soldering surface mount components
Jul 2, 2003 at 2:48 AM Post #2 of 8

KTpG

100+ Head-Fier
Joined
Jan 17, 2003
Posts
436
Likes
10
Don't drink caffeine
Use small soldering iron tip (and lower wattage iron to control how easily the solder will flow)
Use small solder
Steady your shaking hands (my hands shake... especially when I am trying to be careful....)
 
Jul 2, 2003 at 3:02 AM Post #3 of 8

stereth

500+ Head-Fier
Joined
Mar 13, 2003
Posts
958
Likes
10
I had to solder some surface mount parts, including 50-mil chips, for work last week. Small solder is crucial for chips. Small soldering iron tips are also very nice - especially asymetrical ones that have a tip over to one side. All kinds of surfaces to use.

Tin at least one pad before you put the part on the board. With resistors, put a mound of solder on one pad, put the piece in position, reheat the solder, and use a toothpick to keep it in place. With surface mount chips, tin two corner pads, then reheat one at a time as you press the chip down. Even with one or two pins down, with small legs, you can still move the chip where you want. To check the chip afterwards: test all adjacent pins for continuity (solder bridges), then each pin to the next part it connects to.

And if you have surface mount transistors or LEDs...good luck. The toothpick works wonders because even a tiny magnetic field on a pair of needlenose pliers can pull a 1206 resistor out of place if it's not soldered down.
 
Jul 2, 2003 at 2:43 PM Post #4 of 8

BPRJam

100+ Head-Fier
Joined
May 22, 2003
Posts
259
Likes
10
Actually, I find it useful to flux the pads on the PCB before I solder the chip on. The flux serves 2 purposes. 1) It is a little sticky so that it keeps the chip in place, and 2) It allows the solder to flow onto the pad better, getting a more accurate solder in a shorter amount of time.

If you choose to use this method, though, make sure you flux only the pads, and not the space in between the pads. I use a toothpick to selectively apply the flux.

Good luck!

BPRJam
 
Jul 2, 2003 at 2:54 PM Post #5 of 8

fiddler

Headphoneus Supremus
Joined
Jun 24, 2001
Posts
1,930
Likes
30
Quote:

Don't drink caffeine


Pffffft, what nonsense.
tongue.gif
biggrin.gif
(BTW this new big grin irritates me. bring back the old grin.)
 
Jul 2, 2003 at 4:36 PM Post #6 of 8

jamont

500+ Head-Fier
Joined
Nov 10, 2002
Posts
673
Likes
10
I recall seeing a suggestion (forget where) that if the board had been reflowed, all you need to do is flux the pads, put the chip in place and heat the pins. Has anyone tried this?
 
Jul 2, 2003 at 5:31 PM Post #7 of 8

maczrool

100+ Head-Fier
Joined
Aug 1, 2002
Posts
163
Likes
10
Quote:

Originally posted by jamont
I recall seeing a suggestion (forget where) that if the board had been reflowed, all you need to do is flux the pads, put the chip in place and heat the pins. Has anyone tried this?


Yes, I have tried it, but it didn't seem to produce a satisfactory joint. There doesn't seem to be enough residual solder.

You can always have a custom stencil made ($$$) for your board and print solder paste on for reflow with the parts in place.

Stu
 
Jul 2, 2003 at 5:33 PM Post #8 of 8

kheldar

100+ Head-Fier
Joined
Jun 18, 2002
Posts
156
Likes
0
I have done some minor stuff, for IC's i had a peice of safety pin held in an exacto knife handle, bent at the end, with a bit of tape, it was small so as not to obscure my view... works, but takes time...
 

Users who are viewing this thread

Top