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Half a homebrew pcb ...

2013-10-07 by arvidj01

Lets assume I have one of the ubiquitous "drilled 0.1 inch on center .08 inch wide copper" strip boards that is 8in x 8in.

I need to remove the copper between lots of the holes. Think of putting a long string of led's along the strip and therefore need to remove the copper between the two ".1 in between them" holes for the led leads.

And yes, "along the strip" is not the intended orientation if one were to put led's on this board ... they suspect that "across the strip" would be what the manufacturer originally had in mind ... but there is a constraint that suggests "along" is the preferred method.

I then began to wonder "what is the best way to create the gap in the copper between the two adjacent .1 holes?".

The initial thought was to use the Dremel and a carbide bit but the large number of cuts will make it tedious and error prone.

Another thought is to somehow mask off the board and then etch it to create the gaps between the holes. The areas that would need to be etched are very consistent and regular on the board so the thought is that consistent masking would mitigate the risks of an error.

Which brings me to "what would be the best way to mask off the board?"

Any thoughts would be appreciated.

RE: [Homebrew_PCBs] Half a homebrew pcb ...

2013-10-08 by Boman33

If you end up using the Dremel tool, do not use the carbide tips, use an abrasive cutoff disc. It works much better and is easy to control for quick operation.

From: arvidj01 Sent: Monday, October 07, 2013 18:12

Lets assume I have one of the ubiquitous "drilled 0.1 inch on center .08 inch wide copper" strip boards that is 8in x 8in.

I need to remove the copper between lots of the holes. Think of putting a long string of led's along the strip and therefore need to remove the copper between the two ".1 in between them" holes for the led leads.

And yes, "along the strip" is not the intended orientation if one were to put led's on this board ... they suspect that "across the strip" would be what the manufacturer originally had in mind ... but there is a constraint that suggests "along" is the preferred method.

I then began to wonder "what is the best way to create the gap in the copper between the two adjacent .1 holes?".

The initial thought was to use the Dremel and a carbide bit but the large number of cuts will make it tedious and error prone.

Another thought is to somehow mask off the board and then etch it to create the gaps between the holes. The areas that would need to be etched are very consistent and regular on the board so the thought is that consistent masking would mitigate the risks of an error.

Which brings me to "what would be the best way to mask off the board?"

Any thoughts would be appreciated.

Re: [Homebrew_PCBs] Half a homebrew pcb ...

2013-10-08 by Mitch Davis

Hello Boman :-)

Arvid, if you have a temperature controlled soldering iron, you may be
able to turn it up high and heat the pads off.

Mitch.

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On Tue, Oct 8, 2013 at 11:04 AM, Boman33 <boman33@...> wrote:
>
>
>
> If you end up using the Dremel tool, do not use the carbide tips, use an abrasive cutoff disc. It works much better and is easy to control for quick operation.
>
>
>
> From: arvidj01 Sent: Monday, October 07, 2013 18:12
>
> Lets assume I have one of the ubiquitous "drilled 0.1 inch on center .08 inch wide copper" strip boards that is 8in x 8in.
>
> I need to remove the copper between lots of the holes. Think of putting a long string of led's along the strip and therefore need to remove the copper between the two ".1 in between them" holes for the led leads.
>
> And yes, "along the strip" is not the intended orientation if one were to put led's on this board ... they suspect that "across the strip" would be what the manufacturer originally had in mind ... but there is a constraint that suggests "along" is the preferred method.
>
> I then began to wonder "what is the best way to create the gap in the copper between the two adjacent .1 holes?".
>
> The initial thought was to use the Dremel and a carbide bit but the large number of cuts will make it tedious and error prone.
>
> Another thought is to somehow mask off the board and then etch it to create the gaps between the holes. The areas that would need to be etched are very consistent and regular on the board so the thought is that consistent masking would mitigate the risks of an error.
>
> Which brings me to "what would be the best way to mask off the board?"
>
> Any thoughts would be appreciated.
>
>
>
>

Re: [Homebrew_PCBs] Half a homebrew pcb ...

2013-10-08 by Brian Symons

Removing sections of track or pads can be done several ways.

1. A large drill bit just in a hand held chuck to cut the track away.

2. A special Spot Face Cutter hand tool - Vero & others made them.

3. Overheating a section of track after scoring it with a knife. If you
need to remove sections, you can tack solder a wire on to act as a
handle after overheating that section enough to soften the adhesive.
Even cold, a soldered on wire, often gives enough purchase to pull a
track section up.

4. If you have resistance soldering equipment you can use that to put a
high current very low voltage which will blow the track. It can then be
fairly easilly picked off. I think that you could put a couple of
pieces of wire in a instant heat soldering gun instead of the loop of
wire used as an element & do the same thing.

5. A knife blade can be used to lift the track but that is dangerous.

6. A Dremel or other rotary tool.

Regards,
Brian.

Re: [Homebrew_PCBs] Half a homebrew pcb ...

2013-10-08 by Hamilton Elliott

Hi,
I use a CNC Sherline mill and a software package called D2nc with a 30 degree carbide point to mill the cuts between the holes. It allows me to use the holes on either side of the cut where lifting the whole strip would cause problems. If I am making a one-off board I will try to avoid making cuts between holes but if I have to, I use a scalpel to carefully cut a narrow strip in the copper.

I have sometimes used a Dremel with a fine cut off wheel but it tends to cut into the next track too.
Regards,
Hamilton

On 07/10/2013 23:12, arvidj01 wrote:

Show quoted textHide quoted text

Lets assume I have one of the ubiquitous "drilled 0.1 inch on center .08 inch wide copper" strip boards that is 8in x 8in.

I need to remove the copper between lots of the holes. Think of putting a long string of led's along the strip and therefore need to remove the copper between the two ".1 in between them" holes for the led leads.

And yes, "along the strip" is not the intended orientation if one were to put led's on this board ... they suspect that "across the strip" would be what the manufacturer originally had in mind ... but there is a constraint that suggests "along" is the preferred method.

I then began to wonder "what is the best way to create the gap in the copper between the two adjacent .1 holes?".

The initial thought was to use the Dremel and a carbide bit but the large number of cuts will make it tedious and error prone.

Another thought is to somehow mask off the board and then etch it to create the gaps between the holes. The areas that would need to be etched are very consistent and regular on the board so the thought is that consistent masking would mitigate the risks of an error.

Which brings me to "what would be the best way to mask off the board?"

Any thoughts would be appreciated.

Re: Half a homebrew pcb ...

2013-10-08 by arvidj01

Thanks for the suggestions.

To be clear about what I am trying to do.

This is what the stripboard looks like ...

http://commons.wikimedia.org/wiki/File:StripBoard.png

and the copper that I want to remove is between two of the holes.

The leads of the leds will go into two adjacent holes in the trace. If I don't cut the trace between the holes there will be an obvious short between the leads. Regretfully I can not mount the leds so they go from trace to trace the way I assume was intended by the manufacturer.

I have seen the "cutter" that is designed for these boards and regretfully they cut the copper "at the hole" rather than "between the holes".

I don't think lifting the trace is an option as I need the trace to be be attached to the board for the led leads.

Hope that helps describe what I am trying to do.

Re: [Homebrew_PCBs] Re: Half a homebrew pcb ...

2013-10-08 by Jack Schmidling

Seems like strip-board is not a good choice for this application. You
would be better off using perfboard with pads. It would take less time
to run jumpers than to re-invent strip-board.

It would also be easier to just make a PCB as long as you have the
etching capability.

js

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On 10/8/2013 9:52 AM, arvidj01 wrote:
> Thanks for the suggestions.
>
> To be clear about what I am trying to do.
>
> This is what the stripboard looks like ...
>
> http://commons.wikimedia.org/wiki/File:StripBoard.png
>
> and the copper that I want to remove is between two of the holes.
>
> The leads of the leds will go into two adjacent holes in the trace. If I
> don't cut the trace between the holes there will be an obvious short
> between the leads. Regretfully I can not mount the leds so they go from
> trace to trace the way I assume was intended by the manufacturer.
>
> I have seen the "cutter" that is designed for these boards and
> regretfully they cut the copper "at the hole" rather than "between the
> holes".
>
> I don't think lifting the trace is an option as I need the trace to be
> be attached to the board for the led leads.
>
> Hope that helps describe what I am trying to do.
>
>

--

Astronomy, Beer, Cheese, Fiber, Gems,
Nature, Radio, Sheep, Sausage, Silver

http://schmidling.com

Re: Half a homebrew pcb ...

2013-10-08 by Paul Alciatore

What I would do is mount a 1/8" drill bit (carbide?) in my drill
press, set the depth stop to allow it to cut through the copper and
not the board under it, and have at it. The drill will center on the
hole so the work is fast. Sounds like a 5 or 10 minute job.

But, of course, you do need a drill press. With a good depth stop,
not the cheap, clumsy ones that the Chinese imports come with.

Also, Vector makes a tool that is just for this purpose. It is used by hand.

http://www.digikey.com/product-detail/en/P138A/V1056-ND/7642

It will take more time with this.

RE: Half a homebrew pcb ...

2013-10-09 by <len.turnbow@...>

Brian Symons has it right in his choice #5, except that there is very little danger IMHO.

Here is how I would do that:

Hold a flat metal straightedge between holes and score across traces using a #11 hobby knife. Move the straightedge slightly and score again. Use the point of the knife to pry off the copper segments from between score marks. I've seen assemblers place engineering changes on prototypes using this method and it works a treat. Their work is prettier than mine though.

--Len

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---In homebrew_pcbs@yahoogroups.com, <palciatore@...> wrote:

What I would do is mount a 1/8" drill bit (carbide?) in my drill
press, set the depth stop to allow it to cut through the copper and
not the board under it, and have at it. The drill will center on the
hole so the work is fast. Sounds like a 5 or 10 minute job.

But, of course, you do need a drill press. With a good depth stop,
not the cheap, clumsy ones that the Chinese imports come with.

Also, Vector makes a tool that is just for this purpose. It is used by hand.

http://www.digikey.com/product-detail/en/P138A/V1056-ND/7642

It will take more time with this.

Re: [Homebrew_PCBs] Re: Half a homebrew pcb ...

2013-10-09 by Jack Schmidling

I received this via email and post it as such.

As a one time silver smith, I had a feel the solution may be in
engraving tools but just don't have any experience with one on copper.

js..........

Hi,

I am at a very limited work site, and wondered if you could please pass
this on / repost to the homebrew PCB group for me thanks.

About cutting narrow gaps in veroboard stripboard – between the holes.

I use a printmaking tool called a graver. It fits in the palm and cuts
thin groves away from copper. It is designed for thin line cuts in
copper or hardwood. Great for pcb fix ups too.

http://intaglioprintmaker.com/category/american-engraving-tools

Andrew
--

Astronomy, Beer, Cheese, Fiber, Gems,
Nature, Radio, Sheep, Sausage, Silver

http://schmidling.com

Re: Half a homebrew pcb ...

2013-10-12 by arvidj01

Thanks to everyone for the great suggestions. I appreciate the support.

The postman delivered the 11 x 19 strip board from which several 8 x 8 pieces will be cut.

I had several 4 x 6 pieces of strip board on hand when I started this project. For what ever reason the seemingly endless tracks and billions of holes in the 11 x 19 board makes the project seem much more daunting than I thought it was going to be :-}

Arvid