a misnomer since you have to use a higher temperature (more global warming!) to melt it in the first instance, then the brittle joints will last less time (creating more waste and pollution = more landfill).

Keep it real, keep it old school cool