Soldering hell

I'd pre-tin the copper wire first and also pre-tin the connections on the LED's then you don't use any more solder when you make the connections. If you do need to flow some more solder into the joint then you heat the joint and apply the solder to the joint not the soldering iron tip. If the solder won't flow then in most cases the bit needs cleaning and tinning.

Keep the soldering iron bit clean with the tip covered in clean shiny solder. This cleaning and tinning of the bit is very important. Tinning the bit is just keeping it "wet" with a tiny amount of solder on it. As soon as the solder on the iron goes grey clean it and re-tin.

So strip wires dip ends into flux heat the copper up and flow a bit of solder into the wire.

Then a dab of flux on the LED terminals and heat them enough to flow a small amount of solder onto them. Next hold the pre-tinned copper onto the pre-tinned connection and heat them with the soldering iron. If necessary apply a bit of flux first.

In a lot of cases with good multicore solder you won't need to use additional flux very often. If you are making connections to existing solder that is a bit "grey" looking and not shiny then use flux. Ideally only make joints between shiny recently tinned surfaces.

Tinning = an old term I use for soldering.

While I'm prepared to be shot down over any of that because I have done very little surface mount work I have made up hundreds if not thousands of circuit boards on piece rate so have do have a bit of experience but it was a long time ago.

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Lumen wrote: »

Thanks. How's this look?

1.2 and 2.4mm chisel tips, 1.27mm 60/40 leaded solder.

Is flux needed if I'm using flux cored solder?

RE: flux no you don't need extra flux but its really handy for getting a really good joint particularly when things aren't working out and I've always found it useful when re-soldering old connections.

Didn't think you could get lead based solder anymore, when I was using a lot of it silver solder was always thought to be the best but don't know what is current thinking.

autumnalcore wrote: »

That soldering iron is apalling but unless you're planning on doing this sort of thing regularly a 25w antex style iron is more than sufficient. If you want to spend more I would just get one of the chinese t12 hakko knockoffs tips are dirt cheap on aliexpress.

If I was going to spend £130 I'd look out for an old metcal with tips and accessories, mine is about 20 years old did 13 of that 24/7 in a factory I worked in.

I've just about worn out my 40 year old old Antex soldering iron and was thinking of replacing it recently. I rarely do any soldering now but when I do its quicker to grab the old Antex than it is to plug in my chinese variable temperature soldering station which takes up too much precious work space and then needs to be put away after. I was thinking about a Weller W 61 Soldering Iron because I used to have the older W 60 but really can't justify the cost and will problably get the Antex linked below to keep handy in my electrical tool box.

If buying something like this https://www.amazon.co.uk/Antex-S582470-XS25-Soldering-yellow/ then I also recommend getting a stand like this https://www.amazon.co.uk/Antex-H400020-ST4-Bench-Stand/dp/B002GMN64C/

autumnalcore wrote: »

I never understood the weller fat, heavy, unwieldy cable and burns the hands off you after its been on for a couple of hours. 60w is too much for a lot of work.

Would never use that sort of soldering iron for very long. But its a handy size for the electrical tool box if you want one tool that can tackle a lot of types of work when away from the bench.

For the OP it would be overkill by a long way but would still do the job. All he has to do really is tin a lot of wires and then heat them for a few seconds to solder them to the LED circuit boards.

Funny you should say "burns the hands off you" as my old W60 was "retired" after it nearly burnt the house down . Not sure what finally went wrong with it but after a couple of minutes plugged in it would get too hot too hold and when I checked it out with a view to repairing it there was nothing but a blackened mess inside the handle.

Lumen wrote: »

As far as I can tell cat 5 uses 0.5mm (0.2mm2) wires. Is that sufficient to be taking 24V @ 5A? I guess it depends on the distance.

First of all are you really using 120 Watts of power on one cable?

Secondly I always associate cat 5 with a 0.5 Amp current capacity per conductor. Checking online indicates its a little higher than that but not much.

Certainly that cable in the picture is way to big for one LED. I suspect you could run more cables and split the lamps into say 4 groups and use thinner cable 1mm2 assuming your current plan is powering them one off each other in one group?