I have a crimp edge that will give a nice rounded and softer edge to the aluminum, but I won't put it on until much later after I have the panel reinstalled and everything hooked up for the last time.
Once that was done I started working on figuring out exactly where the plexi was going to lay relative to the forward skin, vertically side to side, and fore and aft to determine where I would drill it and how large a gap would be appropriate between the slider frame and the windscreen.
I also had to work around the edges to determine where I would need to install small clips to pull the plexi down tight to the skins. There were some small gaps in the center (maybe 1/16"), and a couple on either side.
The sides right at the roll bar were interesting to fit. The left (pilot side) particularly really needed to be pulled down some, but I didn't want to install a rivet or add another screw at that location.
The right side was better, and I was able to just pull it down with a couple of clips installed fairly far aft along the edge.
I wanted a foolproof way to create a nice even line to use as my fairing edge. I ended up using a piece of scrap with a hole drilled in it. By inserting a fine point sharpie through the hole and sliding the bent edge along the cut edge of the plexi I was able to mark a nice even line all the way around the windscreen. I put several layers of black 3M electrical tape along that line to provide a non-stick surface to work to when laying up the epoxy and later adding filler.
This is how I used the template to mark the tape line. The grey tape above is some stuff Joe @ Van's told me about. It's a wide (2") electrical binding tape sold at HD & Lowe's. Epoxy won't stick to it either. It won't quite wrap around corners like the black stuff does, but it's a lot less expensive and you can put in wide swaths of non-stick area/protection very easily. Once I had a double layer of black vinyl I extended the edge back about 4" with the binding tape. This ended up working very well.
Starting to drill the windscreen to the roll bar. At this point I've final installed the forward brace to ensure the roll bar is exactly in it's final position, and also final fit the canopy latch/lock. Once it was drilled to #36, I tapped it for #6 screws.
Starting to install the clips along the bottom edge. I did this *after* installing the screws to make sure things didn't shift. I had it firmly taped down during both operations in any case, but I didn't want any movement once I started nailing down the location.
I had a lot of problems getting the forward bow of the slider and the roll bar exactly even all the way across. Down the right side (from the center all the way to the right) it was easily within 1/32". Very close. About mid way down the left side there is a gap. Maybe 3/32" at the worst, although the total length of mismatch is not more than 12 inches or so side to side. At any rate I thought I would have either a big honking gap between my top fairing and the slider that I would have to do something with later.
I'm posting this after I did the actual work. In practice, I was able to make it up with a couple of extra layers of glass and just allowing the fiberglass to naturally conform to the surface as I laid it up.
Along the slider, not only did I cover it with the electrical binding tape, but I also added about a 6" wide band of the cheap brown packing tape (some sort of plastic). I knew from previous experience that epoxy absolutely will not stick to it, so I added that as a top layer to make sure I could get the canopy open again after curing.
I was a bit concerned that I might have some flow through of epoxy into the gap between the two, but it ended up not being an issue at all. I did do a prepreg layup for the first coat, so it was already wet out when I put the fiberglass on, and all I did was paint the plexi with a thin coat to make sure there was a good bond between the plexi and the glass.
Holes are drilled and I'm getting ready to tap them.
Once the screws were installed, I installed the clips and started sanding the aluminum and plexi to make sure the epoxy would bond well.
I made the clips as small as possible, then dimpled the clip and skin and riveted it on with some countersunk blind rivets. I still had more sanding to do at this point as you can see the plexi still has some glossy spots.
N.B. I had bonding issues with the first layup across the top and had to do the whole thing over. I think this area here was done with some pro grade (blue) 80 grit. After the bonding problems I did a lot of testing with scrap plexi and sample layups. I eventually went to an aggressive 60 grit followed by 36 grit, which fixed the problem.
One note - although I had some issues with trying to get epoxy (west systems 205) & fiberglass to stick to the plexi, the one thing that stuck like crazy was superfil. I'm not sure what's in it, but it stuck to everything I put it on like a leech.
Lousy picture - these are the two front clips riveted on.
Side clips for the left side. As I mentioned, there was a pretty large gap right where the plexi comes down along the roll bar. what I did was put a clamp there to hold it down tight, which, along with the clips, gave me a tight fit along the bottom edge. I used my micro mix to glue the windscreen down along that line to within a couple of inches of the roll bar.
Once that was cured I was able to remove the clamp, and then apply filler along the rest of the edge to finish the attachment and provide a smooth even surface for the glass to attach to.
I first used dry micro to fill the gap. I added black pigment to make it blend in so it wouldn't be so obvious from the inside. (My original intention was to also apply several layers of black pigmented epoxy/glass over that, but given my later problem with the layup and my relative inexperience with glass in general, I opted to skip that step)
This is after several sandings and applying a layer of superfil. Between the two clips in the center I still had quite a depression that I felt was too much for glass alone to deal with. I masked off a small area with electrical tap and applied a thin strip of Superfil to raise it up a bit. Later when I glassed it I put a small narrow strip of prepreg in this area prior to putting the glass over the gap. That filled it in nicely.
Closeup of the aluminum roughed up and the line of micro dyed black.
This is after I applied that strip of Superfil to the gap and waiting for it to set up.
I did the same technique back on the pilots side to attach the plexi to the fuse prior to glassing.
Right side got the same treatment.
I'll do a second post since I have so many pictures.
