Gluing the Rear Windows

Time to start attaching the windows.  There are 5 windows (or “transparencies” as the plans say): one rear window on each side, one window in each door, and a windscreen (a.k.a. windshield).  The process before gluing is basically:

• Rough trim the window to the hole in the cabin top
• Keep trimming/sanding until it fits well
• Check the fit of the window in the hole, and use shims as required to make the outside of the window flush with the cabin top
• Mask the window where you don’t want glue
• Scuff up (sand) the area of the window where it will attach to the cabin top, so the glue actually sticks to it

Here I am doing some test fitting.

After that, it’s time for the gluing.  The plans recommend using something called Weld-on 10.  Several builders have experienced crazing (tiny cracks) using that, and the theory is that it’s because people use too much pressure to hold the window while the glue is curing.  Because of that, there are many different methods people use to attach the windows, but we decided to go per-plans and use the Weld-on.  To hold the window in, we drilled holes in the cabin top and used clecos and popsickle sticks to hold it in place with slight pressure.  We also thickened the Weld-on with cabosil, which also created more volume.

How were the results?  Not bad.  The window required significant shimming to make it flush with the cabin top, so that created a big area for the glue to fill.  There wasn’t quite enough, so there were some voids when the glue dried.  Nothing too major; the glue will be sufficient to hold it on.

Here’s what it looks like in place.

Here’s the biggest glue void.  You can also see I’ve filled in the gaps with epoxy.