Improving PCB enclosure building

I was recently inspired by the fantastic website of K7QO to try to do something to improve my PCB enclosure building, both from an efficiency perspective as well as from a neatness point of view.

I built a fixture in accordance with Chuck's directions on building enclosures and it turned out very well. Last night I was able to test solder together two sides using a piece of 24AWG insulated wire to ensure that the angle was 90 degrees once the solder dried (see pics below). I used a 30W Weller iron.  I found that the technique worked better by having the vertical piece of PCB mating directly with the bottom of the fixture and in front of the 24AWG wire.

Enclosure Fixture as per K7QO. The walls are a bit high. A lot of time was spent ensuring that the corner consisted of all 90 degree angles.

Much as I would love to own a shear I found that I could accurately cut PCB's to exact size using my table saw. More on that later when I get to build a prototype enclosure as the next step.

Thanks to Chuck for sharing his extensive knowledge with us.

A piece of insulated 24AWG wire is used to compensate for the solder shrinkage

Clamps are  used to hold the pieces in place

The 'shrinkage compensating angle' can be clearly seen

Completed prototype effort. In fact the thinner black wire resulted in a better right angle finish 

Making PC boards the size you need

My shack here in South Africa is equipped only with hand tools and a power drill. Since I have a lot of PC board on hand it makes sense for me to fashion my enclosures from PC board. To make the pieces fit neatly together, I have spent large amounts of time filing the boards into shape. I find that the aviation 'tin snips' I use to cut the PC board work well, but it is very difficult to cut an accurate and straight edge.

Here is a method that works for me. I use a jig consisting of a trimmed piece of particle board about 1ft X 8 inches in size and about 3/4th inch thick. Along the straight edge I secured a piece of aluminum strip flush with the particle board top surface. This strip is screwed on with countersunk screws. At right angles to the straight edge and at one end of the board I have drawn a straight line to act as a guide to ensure the pieces are shaped with the edges parallel and at right angles to each other.

Procedure

1. Mark out the PC board and cut it closely to shape using the tin snips. 
2. Select one of the edges as a straight/master edge upon which all measurements and right angles shall be based. 
3. Line this edge up with the aluminum strip edge, ensuring that minimum wastage occurs but at the same time leave a small amount protruding to allow a good trim.
4. Press down firmly on the PC board with one hand to ensure that it does not move during sanding.
5. Sand off the excess using the circular sanding tool fixed in the drill chuck, operating at high speed. (see pictures below). Don't over do it otherwise the aluminum strip will be sanded also. Keep the drill vertical to the jig.
6. Smooth the edge further using a file and then fine sandpaper.
7. Perform the same procedure on all edges ensuring the piece is exactly the dimensions required.
8. Now use this piece as a template for the remaining boards. The other boards will be marked slightly larger due to the marker thickness. This is all good since they can be trimmed to the required dimensions using the jig as described.

This procedure takes much of the pain and time out of filing. Arguably, making the enclosures turns out to be a bigger and tougher job than putting the electronics together hi!

Jig with aluminum edge, straight-edge, tin snips, markers, sanding tool, finishing file

Hold the board firm and do the sanding outside. PC board dust is no fun!