thank you so much for detail information @paulvdh.Its helpful.
Imperial size 0805 are easy for most people to hand-solder, in my experience. You can use the hand-soldering footprints in the Kicad library to make things even easier. Nearly all parts are available in 0805 size, unless you are laying out high frequency radio stuff you’re probably ok.
I’m now going to 0603 because I find they’re still fairly hand-solderable, but slightly more difficult.
You can use a mix of sizes, and use bigger sizes for some things if it makes it easier, e.g. 1206 for capacitors or led.
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I find 0402 too fiddly even with a stereo microscope, so 0603 and 0.4mm pitch pqfp is my limit
0603 is the smallest size resistor with the value on it too
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thanks for response @MarkR.Its helpful.
I have had unsteady hands all of my life; mild “essential tremor”. I am 68. When SMT was introduced, I was intimidated by it. But nowadays I can hand solder 0603 chips routinely. One recommendation is that I like to use a relatively small 0805 footprint for my 0603 chips.This provides more room on the pad for the soldering iron tip.
0402’s? No. I have done them, but half the time I lose the chip in the drop of solder on the end of the soldering iron.
In my opinion, SMT is often easier than thru hole because you do not need to worry about holes filling with solder. I think it is much easier to change values of an 0603 chip on the board than to change values of a 0.25W thru hole resistor. So dive into it with courage. I do recommend a desolder tweezer. Two soldering irons can also work to heat both pads at the same time.
In my lab I stock 0603 and 1206 resistors but not 0805s, with a few exceptions for milliohm values. If you have a small 0805 footprint, it might be easier to solder an 0603 chip onto those pads than an 0805.
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I would say once you get comfortable with hot air, you start looking at your PCB’s with a twisted sense of size, everything just ends up looking stupidly large, and you may get into a habit of packing things into smaller and smaller sizes
Makes for some fun, but annoying when you then realize the PCB needs to be 5x bigger for the mounting holes
E.g. 0201 10nF capacitors just so perfectly fit across 0.5mm QFP package pins, but it is not an easy task to place them or rework them if you ignore the courtyards, if you follow them, in most cases things will be easy to assemble with sharp tweezers,
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That usually requires a paste stencil, too. I have experience only with steel stencils, but I know it can be frustrating to learn to use it. 0402 can be soldered with an iron and the stencil isn’t needed. 0201 may barely be possible with an iron, too, but only with a good microscope (and good component placement as you said), and I don’t recommend it. Additionally it may be surprising that going to 0201 from 0402 saves relatively little space. With those sizes the tracks and especially vias take quite much of the space in the board and 0201 is worth it only if you can go for really thin tracks and smaller than standard vias – and actually really need all the space you can get.
As for the original question – why not just go after their recommendation. I think the opinions in this thread confirm that suggestion. The question of 0402 vs. 0201 is interesting in its own right, but not relevant for that.
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Not really, just a lot of stubbornness,
Pre-tin pads, add a dot of gel flux and poke stuff when it doesn’t self align correctly,
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I used to use for it one 110W trafo soldering iron and one soldering iron with sharp tip. When I have the element (typically 0603) taken out of PCB and between then I switch off the trafo soldering iron and the element stays at it and it is cold at once. Then I take tweezers to my second hand and take the element off the iron (by switching it on for a second).
In past (when I didn’t had those iron with sharp tip) I have also done special shaped wires used with trafo iron to heat both ends of elements like 0603 (I had also special shapes (with one leg bigger) for SOT23 and SOT323).
We switched from TH elements to 1206 and than to 0805 and then to 0603 and we finished that process in previous century. Now we use mainly 0603 and some 0402 (mainly 100n blocking capaciotors to place them close to IC pin pairs (VCC+GND) and to not block tracks from next pads.
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Many KiCad libraries have alternate hand solder footprints with bigger pads that allow the iron to touch the pad
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But that way I don’t get to re-invent the wheel! 
Seriously I have dimensions that I have used previously with other pcb layout software, and it is not a big deal to make my own footprints for these SMT parts. I only need to make each one once. Another footprint will fit anything from 0603 up to 1210 for hand soldering.
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I would definitely recommend using 0603 (imperial size) rather than 0805. I consider 0603 a good general purpose size for at lot of things, and yet they are still easy to handle with manual soldering, that be iron or hot air. Just my comments, although I know I did not add much more information here to all the other replies
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It also seems to be the case that it is easier to get 0603 compared to 0805. Was especially noticable during the MLCC crisis.
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Yes, 0805 and larger is verging on obsolete/specialist.
The snag with the smaller parts in some of my projects is low voltage rating even when the power rating is no problem. Most volume consumer products are built with 0402 or 0603
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For me, 0603 is comfortable to hand-solder and all my designs use 0603 parts (if possible).
I generally use paste and a reflow oven most of the time but for prototypes I’ll often hand-solder first ( unless there BGA parts involved).
I use Kester 959T liquid flux in a squeeze bottle with a needle for SMD work. Can’t stress how good this stuff is for hand-soldering or touching up after a bad reflow. Also, high-quality solder is extremely important. I use Chip Quik SMD291AX paste for reflow and Kester 24-6337-8806 for hand soldering. Kester solder is the best you can buy in my opinion. I also have a Hakko 915F solder station with a collection of different tips. I find for soldering 0603 caps and resistors a chisel tip works best and for QFP and SOIC parts a bent conical (or flat) tip with a reservoir works best.
I’ve been able to successfully hand-solder QFN but I don’t recommend it.
With 0402 I’ve hand-soldered a few times but avoid caffeine because hand-shaking can be disastrous. 0402 parts often get stuck to the iron tip or go flying across the room never to be found again. Definitely need a 10x microscope or you can get +7 reading glasses on eBay which work well.
0805 looks enormous to me now and I rarely use this size in my work unless it’s a large value capacitor
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What I have seen is that 0603 and smaller is still quite common for “everyday values” and 1206 / 1210 are common for parts that are currently impossible to cram into an 0603 (very large capacitors, high voltage ratings, high power resistors, etc). 0805 I guess doesn’t offer enough of a useful middle ground
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they suggest me to use 0804 SMD Packages.
Here are I think important points to consider before applying a one size fits all rule (which usually is a bad idea):
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It all depends on what your approach to soldering these SMD components is: I use DIP only for quick prototyping, but found 0603 easier to solder than bigger ones like 0805,1206 when using solder paste with my SMD rework station because you can cover more components with your hot air in a given area. Now when using a soldering iron, of course 0805 or even 1206 can be a better choice…
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You should be careful not to use always your preferred size (i.e. 0603) but instead, always check the datasheet of your component during your design phase, as many smaller components have different characteristics.
The most common mistake being using a small resistor ref. that is 1/10W when your design needs at least 1/8W …
Same for capacitors, always check the max voltage of your particular package (should be at least twice what your design is supposed to use by default).
- Make sure you use hand soldering special footprints when you use a soldering iron
SMD soldering is both fun and efficient with a bit of practice, good luck!
-Fab
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