Masking Canopy For Fairing Lay-Up

As mention in the previous post, Van’s instructs the builder to remove 1/8" of the foam material from the top edge of the canopy frame arms. To facilitate the removal of the foam and epoxy mixture, a Dremel outfitted with a sanding drum was used. The epoxy/flox mixture is really tough on the sanding drums ... it took four or five to get the job done.

Using the Dremel outfitted with a sanding drum to remove 1/8" of the foam from the top edge of the canopy frame’s arm.

Finished removal of the foam from the canopy arm on the right side of the canopy frame.

The finishing kit comes with a large drawing that has the templates for cutting the fiberglass cloth and masking the canopy. I just could not bring myself to cut up the drawing so decided to procure a roll of tracing paper to create templates. This turned out to be quite time consuming and frankly, stupid on my part. Hindsight being 20/20, it would have been much easier to just order a second printed page to chop up.

Using tracing paper to trace the shape of the templates so they can be cut to shape and placed onto the fuselage to establish the masking line for the canopy without destroying the original drawing sheet. This was a total waste of time .... should have just ordered another drawing to chop up.

After wasting a lot of time tracing and cutting out the templates, they were taped in place on the fuselage. It quickly defines where the lay-up will reside so there is no guess work from this point on.

Placing the template for the left side into position.

Van’s instructs the builder to use a good quality electrical tape to create the masking line for the lay-up. The templates only cover the sides of the canopy and the builder is to visually “continue the line” from one side to another.

Left template in position … one can see the template stops far short of the apex of the canopy’s curve. Also, the dashed line on the bottom of the template will be the bottom edge of the canopy fairing.

Red electrical tape was chosen over black because the epoxy for the first lay-up will be died black to hopefully give a good look from the inside of the cockpit … using a color other than black will make it much easier to visually align the first layer of the lay-up to the edge of the electrical tape.   I found "continuning the line" is not to be that easy and ended up with the tape having an uneven wavering curve. As can be seen (possibly) in the photo below … I even tried to use pieces of tape as guides but did not like end result. So a redo is in order.

The red electrical tape will define the aft edge of the fairing lay-up onto the canopy.

Think I will try using a long thin strip of tracing paper to complete “the line” from one side to the other and then place the electrical tape adjacent to the tracing paper. Hopefully, this will yield a smoother looking transition.

Shaping The C-1208 Canopy Foam

This was a slow week for making forward progress on the DOG Aviation RV-12. Having returned from Chicago after attending Marty’s memorial service, I have admittedly been in a little slump … and did not spend much quality time at the airport. Was hoping to fiberglass this weekend but a cold front has moved in … so will wait a few days for the temps to get back into the high 70’s or low 80’s before doing the glass work.

The recent drop in temperatures is a stark reminder that cold weather is right around the corner for this part of the country. After the canopy fairing lay-up is completed, I may not take the time to complete the finish sanding and smoothing of the fiberglass because there are plenty of tasks yet to be done that are somewhat temperature sensitive. The fuel tank needs to be assembled and sealed with Pro-Seal, along with sealing the firewall and miscellaneous places around the instrument panel and rear window. Plus, I would like to paint the fuel tank and some of the aluminum parts that came with the engine kit, and all of that requires warm temperatures … time to get seriously motivated again.

I did get a couple of small tasks accomplished this week beginning with shaping of the C-1208 canopy foam. It was nice to be able to roll the fuselage outside to sand down the foam blocks and not have a mess inside the hangar to clean up. Van’s suggests using a 15-18" long sanding block, but not having one that long (nor having a clue where to find sandpaper that long) I just carefully used a regular sanding block with 80 grit paper on it. Most of the block gets sanded away and although I could have used power tools, the foam block sands easily so I took my time shaping the block by hand.  It took about 45 minutes or so per side … good therapy.

Sanding the left C-1208 canopy foam and beginning the shaping process.

Completed right C-1208 canopy foam. The foam conforms nicely to the shape of the canopy skirt as can be seen in the area between my fingers.

Once the canopy skirts were sanded to shape the little aluminum inserts for the bolt tunnel were trimmed to the approximate size and bonded in place with a mixture of epoxy and flox. This is an addition I’m making and not part of the Van’s plans. Not really necessary, but it will add to a finished look when the glass lay-up is completed. The insert is just a little proud and will require a little filing to make it even with the foam. Also of note: The upper edge of the canopy foam adjacent to the upper edge of the canopy frame arms are to be cut down 1/8" below the edge of the arm. There is a small pocket visible in the photo below  - this area will be cut out anyway to 1/8" below the upper edge of the canopy arm … so no worries. After the foam material is removed and the area sanded, a mixture of epoxy resin and flox will fill this area and be immediately followed with the first lay-up of fiberglass cloth. The flox will provide a good bonding point for the lay-up.

The metal ring in now bonded onto the canopy frame. Went easy on the flox this round so as not to get any epoxy onto the bolt or washer. The remaining  small voids were filled later.

Van’s plans would have the builder doing the lay-up with the gas struts in place. Based on suggestions from other builders, the struts have been removed. I decided to make up a couple of foam block plugs covered with packaging tape to fill the void. These will be slathered with mold release so the fiberglass does not stick to them. I used the scraps from the C-1208 foam blocks and used two pieces to fill the void.

Longer foam block covered in tape is final length … aft foam block is being tested for a good fit.

Both foam block plugs in approximate position …. this should help hold the shape of the lay-up and keep epoxy away from the canopy deck.

Need to make the plugs for the right side later today and begin cutting out the patterns for the lay-up.

DOG Aviation Morns Passing Of Marty Dippel

As frequent readers of the DOG Aviation Blog know, rarely is there personal content within the Blog, but the recent passing of a long time friend warrants deviation. DOG Aviation morns the loss of longtime friend Marty Dippel.

Marty at AirVenture 2009.

I met Marty in 1970 through a mutual friend while attending a well known electronics school in Chicago. Marty married his loving wife Kathie and remained in Chicago. Although I moved away from Chicago, we keep in touch over the years. During the mid 80’s, we began to share our mutual aviation interest … and attended the EAA air show at Oshkosh. This began, what turned out to be, a much looked forward to annual pilgrimage to Oshkosh to attend AirVenture.

 

For many years Marty was my Oshkosh travel companion.  Prior to being diagnosed with stage four cancer (shortly after our 2011 pilgrimage to AirVenture), we had only missed attending the show a couple of times since the mid 80’s.

Marty admiring the wonderful crafstsmanship that went into this bird. After the show, we discovered this Skyraider won the grand champion award.

Marty was raised on a farm in Illinois and had a “salt of the earth quality”. His Father was a pilot, which rubbed off on Marty. So many single words describe Marty, but I’ll begin with brilliant. Marty had a keen intellect which was exhibited by his ability to design savvy electronic circuitry and manage large networks of Unix computer systems. Although Marty was easy going and soft spoken, he was very articulate and spoke with a deep soothing voice that was unassuming, yet exuded wisdom. Marty was very well rounded and could discuss most anything … electronics, shop tools, farming, airplanes, philosophy, classical music or high energy particle physics. He was a kind, gentle, honest and caring man, with a wonderful sense of humor. Simply put, he was the nicest guy you would ever want to meet.

When at Oshkosh, even a rainy day couldn't keep the smile off Marty's face.

Marty looked forward to every new DOG Aviation Blog posting so he could closely follow the progress of the RV-12 project and as he so eloquently said, “live vicariously through me”. I was ever so hopeful Marty would be able to contribute to the building of the DOG Aviation RV-12 … setting a rivet, drilling a hole … anything. Sadly, that was not to be because travel quickly became difficult, then unfeasible and lastly impossible.

Marty Dippel 1951-2015  We will miss you Marty.

Mixed Tasks Completed Prior To Canopy Fairing Lay-up

Prior to clearing off the workspaces and moving on to the fiberglass work for the canopy fairing, decided to smooth the edges of the polycarbonate rear window before stowing it away in the crate. As with the plexiglass canopy, the edges of the rear window were sanded down to a smooth edge by sanding with progressively finer grits. This required quite a bit of sanding … as the polycarbonate seems to be tougher to sand than the plexiglass canopy.

Beginning with 80 grit sandpaper, the edges of the rear window were quite smooth by the time 1000 grit paper was used.

Another task which I wanted to get out of the way was to prepare the rudder and vertical stabilizer fairings for the instillation of a metal backing strip which will be installed with epoxy fiberglass resin. The reason for this is because the flush rivets being used on the DOG Aviation RV-12 project will require the edges of the fiberglass to be countersunk. As such, I’m concerned that without the thin metal strips, the rivets will break down the now thin fiberglass as the rivet sets. Bonding thin strips of aluminum onto the inside edge of the fiberglass will allow the rivets to set on the metal and not allow them to pull through the thin fiberglass resulting from the machine countersinking. Metal strips were cut for bonding onto the fiberglass fairings. The plan is to bond the metal strips onto he fairings prior to drilling the holes into the fairings and machine countersinking them.

The metal strips will be bonded on the inside edge of the fairings then drilled so the rivet holes in the fairings can be machine countersunk for flush rivets without creating weakness in the fiberglass.

The DOG Aviation mail department has been receiving tips from fellow builders regarding the lay-up for the fiberglass canopy fairing. One tip received suggested removing the gas struts prior to doing the lay-up. I had been on the fence about this … but decided ultimately it was a good idea. Some have reported having a hard time opening the canopy so thought if necessary, it would be easy to remove the pivot bolts so the canopy can be lifted off the airplane.

Kurt from San Diego lending a hand holding the canopy as I remove the second gas strut in preparation for the fiberglass lay-up.

Preparations for the lay up involve bonding foam blocks onto the forward arms of the canopy frame. The blocks require trimming prior to instillation to conform to the shape of the canopy frame’s forward arms. After the foam blocks were trimmed to shape, I decided to make a small modification and add a metal tube to where the hole will be for the pivot bolt access. The tube will be bonded in place along with the fiberglass and provide a smooth tunnel for access to the pivot bolt and washer. Suggest using thin wall aluminum tubing so it can be shaped easily with a Dremel tool. Much of the foam block seen in the photo bellow will ultimately be removed during the shaping process.

Inserting the aluminum tubing being used to make a smooth tunnel for pivot bolt access.

The goodies for the lay-up consists of West Systems 105 epoxy resin and two hardeners … 205 fast hardener and 206 slow hardener. Although only slow hardener is required, fast hardener was also purchased and used to bond the foam blocks onto the canopy frame arms. It will also be used to bond the metal strips onto the previously mentioned fairings. In addition to the epoxy, flocked cotton fiber was purchased for use as an additive for structural bonding and glass bubbles to be used to create lightweight, easy sanding filler. A pump kit was also purchased which will pump out metered amounts resin and hardener.

The West Systems epoxy resin and hardeners, glass cloth, Dacron, mixing cups, cotton fiber, glass bubbles and the pumps for delivering metered amounts of epoxy resin and hardener.

A mixture of fast setting epoxy resin and cotton fiber the consistency of peanut butter was slathered onto the back of the foam blocks and they were pressed onto the forward canopy frame arms. During the next work session, after the epoxy has fully set, the foam blocks will be contoured prior to making the lay-up … this process will remove a large majority of the foam blocks.

Pressing a foam block onto the forward arm of the canopy frame. The foam block was slathered with a mixture of fast setting epoxy and cotton fiber.

Unfortunately, work will have to halt here for the rest of the week due to the loss of a close friend the next post will be dedicated to. Kurt flew out from San Diego and together we will be heading to Chicago for the services.