I will say something on top, due to my experience of avionics made by amateurs that I have to fix later.
If you have:
1. Correct high quality, original crimp’s
2. Correct approved wire
3. Correct approved tool (original one)
CRIMP
If you haven’t all this 3 points, change connector and solder it i.a.w. best soldering techniques you can achieve.
Sad amateur reality is that most of pseudo-avionic guys haven’t expensive crimpers or correct materials, they try to crimp incorrect wiring by pliers or incorrect tools and effect is really dramatic. Then it’s better when they go to better known ground of soldering.
Personally, when I’m finding exchanged garmin or other crimp connectors to solder ones. I always advise customer of additional cost as I’m going to go back to factory standard but worst I have seen is improper crimping – it will NEVER work properly!
Would you consider the crimping tools by JrReady acceptable compared to the Daniels ones? At least Steinair promotes and sells them to customers although they mainly target the homebuilt scene as far as I understand. On the other hand homebuilders seem to develop increasing professional skills when wiring their avionics.
Peter wrote:
Also avionics wire is not always easy to solder.
Something just reminded me of this thread, I’m building a big linear power supply for hobby projects, and since I got several reels of avionics wire relatively inexpensively a couple of years ago, I tend to use it for a lot of things.
I also recently got a new rather pricy Hakko soldering station, including some fairly large tips. Given this is a project for something that doesn’t move (for things that move I prefer to crimp, for things that don’t move I prefer solder) I soldered the rather thick (I think it’s 12awg) wire onto the rectifier board. It soldered very easily with the large tip – the nice thing about this soldering station is the heater and temp sensor is part of the soldering iron tip, so it has a better chance at heating up things that tendn to wick the heat away, and this rather thick wire soldered very easily – I wouldn’t have had a chance soldering this stuff with my old soldering station (I tried in the past and failed!) So if you’ve got good soldering tools and an appropriate sized tip you’ve got a much better chance for success.
Firstly you need to use leaded solder for hand soldering. At work we tested at least 10 brands of unleaded (mostly SAC305 variants) and only one was really good: Almit from Japan. Super pricey at around £70 for 500g reel. The flux in most solders is just no good. We do all prototype work (hand soldered and reflow SMT) using 60/40 leaded solder. Especially good for SMT using a simple chinese IR oven because it melts at a lower temp.
SMT in production works well enough with SAC305 these days… with reflow ovens costing tens of k.
Secondly avionics wire degrades over the years and eventually becomes really hard to solder – here. I have Raychem wire here which is nowhere near 25 years old and is already hard to solder. Another reason for crimping: you can use up old wire 
Best wire for hand building high quality gear is PTFE insulated and the wire is normally silver plated. Very expensive…
Peter wrote:
We do all prototype work (hand soldered and reflow SMT) using 60/40 leaded solder
Can you still get leaded solder? I thought it was banned many years ago. (All the solder I’ve got for many years is without lead.)
Yes of course, and no ban at all. Only finished products which claim ROHS compliance (other than by exemption) need to use unleaded.
In practice anything marketed needs to be ROHS, except military (which demands >2% leaded for reliability) and (I believe until recently) medical. Not sure what happened to the various exemptions like Control and Monitoring; these were extremely useful
While Peter is right, it has become a real pain to obtain the good old 60/40 as a private individual, in the EU at least. Since it now must only be sold to customers who have been trained in the handling of harmful substances (probably a 25 page web based training about washing ones hands and not eating in between touching the stuff) all the shops will sell it only B2B.
Yes; trade suppliers sell it freely.
@Clipperstorch wrote:
it has become a real pain to obtain the good old 60/40 as a private individual
It seems to be a specifically German thing. Here in Czechia, classical 60/40 or 63/37 solder is sold freely. For example, this e-shop sells to Czechia, Slovakia, Germany, Austria and France, and the version for Germany is different from the rest.
I see now that one of the major electronics distributors in Sweden (ELFA Distrilec) also sells 60/40, apparently without any restrictions. Guess I’ll buy some.
But the German version of the same web shop indeed doesn’t allow private individuals to buy it – only companies.
