Matt's RV-7 Project » Canopy

Put the canopy to bed

Matt — Sun, 16 Sep 2007 18:51:19 +0000

To keep the canopy from having to sit on its own side skirts when it's not on the airplane, I threw together this very simple storage rack out of scrap lumber:

To capture the rollers, I knocked a 1" hole in a chunk of scrap 2×2 with a spade bit, then cut it half to make these little cup thingies. A wood screw from beneath holds each one in place.

In the back, the rear pins rest on wood blocks that are screwed to the bottom piece:

I carried the canopy upstairs and stored it carefully on its rack, on the guest bed. The exterior handle in the back makes it a snap to carry the canopy around solo – I think you'd need a helper if you didn't have the handle to grab.

And now I have a canopy bed again! I swear, that joke never gets old.

Canopy finishing touches

Matt — Sun, 16 Sep 2007 02:58:59 +0000

A while ago I ordered a nice machined aluminum handle for the exterior part of the canopy latch from Rivethead Aero. They took my payment and then disappeared for a couple months, but after repeated badgering I finally received my latch handle. It's really a work of art, which makes their disappointing customer service even more of a shame.

Anyway, I cut the latch shaft to the proper length after some fiddling and measuring. The handle is secured with a couple of setscrews, and for safety's sake I used a drill to put a couple of little dimples in the steel shaft for the setscrews to bite into. I just didn't feel right about the handle being attached solely by friction. Speaking of which, I used Vibratite on the setscrews, which should hopefully keep them from departing the aircraft.

The handle looks awesome:

And of course, me being me, I spent a bunch of time fiddling with the alignment of the handle to get it perfectly parallel to the centerline of the fuselage when the canopy is closed and latched.

At the forward end of the canopy slide rail, there's a brace that stiffens the overhanging portion against the F-706 bulkhead. The plans show this brace being constructed from a piece of threaded rod and some jam nuts, with a big ugly nylock nut on the end. I have a thing about wanting the interior of my airplane to not look like I built it in my garage, so I decided to dress this area up a bit. I used a piece of aluminum tubing, painted to match the rest of the interior, to cover the threaded rod and make it look a little nicer. At the forward end, I replaced the nylock nut with a swanky looking self-locking stainless steel acorn nut, which is a bit more professional looking.

I decided to keep going with the acorn nuts, using them in place of nylock nuts to attach the rollers to the canopy frame, as well as on the screws that act as the axles for the roller wheels.

Along the sides, I replaced all the #6 nylock nuts with more acorn nuts. I also used acorn nuts on the interior faces of the C-677 rear pin mounts, although it's hard to see in this photo. Now there are no exposed fastener threads visible on the inside of the canopy whatsoever. This is a purely cosmetic modification, but I really like the way it dresses up the interior.

I used Vibratite on all the screws and bolts in the canopy. At one point I had a regular assembly line going:

Next, I installed the canopy lock for good:

I cut a slot for the lock arm into the canopy track. In its normal unlocked position, the arm points forward, parallel to the track.

When it's locked, the arm swings down into the slot and prevents the canopy from being slid open more than a small fraction of an inch. Well, unless you were to beat on it hard enough – it's not particularly sturdy.

This is a photographic record to remind myself where I stashed the keys:

In the spirit of checking off the remaining items on my canopy to-do list, I installed the little track for the canopy shade:

Then I whipped up these little air baffles out of some leftover angle stock, and fitted them to the fuselage and canopy. They'll eventually be painted to match the interior, and will be attached to the longerons with a couple rivets. They butt up against the inside of the side skirts at the rear of the canopy, and will serve to seal up the small gap back there.

After thinking about it for a few days, I decided to drill out the front two rivets on each side of the canopy, where the leading edge of the fiberglass aft skirt attaches to the side skirts. I replaced the previous 3/32" rivets with 1/8" rivets sitting inside tinnerman washers, which makes me feel better about the rivets not puling through the fiberglass. The airflow is going to try to peel the fiberglass skirt back in this area, so I wanted to beef up the attachment a bit.

Well, that about does it for the canopy. Next I'll build some kind of a frame or platform to set it on, and stash it in the house so it will stay out of the way and not get scratched.

Assembled the canopy

Matt — Mon, 10 Sep 2007 01:50:54 +0000

I started the day by riveting the C-791 skirt braces to the side skirts. I also applied a strip of UHMW tape along the bottom edges, to keep the skirts from scuffing the paint on the fuselage.

I also put some UHMW tape at the trailing edge of the aft skirt, for the same purpose.

The first part of the canopy to get permanently riveted to the frame was the little lock bracket, which I attached with a couple of LP4-3 blind rivets.

Then I clecoed the whole canopy together, inserting screws along the sides, and checked the fit one last time. Finding everything to be satisfactory, I used more LP4-3 rivets to attach the tops of the skirt braces to the inside of the canopy frame.

Here's a little trick I picked up from somebody's website: by drilling the fastener holes 1/16" oversize and making tiny little bushings out of 1/32"-wall surgical silicone tubing, you can keep the fasteners from ever contacting the insides of the holes. Theoretically this should help prevent cracking, but it ought to also have the side benefits of preventing rattles and making the canopy more watertight. Anyway, it wasn't a big deal to make these little bushings, and I'm all for anything that will help keep my canopy in one piece.

With everything clecoed in place, I applied electrical tape to the plexiglass along the edges of all the various skirts and cover strips, and followed up with blue masking tape to cover any remaining exposed plexiglass. I prefer this combination when I need to very precisely mask around objects with irregular contours, and just about everything on the canopy is curved in some way.

Here's where the construction photos stop, because for the rest of the afternoon I had sticky fingers, the clock was ticking down the working time of some glue, and Mary wasn't home to help with camera duties. So, here's a textual description of the next four hours' worth of work:

The weather outside was unseasonably cool today, so I had to keep the garage door closed so the temperature would stay up in the 80's and make the plexiglass happy. Because of the solvents and glue I was using, I had my VOC respirator on the whole time to keep from gassing myself.

I began by removing the aft skirt and the center and forward cover strips and putting down a bead of Lexel on the exposed plexiglass. The side skirts were non-removable at this point, but I was able to remove all the clecoes and force Lexel down into the gap between the side skirts and canopy. If you're interested, a toothpaste-tube-sized container turns out to be enough to do one canopy.

I made a special effort to goop a bunch of Lexel into the cavities formed by the 7/16" holes in the plexiglass where the stacks of washers go to support the exterior handle. It wouldn't do to have water leak in along that path. Some masking tape on the interior side formed a temporary dam to keep the sealant from dripping down into the fuselage.

After all the sealant was dispensed, I tightened the nuts on the #6 screws that attach the plexiglass to the side skirts, and then put the aft skirt and cover strips back on and clecoed the canopy back together.

After tightening the screws and reinstalling the clecoes, there was a tremendous amount of sealant squeeze-out to deal with. I cleaned up the biggest blobs with popsicle sticks, and then removed the masking tape, but there was still a bunch of sealant oozing out from under the exterior pieces. The surfaces of the skirts and cover strips were also heavily contaminated with Lexel. I dealt with this by removing one cleco at a time, cleaning the affected area with naphtha, and replacing the cleco. Naphtha was the only thing I'd found that would remove Lexel without damaging plexiglass, and I bet I used a half-gallon of the stuff. Plus a bunch of shop rags and elbow grease.

Then I started replacing clecoes with rivets, using the cool pneumatic puller I bought at Oshkosh to pull the blind rivets. This tool was totally worth the investment, as it almost completely eliminates the risk of gouging the surface of the part with the broken-off mandrel that you get when you pull pop rivets with a hand tool. To me it was a no-brainer to buy this tool in order to protect my canopy from damage. Plus it was on sale.

Installing the rivets caused more Lexel to squeeze out, so I revisited each area with naphtha as I pulled the rivets. Ideally I'd like the sealant to be minimally visible – the canopy will still be watertight if the sealant is out of sight underneath the skirts, and it will look better that way.

I kept repeating the last two steps until I ran out of holes, and then suddenly the canopy was done. I pulled off the remaining protective plastic, and there it was in all its glory:

Same view from the other side:

The aft skirt (held in place with tinnermans under the rivet heads as planned) fits as perfectly as can be:

There is very little resistance in the rollers – the canopy can be opened and closed with one finger.

The exterior handle looks like it was made to go on an airplane:

The only perceptible gap between the side skirts and the fuselage is towards the very back, just in front of the fiberglass aft skirt. This is a pretty typical place for an RV to have a gap, and mine is a lot smaller than most other airplanes I've seen. Later on, I will seal this by riveting pieces of angle inside the fuselage to close up the gap.

Mary eventually came home and took the requisite triumphant photo of me enjoying the view from inside my newly completed canopy:

All in all, I'm extremely pleased with how the canopy turned out. There are a couple more little details to finish up, but the hard part is over. This has been, without a doubt, the most difficult and frustrating phase of the project to date, but I have emerged victorious. And now, for the celebratory libations!

Canopy lock improvement

Matt — Sun, 09 Sep 2007 03:00:12 +0000

I realized that I could improve the security of my canopy lock by using the little anti-rotation ring that comes with the lockset. I ground off one side so it would fit inside the lock bracket, and drilled four small holes to accommodate the little bent tabs that are supposed to bite into the wood surface of a cabinet or drawer.

This should slightly decrease the chances of anyone being able to force the lock open, although it is still mostly a courtesy device to keep honest people out.

Later on I primed and painted the retaining ring to match the rest of the canopy interior.

I also picked up a new toy this week – a mini random orbital sander. To try it out, I polished the center canopy slide rail, using progressively finer sanding discs and followed by buffing with Flitz. The results weren't too bad – I will probably polish the side rails the same way, when I eventually remove them in order to touch up the paint on the canopy decks.

Further canopy painting

Matt — Thu, 06 Sep 2007 00:23:53 +0000

Unless there are any runs, drips, or errors to sand out and repaint, this should be the final coat on the canopy frame:

More canopy painting

Matt — Mon, 03 Sep 2007 23:26:59 +0000

Continuing the disassemble the canopy frame… one of the screws that attaches the roller brackets was a real pain to extract. Good thing I have a couple extra screws laying around.

The paint on the canopy latch handle looked good the next day, though it needed a small amount of touch-up.

…so, I decided to paint some more canopy pieces and see how it turns out. If it goes badly – well, I was going to have them sandblasted anyway, right?

Canopy latch arm being primed, later to be painted black like the rest of the pieces:

The powder coat was cracking off the canopy frame around the weld where the forward bow and center tube come together, so I ground it off. I inspected the rest of the frame carefully, looking for more flaking areas, but I didn't find any.

This is my excuse for a "paint booth". I primed the canopy frame thoroughly to promote paint adhesion.

Painting the interior surfaces… I used three light coats.

Unlike the primer I use, the black paint takes hours and hours to dry. The canopy frame was still tacky by the time I needed to start barbequing, so I carefully moved it inside the garage to finish curing overnight. When I next get a chance, I'll flip it over and paint the other side.

Materials testing

Matt — Mon, 03 Sep 2007 04:00:44 +0000

I have plans to use two new substances during final assembly of the canopy, and I wanted to do a materials-compatibility test first to make sure that neither of them will eat plexiglass or promote cracking (as good-old regular Loctite will, apparently).

The first material to be evaluated is Lexel, a clear rubber caulk that I plan to use between the plexiglass and canopy skirts:

The second is Vibra-Tite, a sort of paintable threadlocker. It has the same function as Loctite, but supposedly minus the inconvenient plexiglass-destroying side effects.

I dug up the piece of scrap plexiglass on which I've been practicing drilling and countersinking, and cut and drilled a small piece of scrap aluminum to fit it. Then I masked off an area just outside where the aluminum piece will go, and applied a bead of Lexel:

Then I riveted and screwed the aluminum to the plexiglass and removed the tape, leaving a decent looking caulk edge. I also smeared on a blob of Vibra-Tite. Why two different kinds of fasteners? So I can properly judge the amount of squeeze-out from both rivets and screws.

I'll let this all cure for several days and then examine it closely to make extra sure than none of this stuff is going to destroy my expensive canopy (and incidentally cause me to become an alcoholic).

Canopy parts prep

Matt — Mon, 03 Sep 2007 02:00:41 +0000

I countersunk all the rivet holes in the fiberglass aft skirt:

Where the 1/8" rivets will attach the skirt and plexiglass to the frame, I am going to use #4 tinnerman washers under the rivet heads to keep them from eventually working through the fiberglass. Once it's all painted, you won't be able to tell they're there.

I drilled all the remaining holes in the skirts and cover strips up to #30:

I also countersunk the line of rivet holes along the side skirts where they will be attached to the frame with flush blind rivets:

I cleaned all the aluminum parts and got them ready for painting:

Outside, I laid down a plastic tarp (weighted down with my entire collection of bucking bars) and commenced priming and painting the interior surfaces of the various canopy skirt pieces. I'm using Rustoleum flat black enamel throughout the inside of the canopy, to keep the glare down.

The inside surface of the fiberglass aft skirt also got the black paint treatment:

I scuffed up the powder coat on the canopy latch handle, cleaned it, and sprayed it with black paint too. In this photo it's sitting on a nail driven into a board, which is why it looks like the Oscar for Best Canopy. I'm debating whether to paint the canopy frame and rollbar myself, or send them out to be sandblasted and powder coated black. This piece will help me decide which is the best way.

A big stack of canopy pieces is now painted black. I'm like a regular Mick Jagger.

While waiting for successive coats of paint to dry, I enlarged all the holes in the canopy plexiglass. Each hole that will receive a 1/8" pop rivet has been enlarged to 3/16", and every hole that will get a #6 screw has been drilled up to 1/4". This is more aggressive hole-enlarging than the plans call for, but I have a strategy… you'll see.

I enlarged the two holes through the canopy where the exterior handle bolts to the frame, drilling them up to 7/16" with a unibit. Scott had previously made me some neat little aluminum spacers for this application, but through experimentation I found that a stack of washers worked just fine (sorry Scott – I still owe you anyway).

Here's an approximation of how the exterior handle will attach, using some nylon washers I had at hand:

I do believe I'm finished cutting and/or drilling the sliding canopy, and no cracks yet. Huzzah!

Canopy anchor block modification

Matt — Mon, 03 Sep 2007 00:00:12 +0000

The normal way to remove a completed sliding canopy from a side-by-side RV is to remove the bolts that attach the WD-644 canopy rollers to the slider frame, then lift the frame up off the rails. I realized that if I could make it relatively easy to remove the rear anchor pin blocks (which also function as the aft canopy stops) it would then be a cinch to instead slide the canopy straight back until the rollers slid out of the side rails. By removing the canopy that way, you avoid tearing up the paint on the roller weldments, and you don't have to mess around with trying to get a wrench on the nut that attaches the roller to the frame.

The challenge, though, is that the design of the rear anchor block mounting bracket prevents you from removing it from the fuselage unless the canopy is removed first. You have to start by removing the screws that capture the plastic block within the U-shaped bracket, so that you can remove the block and get access to the bolts that hold the bracket to to the fuselage longeron. But of course, you can't get at the screws in the first place, because the canopy side skirts are in the way.

So, my bright idea was to modify the C-677 rear pin anchor block mounting brackets by riveting some MS21051-L3 nutplates inside:

Now instead of using bolts through the top of the brackets and nuts on the underside of the longeron, the bolts come up from underneath:

To provide clearance for the nutplates and bolt threads, I drilled very slightly into the plastic anchor block: (hard to see in this photo)

Now I can remove the entire anchor block/bracket assembly from inside the fuselage, then slide the canopy backwards off the rails until it can be lifted straight up and stored safely. Hopefully this will prove to be a useful modification down the road. I will mark the bolt heads with inspection lacquer and check them periodically, although they are plenty snug in the nutplates right now.

Fiberglass canopy skirts part XVII

Matt — Tue, 28 Aug 2007 03:00:44 +0000

I used the hole finder to drill the last two holes in each side of the canopy skirt – they're the two silver clecoes in the middle of this photo. Also notice how the fiberglass skirt here on the right side of the airplane is slightly too long to match up to the edge of the C-660 side skirt.

On the left side, the skirt is slightly too short. Something must have gotten misaligned pretty early on. But it's no matter – I just cut a slight (1/8") taper on the rear corner of the left side skirt, and sanded the fiberglass skirt to match. Then I cut the same taper on the right side skirt and trimmed and sanded the fiberglass to match over there too. (Heaven forbid I shoud have an asymmetrical canopy!) It looks nice now, even though I seem to have forgotten to take a picture.

On the left side skirt, I trimmed an inch off the upper rear corner, where the bottom-most rivet hole in the plexiglass had way not enough edge distance on the aluminum skirt. This will all be covered with the fiberglass skirt once it's all put together.

Once the bottom edge of the aft skirt was finalized, I sanded a nice round profile on the protruding front corners, using a quarter to gauge the radius. (I used a Kentucky state quarter, but I think you could use any of the southern states with good results.)

Fiberglass canopy skirts part XVI

Matt — Sun, 26 Aug 2007 23:37:47 +0000

Overnight I figured out how to fix the misalignment of the canopy skirt mounting holes. The nice thing about fiberglass is that you can usually fix your mistakes with enough patience and sandng.

I applied a layer of packing tape over the holes on the exterior surface of the skirt:

From the inside, I used a popsicle stick to force a thin epoxy/flox mixture into the holes. After I took this photo, I came back and squeegeed off the excess flox.

Once that was cured, I removed the tape and did the same thing from the exterior side, to fill both sides of each hole. When that was cured, I sanded it all flush. Here's the result – no more holes:

Then I put the skirt back on the plane, and after a great amount of measurement and double-checking I re-drilled the holes. This time it came out straight.

In some places, yesterday's holes were okay, but in others they were substantially off:

Since the alignment of the skirt to the plexiglass and frame was now acceptable, I went ahead and drilled most of the holes that attach the rear skirt to the C-660 side skirts. There are still a couple holes on either side that need to be drilled (where the obvious gap is in this photo) but I wanted to finalize the alignment before I removed the skirt again.

Without removing the skirt from the plane or otherwise disturbing the alignment, I drilled straight through the skirt, canopy, and steel frame with a 1/8" plexiglass drill, enlarging the holes in the skirt and frame to the final size (note copper clecoes in this photo). The holes in the canopy were already at 1/8", and will be enlarged to their final size of 3/16" soon.

Back on the worktable for more surface preparation and pinhole filling:

Fiberglass canopy skirts part XV

Matt — Sun, 26 Aug 2007 01:42:12 +0000

Yet more sanding… this time down to 400 grit.

I didn't like the blunt shape of the leading edge of the skirt up in the thickest part of the middle where the glass layers were doubled up, so I sanded it to get a gentler slope. Of course this means I'll have to do more pinhole filling here.

I re-drilled the skirt to the canopy using a hole finder, since the previous pilot holes got closed up by fiberglass filler. I think it must have slipped a little bit this time, though, since the alignment is ever so slightly skewed. It still fits and nobody but me will know it's crooked, but I may yet try to fix it. Not sure what I'll do about this yet.

I clecoed the C-653 cover strip in place and marked a line where the rear skirt overlapped it. Later I trimmed the cover strip so it ends just at the leading edge of the skirt. In retrospect, it would have been cool to mold the fiberglass skirt to fit over the cover strip perfectly, but I didn't think of it until it was too late. Oh well, a simple trim works just as well.

Also, my propeller governor arrived today. It's a PCU-5000 that I picked up for a good price through the VAF group buy that was organized a few months back.

Fiberglass canopy skirts part XIV

Matt — Mon, 20 Aug 2007 00:04:21 +0000

I spent an hour sanding off the previous application of Superfil. Does this sound familiar? Anyway, this time I went all the way down to 220 grit paper – previously I'd been staying at 80 grit.

Now that the shape is basically how I want it, it's time to start preparing the surface by making it smooth and filling pinholes. For this job I'm using DuPont 210S, a single-part surface primer.

You're supposed to spray this stuff on, but it was too windy outside to spray effectively, and I didn't feel like getting out my spray gun and trying to mess with painting inside the garage. So, I just brushed the surface primer onto the skirt with a cheap foam brush. I'd never do that for a finish coat, of course, but for a filler coat it actually worked pretty well.

I put one one heavy coat, sanded with 400 grit, then applied two additional lighter coats without sanding in between. No rhyme or reason, I'm just winging it based on what seems reasonable as I go.

I kept the skirt up off the table with little balls of aluminum foil, to prevent the surface primer from getting all blobbed up along the bottom edge.

This is a picture of the third coat dying. The brush marks should sand right out.

It's starting to get smooth and look pretty good… is that the light at the end of the tunnel I see up ahead?

Fiberglass canopy skirts part XIII

Matt — Fri, 17 Aug 2007 03:00:40 +0000

Here is what the skirt looked like after being popped off the airplane:

I marked a rough trim line, and then used a cutoff wheel to trim the excess glass to within 1/8" of the real shape of the skirt.

Then I block-sanded all the edges until the overhang was completely gone.

I sprayed another coat of grey primer…

…and sanded most of it back off again. Looking pretty good, only a few very minor low spots left.

I mixed up a big batch of Superfil and squeegeed a thin skim coat across the entire exterior surface of the skirt. Most of this will get sanded off, but what remains will fill the fiberglass weave and become the basis for future efforts to get a smooth surface.

Fiberglass canopy skirts part XII

Matt — Mon, 13 Aug 2007 00:26:59 +0000

I cleaned up the excess flox on the inside and outside of the doghouse, and then trimmed the slider seal block to a shape approximating what the plans specify. There's no need to be super exact here, especially since I'm not trying to make the seal block fit into a pre-bent aluminum doghouse. As long as it fits beneath the skirt and seals okay, the shape is fine.

I put some packing tape on the fuselage adjacent to the forward end of the canopy track, and followed it with a thin layer of Superfil.

Then I put the canopy skirt back on the airplane, fixed in place with clecoes and held down with buckets of heavy stuff. This is all part of the effort to get a perfect seal and keep out cold air and rain.

Several hours later, I sanded off the excess filler and was left with a nice flat bottom surface that should seal pretty well.

After wiping down the exterior surface in order to get rid of all the sanding dust, I put the skirt back on the airplane, with a fresh new (i.e. hole-free) plastic drop cloth between it and the rest of the airplane.

Then I painted a layer of epoxy onto the skirt, and laid up three plies of 6-oz cloth over it. Afterwards, I spent some time squeegeeing out excess epoxy and making sure the peel-ply was properly adhering everywhere.

The goal of this final layup is to provide a durable outer surface for the skirt that will keep the buildups of filler from cracking or getting dinged. Normally the experts advise you to never lay up glass over micro, but since the canopy skirt is not a structural piece I'm not terribly worried about the reduced strength that results from sandwiching micro in between glass layers. I also made sure to rough up the surface with 80 grit before doing the layup, in order to give the epoxy plenty of surface to grab onto. Considering that the plans call for fiberglass over filler when constructing the fairing for the bottom of the windshield, I judge that the same approach ought to be okay for this application too.

Fiberglass canopy skirts part XI

Matt — Thu, 09 Aug 2007 02:15:12 +0000

After one last round of sanding, I'm finally happy with the shape of the doghouse:

Remember how I cast a recess out of flox for the plastic slider seal block to perfectly fit inside the doghouse? Yeah, that wasn't such a good idea. Well, it actually was a good idea, just poorly executed. I should never have tried to cast something like that without all the parts in their final positions – when I put it all on the plane, nothing fit together. So, I had to laboriously grind out most of the flox with my Dremel tool.

I put tape down to protect the fuselage, slide track, and seal block, then stuffed a new batch of flox into the open end of the doghouse and set it down over the plastic block. It's only inserted halfway because I haven't trimmed the front end per the plans yet. As long as the exterior surface is cast correctly I can dremel away any excess flox buildup inside the cavity.

While the flox is curing, the skirt is clecoed to the canopy, and the doghouse is weighted down with a bucking bar that I taped in place. This time around, everything should be in its final position while the goop dries.

But just look at the profile of that canopy skirt, eh? Eh?

Fiberglass canopy skirts part X

Matt — Sun, 05 Aug 2007 15:58:54 +0000

More sanding, and the slider seal doghouse shape is starting to appear. I like the way Superfil sands – it's a little easier to contour than straight micro.

Another layer of filler to help build up the shape:

I smeared Superfil all along the bottom aft edge of the skirt, so I can sand it down to a nice flat surface for better sealing against the fuselage skin.

While the above was curing, I played with the side skirts a bit, using my shrinker to try to get them to fit the fuselage better at the aft ends. The fit is marginally better now, although since I only have a minimal grasp of what I'm doing with the shrinker I probably wouldn't try this approach again. Still, it seems to fit okay and it looks fine after I buffed out the marks left by the shrinker jaws. There is still a gap of 1/16"-3/32" but I am going to leave it alone and seal it against air leaks using a different method (stay tuned for a future installment).

After 10 hours or so, the filler from this morning was cured enough to sand.

I applied a little more filler in order to fine tune the shape of the doghouse area a little more.

Here's a little detail that may or may not help seal the canopy against leaks, but I think it will at least end up looking cool. I covered the C-679 slide track seal with packing tape, then pressed it down into a bed of flox inside the doghouse:

After letting it cure for an hour, I popped the seal out of there, leaving a perfect impression behind in the flox. Once this is fully cured, I will sand and fill as necessary to give a nice surface. The goal here is to make the C-679 seal perfectly and leave no path for cold air to leak past.

Fiberglass canopy skirts part IX

Matt — Sun, 05 Aug 2007 00:15:02 +0000

I spent the morning sanding Thursday's application of filler, then sprayed it with another guide coat of primer and sanded that off too. The result was pretty good – the light grey areas shown in this photo are actually historic low spots that are now filled and sanded level. The dark grey spots are the only remaining low areas still needing filler. Most of these are in the area of the slider seal "doghouse" which I have yet to do much with.

Since I am running low on micro, I mixed up a batch of Superfil from a quart kit that I'd bought a while back. I've never used this stuff, but people seem to rave about it. Each of the two components is the consistency of peanut butter, and you mix them 2:1 by weight or volume. I eyeballed three plastic spoonfulls of blue goo to one and a half of tan goo.

Since I had a little extra mixed up, I started applying filler to some of the more egregious areas on the underside of the canopy skirt. I don't intend to go for a perfect finish on the bottom, since it will be hard to see from inside, but I do want to at least fill in the voids.

Fiberglass canopy skirts part VIII

Matt — Fri, 03 Aug 2007 01:54:25 +0000

I finished sanding off all the high spots on the canopy skirt:

Then I smeared on more micro filler, thus making more high spots to be sanded off later.

Hopefully the remaining low spots will become smaller after each fill/sand cycle. Eventually this should converge on a nice-looking surface, but there's a lot of work between now and then…

Fiberglass canopy skirts part VII

Matt — Wed, 01 Aug 2007 02:24:57 +0000

I sanded on the canopy skirt for about an hour tonight, making a big dusty mess of my garage:

After I did all the sanding I thought I could possibly do, I shot a coat of grey primer on the skirt.

Once the primer was dry (which was pretty quick since micro filler is so porous) I sanded the entire thing some more. The spots that remained grey are the low spots that I'll need to put more filler on. I'll have to do that later since I'm too tired to mess around with gooey stuff tonight.

By the way, I've become a convert to Norton 3X sandpaper. It's significantly more expensive than the no-name stuff, but cuts better and is way more durable. To me, anything that makes fiberglass sanding go quicker is worth it.