soldering technique

If you apply heat and solder to the wire, solder will flow along the wire and onto the pin, if it's in contact.

Soldamop wick is handy if you need to remove solder.

Hello, Andrew! You wrote on Wed, 30 Aug 2006 22:09:59 +0100:

??>> Quick newbie soldering question. I need to solder some wires to pins ??>> on an SOIC package. I've never soldered something with this small of ??>> pin spacing. Is there a trick for first tacking down the wire to the ??>> pin before you solder so that it stays in place? Thanks for any tips ??>>

??>> Kev

Clearly the wire needs to be a slightly smaller dia than the pins and single core, I find it best to "tin" the wire and the pin first and then holding the wire against the pin just a quick touch with the iron and they are joined. Of course the mechanical strength of a solder join like this is a bit questionable so it's advisable to tack the wires down to the board as well, with silicone or hot melt.

With best regards, 3T39. E-mail: snipped-for-privacy@hotmail.com

upside down on bluetak

martin

I used to do it all the time when SMD parts first came out. Invert the chip and anchor it to a piece of blank PCB with a dob of hot-melt glue. Then tin the wire and the SMD leg, touch the two together, then reflow it with just a touch of the iron. Takes longer to write than do!

Barry Lennox

One slight thing to remember though. When the chip has been placed on the board upside down, in BluTack or whatever, the pin numbering is back to front. Oh how many times have I caught myself out on that one ... !!

Arfa

Yep, that got me once or twice. But then the first thing I did was to use a short heavy wire to connect the ground (pin 7 or whatever) to the PCB. That served as a reminder of what was where. It also helped hold the chip in place, as the hot-melt can loosen as soldering proceeds.

On Wed, 30 Aug 2006 22:49:02 +0100, "3T39" Gave us:

Not if one follows the pre-tin operation with a drop of flux (microdrop) on the wire or pin. Then, the reflow operation is pristine. Crisp and clean, no caffeine. :-]

On Wed, 30 Aug 2006 22:49:02 +0100, "3T39" Gave us:

Best to use teflon "hook-up wire" and Loctite's "tack-pack" cyano-acrylate adhesives to pin the wire(s) down to whatever substrate is involved.

On Thu, 31 Aug 2006 10:23:02 +1200, Barry Lennox Gave us:

Flux is your friend.

On Thu, 31 Aug 2006 12:43:45 +1200, Barry Lennox Gave us:

If you are adding that much heat to a chip while soldering on simple hook up wires, your are already outside the box from a proto builder POV. Very bad technique to say the least.

Blu-tack the IC to the bench. Tin the lead and the end of the wire. Hold the wire in place with tweezers, dab, steady hands, job done.

And stay sober the night before.

Paul Burke

You can also get some handy tips from Wes Hayward's pages at

Barry Lennox

It might help if you bend alternate pins up and down.

I'd just make a PCB - much easier

Leon

3M (i think) had some self-adhesive pads with SMD layouts taken out to the nomal 0.1" spacing and power strips e.t.c. It worked surprisingly well with a piece of plain pcb as the substrate and ground plane. Now it's so easy to run a PCB that I do not bother with anything else for prototyping.