Friday, January 23, 2015

HOWTO: Create your own PCB Island Pad cutter tool

Greetings. After Bill Meara posted my Mighty Mite design on his SolderSmoke blog, a lot of folks found there way to my Transistor Islands post. I think it would be helpful for others if I shared a bit more about how I make my island cutters. First, I must state that in no way is this an original design. I owe great homage to all the homebrewers who have contributed there own techniques of making island pads on copper clad. It took me trying a lot of different ways of rapid prototyping to find that I enjoyed this method the most. I should mention that when I am building a final (non-experimental/prototype) version of a circuit, I make the layout different than the island pad method. I will make a post about that method at a later date.

Always wear safety glasses and a respirator mask when cutting into copper clad material. The resultant powder can be very dangerous.

Here is my "method":

 I make them from Wood Carving Set from a Hobby Store.

I use an off-brand "dremel" type rotary tool. It is much less powerful than my Dremel brand rotary tool which I find actually helps as it gives me more control when making the blades.

Here is a very crude template for the general shape I cut the wood carving blades into for use as an island pad cutter. If you are going to fit them in metal utility knife handles, the bottom / base of the blade must be shortened to fit the metal handle (at least in my case).

                                             I've made some by cutting the Wood Carving blade while it is still in its original wooden handle.

 I have also made them by removing the wood carving blade from the wooden handle and using a Panavise to hold the blade while I cut it to the desired shape.

 Remove the blade from an X-acto type utility knife. Reduce the size of the bottom/base of the island cutter blade that you make so that it will fit snuggly in the utility knife's metal handle. It makes for a sturdy and attractive island cutter

 I find that using one of these types of files, which I believe are used for sharpening chainsaw blades, makes it easy to keep your Island Cutter nice and sharp after regular use.

 Here we see three island cutters that I made from the wood carving set. One is in the original wooden handle while the other two are in metal utility knife handles. there is an example island to the left.

 Here I begin the process of creating an island by press firmly down on the copper clad. I put a bit more pressure on the side of the blade that will act as the pivot
 Rotate the tool around the pivot, dragging the other side of the blade across the surface of the copper, applying enough pressure to carve just enough of the surface off and expose the FR4 (or whatever your preferred board type) layer below.

 Rotate clockwise, rotate counter clockwise, dig into that clad and isolate your pad! This is fun!!

Within a few seconds, with a few twists of your mighty CW fist, you wil have a beautiful isolated island home for your precious RF components!

A scouring pad helps remove the copper debris from the carving process.

The most important part of the procedure, check continuity, make sure your island isn't a peninsula!

There you have it, folks. I hope that by illustrating it this way, anyone who didn't have a clear understanding of how to make islands on copper clad, will have such an understanding now. As I said in the beginning, I make no claims to originality. This is just my method. There are many others. I simply used what I had on hand to make this, purchasing nothing to build the island cutters, in the true spirit of homebrewing. Lets hear about how you make islands! Please share below. Maybe you are trying to make an island cutter similar to mine but having trouble, please feel free to ask questions or give feedback below or email me.

Thank you for your time, best wishes, keep your iron hot and stay fluxy!