I spent quite a bit of time trying to figure out how to draw the window outlines on the TB, especially since I have raised the front of my TB by 1". Somehow I do not seem to have enough information from Fig. 18 to draw out the windows. So I visited the Cozy FAQ and found very useful instructions (Q18.8). Based on that, I was able to draw out the window outlines in 10 minutes. However, the instructions are for a standard TB and mine is raised 1" at the front. Therefore, I have to improvise a bit. Cosmetically, I feel the inner lines of the windows should run parallel with the cut line, otherwise it will look funny. So, I replaced the FAQ instruction's inner lines with 2 parallel lines 2 1/8" from the front and aft of the cut line. The rest remains the same. Initially, I used strips of masking tape on the TB for trail marking the outlines. Once I was done with the graffiti, I removed the masking tape and drew the outline directly onto the surface of the TB.
I placed the window panes (from Todd's Canopy) over the marked windows to make sure they are not too small and at the same time fit the TB curvature. I have 3/4" excess on most edges except at a couple opposing corners where I have about 1/2" excess. I think I have maximized the use of the window panes with the layout. I placed strips of 3M vinyl electrical tape on the window pane, along the inside edges of the frame. Then I re-traced the opening on the tape. These marked frame 'outlines' will be used for trimming the window panes as well as re-positioning in the future.
I drew a border (~3/4" wide) along the previously marked 'outline' and trimmed the window pane accordingly. I found the grinder/cutting wheel worked best. Then I cleaned off the edges with my palm sander.
Once I was comfortable with the outlines, I proceeded with the cutting step. First I used my largest hole saw (2 1/2") and removed 8 large holes - one at each of the corners. I must admit I was a bit apprehensive with the first hole... I was pleasantly surprised that the hole saw went through the TB in about 15 seconds - actually startled me a bit... I was careful not to cut too close to the edges just in case the hole saw causes any delamination - fortunately, none occurred.
Next, I used my FEIN tool to trim tightly along the 4 sides - joining the holes. With a bit of trimming, I was able to remove most of the panel. Then comes the Dremel with a coarse sanding drum, I cleaned off the rounded corners as well as the rest of the window edges. Since I am not as skilled as some Cozy builders with the Dremel tool, I smoothed out the straight edges by running my palm sander over it. My finishing touch included a wood dowel and fine grit sand paper for an all around smooth edge.
The plan called for removing ~3/4" of foam along the entire window frame. It was a bit more difficult for those who bought the TB from Featherlite because the honeycomb is much harder to remove. I ended up using 2 different types of sanding/grinding discs to get to the appropriate 3/4" trench depth (I was not able to find a sanding drum with small enough diameter to fit inside the trench without taking the glass out in the process). I had to be real careful not to nick the surface glass with the sanding disc going 2,200 rpm. I also took a small piece of scrap fiberglass and wrapped 2 different grit sanding papers - to help smooth out the inner surfaces of the trenches. I think it is most important to remove all remnants of the honeycomb 'webs' (especially the ones close to the edges) such that the window panes can be flush with the frame. This turned out to be a very time consuming process - and patience is definitely required. I was able to complete the task in ~4 hours with a couple of small nicks. I removed the nicks by sanding down the edges a bit.
It took me a while to figure out what the plan means on this step. Basically this step is for making an opening for slipping the panes into the trenches. I flipped the TB on its back and drew out the 1" strips along the long edge of each of the windows. Again, I ran into difficulty in removing the glass (after its been cut) from the honeycomb materials. By the time I almost completed the 2nd window, I realized using a scraper and hammer was a lot more effective in separating the glass from the honeycomb. For the last 2 windows, I used the scraper and hammer first, then trim/cut the glass strips. That was much easier and quicker.
Once I removed the inner strips, I ground off the residue honeycomb roots. I also took a sander to the back side of the strips so that they are ready for bonding later on.
I taped a straight edge on the panes (~1/8" from the edge of the frame) and roughed up the plastic surfaces with a Scotch scrub pad. If you look close on the picture (left), you can see the roughed up border and a clear 1/8" strip - along the vinyl tapes. I just wanted to make sure the rough edges do not show up above the window frame.
I made up some wet flox and 'spooned' it along the trenches of the window frame. Then I used a narrow stir stick and pressed them further into the trenches (~1/2"). Next I spread the rest of the wet flox along the perimeters of the window panes (both sides). Once completed, I slipped the panes in place, using the white tape (above) to line them up appropriately.
As many builders before me, instead of using clecos per plan, I used 3 strips of particle board, multiple foam blocks, stir sticks and small pieces of wood to prop the panes so that they are flush against the exterior skin of the turtle back. I was real careful not to get any flox onto the acrylic panes. I fit two windows at a time, so the whole process took me a couple days.
[Hindsight] Evidently, I was not careful enough and I ended up with few smears of flox/micro from my glove's finger tips on the panes. I probably have to contact Todd Silver (who supplied my canopy) or archives to figure out how to remove them.
Once the flox that held the panes in place cured, I flipped the TB back on its back and proceeded to re-glass the 1" strip over the wide opening. In my case, I have a step between the top of the honeycomb layers and the top of the pane surface. I didn't like to have a step there (as shown in plan Fig. 20), so, I decided to cut a real thin strip (~.1") of foam to level out the two surfaces so that the glass strip will lay down nice and flat. Note the thin foam strip (light yellow) and the 1" glass strip I removed earlier?
I made some wet flox and spread it (like peanut butter) on both sides of the foam as well as the bottom side of the 1" glass strip. I fit everything back in place, then I added a 2" BID along its seams. With a strip of plastic between the BID and scrap boards, I weighted them down to cure.
I did not have to use any thin foam strip on the small windows for the 1" glass strip to fit nicely (don't know why?) . However, I clamped them down to cure as well.
As I pressed the window panes against the outer TB glass surfaces in the above steps (fitting in the windows), I noticed that I will have a gap between the inside surface of the panes and the window frame. I checked the archives and looked up many builders web sites and found no discussion on this issue. Regardless, I decided to fill in the gap with micro - I hope I won't regret it because I have not read the plans very far ahead at this point. Here's a picture of the gap after I filled it with micro.
After the micro cured, I removed all the vinyl tapes so that I can put protective covers over the window panes. It turned out I have quite a bit more flox/micro smears along the edge of the tapes. I searched through the archives. All the recommendations I found were directed towards scratches and paint over sprays - no flox or micro. I decided to post the question in the Cozy Forum.
I received 8 responses (5 private, 2 Cozy forum and 1 personal) within 24 hours. Amazingly, only two recommendations were similar. Since most of them are private, I decided to list them here, because they are valuable information and they will not be in the archives. Here's are the responses:
1) I don't have experience with removing flox, but if all else fails you can sand it off. This works on canopies and polycarbonate in general (CD's, DVD's):
Pick a grade of sandpaper in line with the size of the scratches being removed, and work your way from there through 600, 800 grit to rubbing compound. Then finish with Maguire's Mirror Glaze (have never seen an acceptable substitute). This does two things, 1. polishes by removing a (very) thin layer of plastic off the top, 2. leaves an optical coating (~silicone?) that fills the micro-valleys to restore transparency (3. smells like airplanes--with a whiff of hot cockpit and jet exhaust, can take you back 30 years, to the flightlines of yore :-)
2) You need to order a Micro Mesh kit from Wicks or Spruce. It's for removing scratches epoxy from plexi-glass
3) Get yourself some Novus #1 and #2.
the micro off with a wood mixing stick. I would not use anything harder than a
piece of wood or your finger nail.
With a cotton cloth and Novus #2, rub off the smears of epoxy. This stuff works like magic. Finnish it off with #1
To find out where you can get Novus products, run a search on Novus.
4) See if you can pop it off with the edge of a razor blade held parallel to the surface.
5) I would do a little testing to make sure that vinegar doesn't etch or otherwise damage the plexiglas if left on for a period of 24 hours or so. If not, maybe soak a rag or towel with vinegar BEING VERY CAREFUL not to leave any drops of vinegar on surrounding glassed surfaces, cover it with plastic or something to keep it from evaporating (maybe use some electrical tape to tape plastic wrap to the window), and leave it on overnight. I find that when I have tools that have accumulated epoxy, if I leave them soak in vinegar, it will soften the epoxy enough so flake it off. Again, make sure it won't harm your plexi (I don't think it will, but better safe than sorry). Maybe there's a sure-fire suggestion out there somewhere, but if all fails, try this one.
6) I found that a couple of areas where I had some small trails of epoxy overruns. They popped right off with an x-acto knife applied close parallel to the surface to cleave off the offending blob. Not a scratch.
7) rub it off with vinegar, but test it on a scrap piece first.
With so many options, I wouldn't know which one to pick. I decided to take the vinegar approach first because it is the mildest chemical (basically a mild acid) and its not mechanical, therefore less chance of scratching the plexi surface. I put some vinegar on a scrap piece of plexi-glass and observed no negative reaction.
With a leap of faith, I wet out a cotton glove with vinegar and rubbed it over a small ambiguous flox smear. To my surprise, the flox starts to flake off after ~10 passes. Once I got the flox off, I wiped over the area with a wet cotton glove (to dilute and remove any acid residue), then followed with a dry cotton glove. It would be good if I have three hands for this process - but not today...
I also had a few small scratches that I have created earlier with a stir stick - trying to scrape off some epoxy droplets. I used the Novus #2 and #1 per above recommendation. It took hardly any effort and the scratches were gone. The picture (left) shows the vinegar, gloves, Novus #1 & #2 that I used and my completed turtle back.
I did not try the rest of the recommendations, but I bet they'll work just as well. All in all, the vinegar worked reasonably well, no chemical reactions on the plexi-glass and no new scratches in the process. One important point - I did not leave the vinegar on the plexi-glass for long. Just long enough to soften the flox. Then I wiped it off with water and dry cloth immediately afterwards.
On to the next section...