Step 11.9, Cutting the canopy

First there was a big bubble of acrylic plastic.  The canopy, we'll call it.  It's a single piece of blown plastic as it comes from Van's factory.  It must be cut in two -- one to fit the tilt up portion of the canopy and the other, the back window.  So the trick, as any sculptor will atest, is to trim off the bits that don't look like the artwork.  An initial trim is required so that the big bubble will set over the fuselage in something close to its final position.  Once this is accomplished, more accurate measurements can be taken to effect the big cut.

So I eye-balled the initial trim and got pretty close.  Here is the canopy is back on the aircraft where I can mark the location of the big cut.  A mistake here could be very costly, somewhere north of $1500, so I am uncharacteristically careful to double check my trim lines.  

Back off of the aircraft, the line to cut is clearly visible.  All I need now is the nerve to plow into it.  

I tape across the cut as I go to try and keep the stress on the plastic at a minimum.  There have been a number of builders crack their canopies at this stage.  The actual cut is with a die grinder sporting a thin cut-off blade.  I don't have any pics of that as I was alone -- principally, out of concern for the safety of others should I make a mistake :)

And finally the back window is separate from the canopy.

A very relieved selfie

Now the edges are sanded smooth.  #120 to #200 and then down to #400 grit.

It's a bit of work, but the edges are smooth and straight.  Now back on the aircraft for additional measuring.

And some fine tuning of the forward edge and sides.

At this point the plastic work is done on the canopy.