Amount of solder/solder paste...

[alank2]

Hi Everyone,

So I've got one of those 7351 viewers and it has the least, nominal, and most settings for pad sizes.  I've baked a few boards with success, and I used stencils with a .005 thickness from oshstencils.

One of my early failures was using a pad size that was too small and it didn't have enough paste to wick up into the part when reflowing.

My question is this - I often see pcb's on eBay where the thinnest of solder is present, you can make out all the legs of parts and they look more plated with solder than coated with solder if that makes sense.

My thought is a more is better so long as you don't get bridges, but I wanted to hear what the wisdom here at eevblog is on this.  More, less, what is the ideal?

[GreyWoolfe]

I weigh in on the less is more.  No real experience with SMD but I was taught to use just enough solder to cover the pad and wick up onto the component leg.  The larger the pad and component leg, the more solder is needed but it shouldn't form a mound.  Again, just enough to cover the pad and wick up onto the component leg.  More may be considered wasteful.  To me, you are forming an electrical connection not an unbreakable mechanical connection and that electrical connection doesn't need the solder piled on.  IIRC, in an old Dave video, he sides on the less is more side also.  It will be interesting to see what others have to say.

[nanofrog]

Even if you don't create any bridges, you don't want to "pile it on". You want to create a fillet anywhere the component lead makes makes contact with the pad.

NASA Training Program: Student Workbook for Hand Soldering would be worth your time (.pdf), as would NASA's Workmanship Pictorial Reference (this one covers more than just soldering). 

If you like videos, Pace put up some really good ones on YouTube (don't let their age fool you, they're really good).
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