Remove solder mask from a track

[David_VB]

Hi,

Classic use case: I need to remove the solder mask from high power tracks to be able to add solder.
Up to now, I am achieving this by drawing filled rectangles on the solder mask layer over the tracks. But I have to repeat the process for each segment of the track.

I tried converting a track to a polygon in the hope of copy/paste it to the solder mask layer, but it does not work (Ver 8.0.1)

Is there a way, or an add-on which could allow me to easily:

• Select a track and with “u” expand the whole connection OR select a given net
• Select an action or a property “Remove solder mask from selection” ?

Any tip welcome,

Thanks

[RaptorUK]

Edit: sorry, should really have read your whole post before replying . . my bad.

[JohnRob]

Without seeing your layout I can only suggest an alternative.

Also know adding solder to a track does little to reduce I2R losses. The tin/lead/?? will conduct little current. The solder will slow down any transient overload effects.

My first thought is to create a device footprint with a rectangular pad (not sure if Kicad can handle a 1 pad device). Connect this pad-object to your trace (in schematic). Place a few of them on your track. Then solder solid copper wire to these pads, creating additional copper in parallel with your track.

[mf_ibfeew]

I tried converting a track to a polygon in the hope of copy/paste it to the solder mask layer, but it does not work (Ver 8.0.1)

Either you have discovered a bug or misused the converting function.

• on the right side appearance panel: set F.Mask as active layer
• select one or multiple tracks (start easy with one thick track segment) on F.copper
• RMB-click->context menu–>Create from selection->create polygone from selection
• conversion settings:
  • create bounding hull
  • gap & line width == 0
  • uncheck “delete source object” (otherwise your original tracks will be deleted)
  • click OK and get your polygone on the mask layer. It’s not filled at this state, so you have to change the polygone to a “filled” polygon
• LMB-click on the newly created polygon to select it → “E” for polygon properties dialog → change poygon settings to “filled”

ready. Repeat with next track, this time try multiple connected tracks to get a feeling for the conversion function.

just tested with kicad v8.0.2rc (to be sure I really recommend a working workflow)

[BlackCoffee]

I was making a Video while mf_ibeew was posting so, I won’t post my Text description, just post the Video… (did not bother with setting clearance/gap…)

[rdalek]

A additional option that may or may not work in your situation. I’m planning to make a fence charger. Some areas will have huge amounts of current but will be short in duration. To beef it up a little, I plan to add braided copper wire to those areas or traces. Solder isn’t as good a conductor as copper but may work in some edge cases where just a little more is needed. Copper braided wire tho will help a good bit since it is copper.

Make sure you get the right kind tho. Some braided copper wire is used to sleeve a wire. The kind you want is made for grounding equipment/boards and such. I think I’ve seen it as small as 2MM or so but as large as 15MM or so. May have larger too. It’s not cheap but you likely only need a small roll.

Hope that gives you some ideas.

[JohnRob]

I’ve found copper braid difficult to solder to a trace like this. I suggest you used tinned solid copper. If you don’t have tinned copper use solid copper from Romex (#14) or doorbell wire (#18) etc. You would be best to “tin” the bare copper first, for ease of soldering.

OR you can simply put a large gauge wire jumper and not worry about following a trace.

[BlackCoffee]

I recently re-posted my Tinning-Solution making approach. It will Tin Copper on PCB, Wire…etc
Here’s the link: https://www.youtube.com/watch?v=qa225K9-osg

Click the ‘more’ in description to get details…

Here’s a comment from a User, re Solder-ability after using the solution (posted in the same video but on the ‘Short’ video page

[mousey]

I have used @mf_ibfeew’s method also using zones and it works out great here is a sequence showing the top copper layer

and now I show the mask layer so everything you see in purple is masked and you will get bare copper or what ever finish you order

And finally a render of my finalized PCB with an ENIG finish

[sdrake]

Hi, I was just shown a method that looks to work. I drew a trace on the front copper then selected front mask and drew a line on
top of the trace with the same width (ver. 8) . When I view it in the 3d viewer the line shows up like there is no solder mask on it.

Is that the ame thing that you are looking for ?