Monday, March 25, 2013

Final Trimming Of The Left Landing Light Lens

Since Mother Nature has not received the note yet regarding calendar Spring, the borrowed shop heaters were blazing away, yet again, thwarting off the cold in the shop. My original plan was to wait until warmer weather to finish trimming the Plexiglass landing light lens.  However, because of the way it fits and is installed, thought it best to finalize trimming the lens to final size prior to installing the left wing’s outboard top skin.

The plans instruct the builder to mark the front of the lens along the left and right edges of the opening cut into the W-1203L wing skin. The lens is then to be cut a 1/4" wider on both sides. I elected to just place blue painters tape on the inside of the lens and then transferred the measurements from the marks on the front of the lens to the backside of the lens so I could run the lens through the band saw.
                 Inside of lens marked with red ink so it can be “rolled” through the band saw to cut off the excess
                 material on the left and right sides … leaving the required 1/4" extra on each side of the lens.

I cheated and got away with cutting the lens in the cold shop by holding the lens in front of one of the heaters to warm it up prior to running it through the band saw. The lens was warmed up once again prior to making the second cut. Not sure if all that was necessary because I do have a fine toothed saw blade on the band saw but thought it wouldn’t hurt to stack the deck in my favor. The band saw made quick, easy work of cutting the lens.
                          Using the band saw to carefully cut the excess side material off the left landing light lens.

Once the landing light was cut, it was filed to the proper shape and sandpapered until all the edges were smooth with no groves or lines. (Still need to get some finer grit sand paper tomorrow to really polish the edges out nicely).
                                   Finished left landing light lens with backing strips in place ready for a trial fit.

I decided to temporarily mount the lens using screws with lots of washers so the screws won’t wear out the nutplates on the backing strips. Because I’m not totally happy with the fit, a thought that came to mind is to try heating the lens up now that it is secured in place and see if it will naturally take the shape of the opening or possibly do so with just a little pressure from the back along the edge where it does not fit perfectly. Tomorrow will try placing one of the heaters in front of the lens to get it preheated in the hopes the tension on the lens will help form it into the opening better when I apply direct heat to the problem area from the back side with a heat gun. It appears 280 degrees is the magic number to begin forming … but I just want to bend it a little, so hoping it can be accomplished at much lower temperature.
                           Left landing light lens cut to final shape and test fitted onto the W-1203L wing skin.