I’m gearing up to start working with SMD’s. Planning on using a mixture of toner transfer boards and house boards - IC’s will be SOIP type. Soldering will be a mix of hand soldering and toaster oven reflow with solder paste.
Should I start with larger 1206 packages for resistors and caps and work my way down to smaller sizes?
Chances are that I won’t have a stencil for the home etched boards - and was planning on using a fine tip syringe to apply the paste.
Advice?
I started with 1206 but quickly jumped down to 0603 - still easy to solder by hand without magnification, and the most bang for the buck in reducing the size of your PCBs. Might as well just start with 0603 so you can build up a supply of the common values.
Using solder paste in a syringe definitely helps with 0603 and fine pitch IC, it has a pretty long shelf life, even if you forget to put it back in the fridge.
I suggest the 0603 parts. TQFP and the like is also easy to solder.
You’ll soon find you can hand solder (without paste even) 0603 parts faster than some through hole parts.
You will need small tweezers, and solder wick. For caps and resistors, I suggest putting solder onto one pad of the footprint, then grab the part and reflow it back into the pad with the iron only, while pushing it flat to the board. Come back and do the other pad. Having a flat finish (such as immersion silver) helps - HASL can be a bit bumpy at times.
I’m still using 1206s and 805s. The reason for those is that you can run a trace through the gap between the pads. even 12 mil. That makes layout a lot easier. especially if you make your own boards. It’s possible with 603s but it’s really really tight.
However, I agree that 1206s are monstrously big!
By the way, I found this really good page on SMT notes. There is a ton of good info in it. http://www.ibselectronics.com/pdf/pa/wa … _notes.pdf
I would go straight to 0603, very simple to solder with some good tweezers.
My hand soldering method is simple, add a small amount of solder to one side pad of every 0603 on the board.
Hold the part with tweezers, heat up the solder on one side, then put the part onto the board, let the solder cool.
Do all of these parts like this, and then go back and add solder to the other side.
I did start out with 0805’s, but there is hardly any difference in size when compared to a 0603.
1206 I only use for big power rated resistors, and big tantalum caps.
0402 is possible by hand, but its not as fun as 0603 is, and not much of a space gain unless you are designing a VERY dense board.
Side note, but these are good tweezers for SMD work. Very solid.
Good tip. I have a whole heap is DX tweezers, I like these ones usually:TheDirty:
Side note, but these are good tweezers for SMD work. Very solid.
http://www.dealextreme.com/details.dx/sku.7042
But for the price, you might we well get one of each type, that’s what I did 
don’t forget to look up toaster oven reflow 
i would mostly echo most of the things folks here have said – i started with 0805, and I find 0604 to be a really good size. 0402 is pretty tiny, and really good for high density situations, but probably not for general use if you don’t need them.
I also have extensively used the paste-then-hand-solder method, but I’ve been using toaster oven reflow for a few boards recently and it’s worked out very well. I’m not sure if it works so well for tight-pitched SMD parts (like 0.4-0.5mm) unless you have a solder paste stencil, as there usually isn’t room for the solder mask between pins on the boards I’ve had made with such tight pitches – so imperfect paste application can lead to lots of bridges. (This might be a bit of a problem with my technique – I’m perfectly happy to learn an easy, no-stencil method for toaster ovening 200 pin tight pitch parts. 
)
one other quick thing to node, that you’ve likely read before – removing SMD parts is very difficult with a conventional iron, but very easy with a hot air rework station. there are some inexpensive hot air stations available out there, like the one’s sparkfun sells, and if you have the extra cash they are fantastic to have around for SMD work.
best of luck!
Thanks guys!
After looking at the foot pad of 1206 - you guys are right - they are rather large for a SMD. I think I’ll pick up a kit of 0603’s and start some practice runs.
The more I think about it, it seem that the smaller the part, the more it will “self-center” during re-flow - sounds about right?
Thanks for the advice.
uh, not my experience - the 1206 floats rather like a stately ship on a sea of solder. very nicely centered.
I generally like 0805 because I can route 2 traces between the pads, which reduces my needs for vias.
On the other hand, I like 0603 for bypass caps because Vcc and Gnd are usually next to each other on micros and it makes routing nearby pins easier (I don’t have to route around a big passive that needs to be close to the pins).
I have 0805 resistors and 0603 caps (when available). The only reason I have 0805 resistors is because I started with them, and I have so many now, I don’t want to have to worry about whether the resistor I’m adding in Eagle is an 0805 or a 0603. …but I like the trace between pads argument. I’ll use that as my own.
For larger electrolytes I use the nichicon metal canister types.
I have a bunch as well. I don't like those as much; I find the tips to be a little 'bendy'. I like how solid the ones I linked are. Sometimes I use the others though because they open wider and you can grab whole chips or larger items.gussy:
Good tip. I have a whole heap is DX tweezers, I like these ones usually:TheDirty:
Side note, but these are good tweezers for SMD work. Very solid.http://www.dealextreme.com/details.dx/sku.7042
But for the price, you might we well get one of each type, that’s what I did
If you have never worked with SMT parts before, I suggest starting with 0805 size parts. They are small enough to squeeze a bunch in a small space, yet big enough to hand solder without much problem.
In fact, I still primarily use 0805 size when I can because they are so easy to work with and my designs typically don’t require anything smaller.
I started with 0805 and didn’t have any problems with them. 1206 parts are getting hard to find here in the UK, not many people use them.
Leon
0603 is the smallest I use, but I don’t hand solder anything that small. If the 0805 part is available, it’s what I prefer. Also, if you don’t have the best eyesight, 0805 is still fairly easy to see without a magnifier.