How to globally put component pads on B.Cu back copper only?
I am making some homemade/homebrew PCB that I only want the component pads on the back layer. The component pads do not connect to anything on the front layer so they are not needed and look messy.
It is a 2 layer board but I only use the front layer for a few ‘jumper’ tracks but mostly labels etc.
Put the pads on the front layer. When the board is physically ready, flip it in your hands. Voila, the the back becomes the front and vice versa!
If you want more serious answer, you should tell what’s wrong with the less serious.
While I am all for brevity, unfortunately you did not read my message properly.
“I am making some homemade/homebrew PCB that I only want the component pads on the back layer”’
At the moment all component footprints have pads on the front and back layers. As I previously said, I just what THOSE pads JUST on the back layer.
I am able to do it one pad at a time but that is very time consuming for all of the components.
At the moment I select a pad of the component, press E, Change the Copper drop down list to B.Cu. The pad turns green and jobs a goods done. That is just long winded for every single component pad.
Create your own component library. Do the work only once per component type, not for each individual component on the board. Presumably you don’t have so many different footprints that it would be too much work, and you can reuse them later if you make another board.
Yes that was the only thing I came up with too.
Seems a bit silly really that you have to jump through hoops to do such a basic thing but I guess it is what it is.
Thanks for taking the time to answer eelik 
All modern manufacturing techniques are based on plated through hole technology. Your specific workaround (using the second layer as a jumper layer in combination with non plated trough hole) is not really needed by a vast majority of users. So if somebody makes a feature request like the one you suggest it will get very low priority as implementing nearly anything else will have a much bigger impact (be of use to a much larger number of users).
Why does it matter if the pads are also on the front layer, if you’re not actually using the front layer for the PCB?
Nothing major. It looks messy/odd with a load of copper pads not connected to anything around component holes on the top side. It also means I have to tin that side/ solder it to stop the copper degrading.
Additionally it takes up space around the component on the top side where I may want to put a tighter ‘jumper’ track. Jumper tracks I have at 0.5mm so the alignment is a little more forgiving and easier to do as the process goes through a heated laminator.
You say that you will be making these boards yourself. When exporting the board to your manufacturing process, exclude the top layer. Just because a layer exists in KiCad, doesn’t mean that you have to use it as artwork on the board. There are several layers where there is no intention to physically manifest that layer on the board.
I’m not sure what you mean by the process going through a laminator. You haven’t explained your process in sufficient detail. But, having the pads around the component pins on the top of the board I would think would help enforce clearances to keep your jumpers from shorting against the component pins. Even if you are using insulated wire for jumpers, if one of those wires is against a pin, not only do you risk melting through the insulation when the component pin is heated up during the soldering process, but vibration will cause the wire to rub against the pin potentially wearing through the insulation over time.
I use the heat transfer process which involves laser printing onto a glossy sheet. These sheets are cut out and taped to a copper clad board then put through a modified heavy duty laminator to transfer the print. The paper is then washed off leaving the toner. The board is then put in developer solution in the usual way.
I never really thought about it before but I suppose I could put my jumper tracks on a different layer, not the top one then turn the top layer off as you say and just use my own layer as top layer.
Yes that will indeed be exactly what I am after!
Thank you SembazuruCDE
P.S. Your point about clearance is also very valid. I generally leave plenty though.
I think he doesn’t use wires but tracks at top. As home-made thermo-transfer has only not plated holes he will have bigger clearance if there will be no pads at top. Limited accuracy of technology is the reason he wonts to not have pads at top (you make the envelope from printed top and bottom and insert PCB into it and then go with that all through modified laminator).
I don’t know why but it looks also that all of these top layer tracks ends at vias and not pads.
I’m not sure if at that layer you will not have the pads also.
May be you can design the PCB as normal - 2 layer (with pads at top) but before printing top layer just delete elements. It can be simpler then modifying all pads ar footprints.
Or just leave the pads in there. They do not hurt and if soldered might improve the longevity of the pcb.
Also, if the top layer is already present why not use it to its fullest? For example to get a proper ground plane.
(I kind of assumed that the top layer is only an imaginary one and that it is only used to document where jumper wires are placed from the original description)
I think they hurt.
For example DIP-14. Pads 1.6mm with hole 0.8mm.
When you have pads you have 0,94mm space and when you have no pads you have 1,74mm space.
From original description:
I understand - not wires but tracks.
Assume technology is track=0.5mm, clearance = 0.5mm - you need 1.5mm space to go with track.
With pads not possible. Without - no problem.
Removing F.Cu from all TH pads should be easy with a bit of python scripting.
Indeed you have it pretty much spot on.
The only reason I have some jumper tracks is If I can keep those down to just half a dozen, I will just use wires and not bother with with top layer. Otherwise there will be a top layer with the equivalent to a silk screen showing board connections / pins assignments (not component designations) in copper and the jumper tracks.
The reason I prefer to use jumper tracks on a prototype design like this is there is no through hole plating on the homebrew board. So, having a pad on the top of the board on a component would need soldering on the top and the bottom pads. This is not very practical or possible in a lot of cases even with long component pads so it is easier to keep all the component pads on the bottom layer and use the jumper tracks in a more accessible place where both sides of the track can be soldered.
I know this seems like a faff but it is still a quick turn around for me to get a few parts of my breadboard design onto homespun PCB rather than waiting a few weeks and keep costing money each time that I do not have.
The final designs will be a production PCB of course.
My apologies, I had also missed that your “jumpers” are actually tracks of copper etched out of the top side.
If this is a common technique that you use, you may want to start making your own versions of the footprints. This will require some significant work to start, but progressively less work the larger your own library of footprints grow. My suggestion is to modify the footprints that you use from the standard library into versions of the footprints with only B.Cu selected for the pads. If you aren’t sure of how to do this, check out this FAQ:
If you need more of a primer and some good suggestions on how to organize your own set of libraries, check out this FAQ:
Edit: Images in the FAQ are working again.
@castingflame You have generated a nonsensical question.
My advice is: Do NOT do this.;Front or Back for a board with traces on one side only is effectively a 1 layer board.
Chose a side, Back(B.Cu) is recommended, and disable the other copper layer in the Board Setup/Layers Menu.
You misunderstood the intent. @castingflame makes two layer boards but wants to have more freedom on the top side. (Removing pads allows more space for traces that would otherwise not fit. They also want to have the top side as empty as possible.)
And most importantly: This is not a nonsensical question! Nearly every user concern is valid. (Some feature requests might be of negligible priority but they are still valid requests. Even requests not fitting with the general plan of kicad are valid in their own way. They show corner cases of what will be possible.)
SembazuruCDE
Re your suggestions about new footprints.
Yes, yesterday I did just that. I created a new library for these and saved edited versions (ie B.Cu pads only) of existing footprints and saved them there. It worked perfectly and I thank you for your help. It is much appreciated.
Sprig
I understand that most users no not use homemade PCBs anymore but this does not make this an irrelevant question. A lot of people still make home made boards. The only way to get a plated through hole that is accessible to solder properly is to make a vias that are connected with a pin that is soldered on both sides. I have already explained this above.
Also use the top layer for the jumper tracks (that can be soldered top and bottom) and I use it for labels of pins where needed as I have no silk screen. I have also explained this above.
so in answer to your quote of me…
“It is a 2 layer board but I only use the front layer…” … for Jumper tracks and labels.
“The component pads do not connect to anything on the front layer” because there is no through hole plating so the component have to act as the connection to both layers. This is not always possible to solder the component to the top layer when the component is fitted to it even with long pads! That is why I make those connections Off pin in the form of top layer jumper tracks where the top and bottom layers can can accessed and soldered. I also use the top layer like a silk screen to show pin values/connections as I have no silk screen.
Yes a small percentage of people make home made PCBs now but I am making valid boards that work well and can be made within a day. So this IS a valid question.
The question is resolved now so I will mark it so. Thanks all for your Input.