I haven’t designed a PCB since I was at school, using an Acorn Archimedes computer and their version of paintbrush, so KiCad has been an interesting and enjoyable learning curve.
I’m using purely THT components, because it will be manually soldered, but I notice all the tracks are by default showing up on the ‘F-Cu’ layer. I prefer this idea, because the tracks can be closer to the pins without the risk of a short-circuit caused by soldering, but I am just curious if by default the holes for the THT components connect the two layers?
If not, can I force it to? Or do I need to put all the tracks on the B-Cu layer?
By default through holes are on both layers, but if you order a single sided PCB, you would only submit the F.Cu gerber, meaning they would be single sided
There is usually no cost difference unless making the PCB yourself, and plated holes for components are much harder to tear off.
You can place the track on either layer, the goal of a PCB is to connect everything up within your constraints, there are no real rules about this stuff, as if the pcb has a “solder mask”, you do not really have to worry about shorts as much, just keep the spacing wide so its easy for you if your not as confident in soldering
You should not assume that manually soldering SMD packages is a big problem. SO packages with raster 1,27mm are (in my opinion) even simpler to manual solder then THT provided you have a soldering iron with a relatively sharp tip and thin (0,5mm) solder tin. You solder first two pins on opposite corners to position the package (can be improved many times) and then when you are prowd of positioning the rest. Also SMD resistors/ capacitors down to 0603 package are simple to solder provided you have a sharp tweezers. It is much simpler then soldering THT resistors and capacitors.
Around 1990 we used to design our products using THT ICs (at top PCB side) and SMD resistors/capacitors (at bottom PCB side). Consider also such solution.
I’ve always had more trouble with THT then with SMT, especially for home brew stuff.
Drilling all those holes in the PCB. cutting all those leads of resistors transistors, and other components. Turning the PCB to solder on the other side, working with mirror image of IC’s while working on the under side. Components falling out when you turn the PCB.
All these are history when you use SMT.
With SMT you have to work more precise, partly because components are smaller, but also because you have both components and solder on the same side.
You do need flux and good tweezers to work comfortably with SMT. There are plenty of tutorials on youtube. For a beginner I’d recommend 0805 size for resistors and capacitors. These also fit on Vero board. Bigger (such as 1206) is not a real benefit, and 0603 is still doable, but a bit finicky to handle because stuff gets pretty small. Smaller then 0603 is not recommended without quite some experience and a decent stereo microscope.
That’s very interesting to hear. In my late thirties, it’s nearly half a lifetime since I did electronics at school, and about as long since I did any real soldering. I’ve invested in a decent soldering iron to give me a fighting chance, but the plan was to make it as simple as possible.
Because I’ve not got much experience in soldering, I’d basically ruled out SMT, but it looks like it might be worth considering. I get what you are saying about components falling out when you turn it over though.
FYI I second what @paulvdh said. For all my personal projects I use 0603 passives for hand soldering and have very few issues. I use a microscope at work for hand-soldering 0402 and 0201. 0201 is kind of difficult but 0402 I find not so bad.
It’s important to have a clean soldering iron and good quality solder. I prefer a small chisel tip over a fine point – you would think that the fine point is better for smaller things, but actually I find it harder because you can’t get the heat into the part fast enough.
I like something in the range 1-1.5mm wide. It’s small enough to do 0402 without too much trouble (as long as your 0402s aren’t right next to each other) but large enough to get heat into larger parts like connectors. I use that 90% of the time and only rarely do I have to use a smaller conical.
I will note that having a soldering iron with smaller handpiece can be very helpful for better control. The most important thing is the distance from where you grip and where the tip is. Most beginners get something like the Hakko FX-888 or similar, and these stations have handpieces where the tip is fairly far away. This makes soldering small parts a lot more tricky (try writing with a pen you are holding far away from the tip…) Getting a station with a “micro” handpiece makes soldering small SMT parts a lot easier. In my opinion it matters more than having a microscope.