Hi all, I'm playing around with some relays and need some guidance.
I have this relay:
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It's not going on a circuit board. I'm planning to just solder some wires to the contacts with a 25 watt pencil iron.
Do I need to use a heat sink to protect the relay coils and contacts inside? Bob
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Rich Grise
Not if you use small wire (maybe #22-24), wrap it around the end of the post, and don't linger too long (use a hot enough iron, and solder it quickly; if you get a cold joint, let it cool completely before you try again.)
Make sure everything's clean and shiny, and use a good flux-core solder, like Kester 63-37, which RS also has.
Have Fun! Rich
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John Popelish
Probably not. I think this unit is designed to be soldered onto a printed circuit board, so it is designed to have its pins soldered.
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jasen
No heatsink is needed. If you can make the joins with less than about 5 seconds of direct heat on each pin (which shouldn't be difficult) the relay will survive.
Bye.
Jasen
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Ross Herbert
Many of the cheaper relays have their pins in plastic which won't take direct soldering. Anything more than 2 seconds will see the pin being soldered wilt sideways. If this happens you have to let it cool and then judiciously apply more heat while straightening the pin and holding it with pliers for a few seconds until it is once again in its normal alignment. They are fine when mounted to a pcb and up to 4 or 5 seconds can be tolerated because the copper traces act as a heatsink.
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Bruce
"AB" wrote;
Hi Bob,
I've use this same relay for several projects, and never had a problem with soldering wires to leads or mounting them on boards.
Regards,
-Bruce
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Rich Grise
I'm sorry to bust your bubble, but this is really more a matter of technique, albeit 2 seconds should be enough time for any small solder joint like these.
The secret, of course, is the same as the route to Carnegie Hall: Practice, practice, practice. :-)
Cheers! Rich
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Ross Herbert
contacts
take
being
solder
Rich, I totally agree with your conclusions re practice...... However, the OP said he was a "beginner' and thus is not likely to have yet learned the hard way how to achieve perfectly soldered joints in under
2 seconds. Even then, the wattage and/or the type of soldering iron he has will be relevant and we don't know what he has available. For example, if he uses a 60W non temp controlled iron the plastic will allow even less than 2 seconds of heating before the pin sags.
During my professional tech days we always used high quality switches by C&K (circa 1970 - 80's) and the contacts on these would allow quite long periods of heating without any damage or plastic melting. They could be soldered and unsoldered many times by a technician properly trained in soldering techniques. When I had to buy some small switches a few years back - they looked to be good quality, and appeared identical in style to the old C&K's, I discovered very quickly that even with my experience it was easy to get the pins to sag with only quite short periods of heat application. They were certainly designed for one attempt only and it would be impossible to unsolder and re-use these switches.
That is what I was referring to with the RS relay and what the OP had to be aware of.
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