Category Archives: wings

After a long hiatus… tanks — a lot!

I’ve haven’t blogged anything in almost 9 months, but I’ve been very busy.  I spent a lot of time working on the my RV-12.  The condition inspection (more specifically, my updating the radio and adding ADS-B In/Out (a new GPS antenna and a new ADSB-In antenna) really kicked my butt.  It dragged on and on.

But through it all, I kept grinding away at the tanks.  It was really slow going.  Mostly I think that this was mostly mental.  I knew that I would have to break out the ProSeal and I kept prevaricating and didn’t get to the end.    Well, finally, I just decided it was time to dive in, so I did.  There aren’t a lot of pictures because my hands tended to be covered in grey, icky goo most of the time.  These pictures will cover many months work.

 

The fuel and drain fittings went in much more smoothly the second time through.  I was finally getting the hang of working with the sealant and got my riveting groove back after being out of practice for so long.  I got a nice squeeze out and made sure to thoroughly cover all the possible places it might leak.

For some reason, I was really looking forward to getting the fuel caps installed.  Maybe it’s just the nice contrast between the anodized red filler and the (not so) shiny aluminum.

Next, there is a lot of back riveting to do.  I tried masking off the areas around the stiffeners, but found that (1) it didn’t really help keep things clean and (2) it made it hard to form a nice bead of sealant.

I took the leading edge stands and built a little rotating adapter that I strapped to a low bench.  This proved very handy for getting a good angle for the riveting work.  This put the wings at a comfortable height and allowed me good access to both sides.

Another thing that proved handy was having small plywood backing boards.  These fit inside the ribs and made them straight and stiff for inserting whilst covered in sealant.  Also, if I needed to, I could give them a gentle tap with a dead blow hammer to get them to sink into place.  I highly recommend making a pair.  They just flip over to do the other tank.  One is long (for tapping) and the other sits inside the flange to give some strength when bolted together.

I also cut another piece of plywood cut slightly bigger than a rib.  This was useful for gently spreading the skins apart when I was sliding the ribs in.  It helped get the skin into the right shape and made just enough room to slide the next goopy rib into place.

 

The riveting was very messy.  I got everything together though and obsesses over covering each rivet head.  The J-stiffener was pretty hard to get in with enough sealant.  The instructions suggest that you can slide it in without touching the skin, but I found that I dragged off some of the sealant anyway.  I added a little more on the insertion side and it seemed to achieve good squeeze out.

 

I needed to fabricate the vent line.  One open end sits at the highest corner of the fuel tank (near the filler cap).  It comes back to a fitting on the inside rib (where the flare fitting is).  It was my first flare (I used my father-in-law’s flaring tool, so I didn’t have to buy one).   It came out very nice with no cracks.

 

In April, I was headed out to a conference near Portland, so I had to stop in at the mother ship.  It was a Friday, so the factory floor was empty, but I still got a nice tour and got to sit in the original 14A!  It was much roomier than I expected (and a bit taller).  It certainly reinvigorated my desire to get working again.

When I got back, I finally got around to fabricating the fuel floats.  I know some people put in capacitance senders, but this seemed so simple and basic that I didn’t want to stray from the plans.

   

Then it was time to seal up the rear baffle on the first tank.  I was pretty nervous.  I checked everything multiple times.  I had a lot of trouble, though, with the pull rivets.  I kept getting sealant in the puller which would then seize.  My trusty Stanley puller gave up the ghost, but I finally got everything pulled.

I took the first tank home to do the leak testing.  I put the balloon on and it seemed to hold air.  I took a dip in the pool and checked back a couple hours later and found that it was totally flat.  That weekend, I got some bubble juice to try to track down the leak.  It was at the balloon joint itself.

So off with the pink balloon and tube and on with a directly connected green balloon.  I added a little Gorilla tape to buffer the clamp so that it wouldn’t cut the rubber.  This one held for 24 hours.  One tank done!

So I did the second tank last weekend.  Brought it home.  Put a lucky green balloon on and….

There was a definite leak at the corner of tank inboard rib and the tank attach bracket.  Sigh!

It could be worse.  I think that I can vacuum in some thinned sealant to get a better seal (or maybe some LockTite).  If that fails, I can reach it by taking off the fuel level sender (yuck), but at least there is a hole that I can reach it through (or a tube attached to a syringe anyway).

In preparation for attaching the tanks and leading edges, I worked on finishing the leading edges.  I had skipped fitting the landing light lenses because it was cold (in NY!) when I last touched these.  It was a balmy 96 degrees F in the afternoon, so I was less worried about cracking.  The first lens has a small gap.  I hoped that I would get a better fit.  I’ll just use some silicon or something to make it watertight after final install.  The second on went on very nicely and I achieved a nice fit around the leading edge.  I changed my technique for the second one and drilled and clecoed the holes directly into the lens after the first rough cut (3/4″ margin).  This let me push harder on the lens from the inside and get that tighter fit I was trying to get.

So next steps are to patch the leaky corner in the second tank.  I’m hoping that it won’t be too hard to get to.  It takes a while though between iterations since I have to let the sealant cure a bit before testing.

Next, I will do the first rough assembly of the wings and fab the control rods.  There’s also a service bulletin that I need to get to that increases the doubler at one of the control mounts. I may even get the pitot mast mount installed.  I’ll wait to close up the bottom skins for a while so that i can get started on the fuselage.

 

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Redoing the aileron

I worked on the ailerons in my basement in NY during my “time of exile” between my Chicago job blowing up and starting my Texas job.  It was nice (except for the being out of work and worrying about the mortgage and food on the table and all that) to be able to work on the plane a bit every day. However, my work space was a bit cramped and I messed up the left aileron — badly.  I missed riveting some rivets on the nose skin!  I didn’t notice until both top and bottom skins were on. I tried to get my hand into the gap through the very small holes in the spar, but the bar and the rivet gun slipped and damaged the skin beyond salvage.

Well, I did all the deconstruction and figured out what pieces I could salvage.  I bought new skins (top/bottom/nose), a new spar, and new stiffeners.2017-04-08 10.32.22

I went back through the instructions and used a red check so I could distinguish from my first shot at left and right ailerons.  I was also able to complete the countersink that I had skipped whilst building these in my basement (since the countersink bit was in a hangar in Chicago, 800 miles away).

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I bought a new doubler.  It was cheap and easier than trying to get the old one off the spar.

There was a lot of trimming to rebuild the stiffeners.  It seemed like it would be less work than trying to get all 16 pieces off of the old skins.  It probably took as long, but I’m happier without having elongated holes in them.  I got a nice pile of aluminum shavings for my daughter to make into earrings though :-).  Unsurprisingly, I made the same mistake I did the first time through.  I did not trim the stiffeners to the right length.  I had to go back and cut them to the proper size so the “tails” did not lap over into the tail wedge.  Of course I discovered this after I had carefully smoothed the edges, so I had to give them another pass on the belt sander and the ScotchBrite wheel.

I had Friday off (the markets are closed on Good Friday, so it is a work holiday for me).  So of course I headed out to the hangar for some flying and building.  Got to work back to back on Friday/Saturday and really get some progress in.

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This is the point where I noticed that I did not cut 10.3mm tails on everything.  Sigh!

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I got the DRDT-2 set up again.  I opted not to build a dedicated table like I had in New York, but rather to clamp it directly to my work table.  The height worked out pretty well and I was able to get the nose, top, and bottom skins dimpled pretty easily.   2017-04-14 11.15.23

My hangar neighbor, John (with his faithful pal, Mia) is building a RANS S-21.  It is a much simpler kit with a pre-welded steel frame, poly fuel tanks, and fabric covered surfaces.   He only has about 250 hours into the build, but he’s ready to put the wings on!  He’ll be flying in six months or so   (This is why I bought the -12, so I could fly now!)

It’s been a while, but I fell back into the rhythm of building.  I got the parts scrubbed with Comet and primed (leaving the trailing edge clean for bonding).

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Friday night, I picked up some lumber at Lowe’s to make some stands for the DRDT-2.  I knew that if waited until the next time it was time to dimple, I wouldn’t remember to build some table stands.  I built a couple of nice 2’x2’x7″ boxes with carpet tops.  They fit nicely on the EAA tables.

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My buddy Carver was back from Sun ‘n Fun eager to help.  He finally decided that he’ll start on his own RV-14A next year.  He wants to practice on mine!  I showed him how to back rivet and got him started on the skin stiffeners while I prepped the nose skin and spar.

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We got the nose skin half riveted to the nose ribs and called it a day.  Here, Carver is squeezing his first rivets with the 4″ no-hole yoke.  They came out very clean.

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We loosely clecoed the spar in place just to keep the metal from sitting in a bent position all week.   The redo is coming out very clean!

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It will probably take another full day to complete the aileron (plus a second day to let the trailing edge set up).  I’m looking forward to getting started on the tanks (you can see the parts sitting on the bottom of the bench taunting me!).

Meanwhile, I’m still working on the RV-12.  I’m feeling a lot more confident flying it.  The comm/intercom has some issues.  I’m planning on swapping the SL40 out for a new Garmin GTR-200.  All the reviews say that the intercom is really nice and it should clean up the squelch problems I’m having.

Tank time!

I headed down to the shop a little early this Saturday.  There was a front coming through in the afternoon and I wanted to get some more flying time in with the -12.  My neighbor was in his hangar banging away at his Rans, so I invited him along for the ride.  Just up for 45 minutes or so.  There was a scattered, low cloud deck at 1700′, so I didn’t go very far.  Some practice with the navigation system and playing around with turns.

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I still had a little deconstruction work to do on the bad aileron.  I got the thing pretty much apart and salvaged the nose ribs and end ribs.  After breaking off the manufactured heads, I still had to remove some of the shop heads.  I didn’t want to drive them through (which might bend the flanges here), so I just used a pair of pliers to rotate them out. The replacement parts will be here Thursday, so I can start the rebuild then.

When I packed up the shop, I roughly clecoed the ribs into the fuel tanks.  This kept the pieces together and kept the skins from getting banged up.  I wrapped the whole thing in moving blankets and slipped it into the spar crate.  Worked wonders for two moves!

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I had skipped the fuel tank section because I wanted to do the work when the weather was better. Not fun using fuel tank sealant, and really not fun using it in very cold weather!  So, first I started looking for parts.  The tanks have a surprisingly large number of parts!

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I quickly found and sorted the main ribs.  The inner ribs have a large hole in the bottom so that fuel can run between the ribs.  I’ll probably put in a flapper door that helps keep the fuel inboard when maneuvering.  The outside ribs, of course, don’t have the holes. I quickly found the brackets and the stiffeners, but it took a while to dig out the flanges and fittings (hidden in a small brown paper bag labeled “Fuel Fittings”).  There was one part, though, that eluded me for almost an hour.  I couldn’t find the T1005A stiffener and clips.  I checked all over the hangar.  Finally, just as I was about to give up, I found it in the parts cabinet.  It’s an bent L, only about 1 foot long.  It had slipped to the back of the shelf and was mostly hidden.  I think I have all the parts now!

My buddy Carver is coming over next week to help (He’s at Sun ‘n Fun this week looking at planes!).  It will be nice to have more hands to do the parts prep.  Just gotta remember not to prime anything!

Flap Therapy

 

I’m looking for a new job.  The old one in Chicago just didn’t work out, so my employer and I have parted ways. For now, the majority of the project will stay in Illinois until I figure out where I’ll be working next. I did keep some parts to work on at my NY home, so at least I can make a little progress!

So, I got started on the flaps.  I figured that they would be pretty easy to build in my basement shop.

I made the brackets earlier.  They were pretty easy to make using my table saw and band saw.

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Like most sections, this one starts with lots of parts preparation.  There’s a little fluting to do on the nose ribs (made harder by the fact that my fluting pliers are still in Illinois) and some burnishing of gaps to prevent faceting, but the annoying part is cutting a bunch of tabs off the flap ribs.  They’re easy to identify (no problem with Left and Right parts) since the tab has no hole.   I cut these off using metal snips and then used a file to carefully trim the edge down.  The snips did cause the edge to bend a bit, so I had to carefully straighten them with some smooth nosed pliers.

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Similarly, each of these rounded cuts caused the ends to “pucker” out a little bit.  It’s not noticeable until you look carefully.  But as I applied the same smooth pliers to each, I could feel the pucker straighten out.  Then, there’s lots of deburring.  The edges and holes on all these ribs were a little rough.  Lots of hand work with sandpaper and files to get the edges prepped.   I don’t have pictures here of the hinge plates and doublers, but they too required a lot of hand work to smooth out cut marks.

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Then, you assemble the flap skeletons.  This is one of my favorite parts of building… when a “real” airplane part suddenly starts to emerge from the pile of small parts!

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Here’s a close up of the inboard and outboard rib assemblies.  At first, I though that the inboard one was for the inboard most position, and the outboard one was for the outboard most rib.  No….  They work together to hold a rod that will eventually connect to the flap control system.  A bit of squinting at the diagram made this all clear.

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The joggled hinge brackets line up very nicely.  There are holes in just one of the joggled parts.  Later, when everything is lined up, I’ll match drill and rivet them together.

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I’m working on both flaps at the same time to help make sure that I get the right parts in the right assembly!  The two are mirror images, so it helps to see both at the same time.

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Next, you cleco together the skeleton with the skins.  It takes a bit of finesse to get the nose skin in place.  It has to be fitted over the flap hinge brackets and then worked around the nose ribs.  Two of the nose rib holes are not pre-drilled.  We’ll get them in the next step.  I just kept working the clecos around the edge and eventually got the whole thing put together.

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I match drilled the “missing” holes in the nose ribs pretty quickly.  The only real problem I have is that I only have a small compressor at home.  The air drill quickly runs through all my air, so I have to wait occasionally for the compressor to catch up.

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You need to be careful drilling the trailing edge.  The instructions make it quite clear that you must drill perpendicular to the cord line not perpendicular to the edge.  It’s a 84 degree angle.  I used to have a block cut to that angle (from previous trailing edge work), but it is lost somewhere either in Illinois or in the scrap heap.  So, I just downloaded a paper protractor and taped it to a square.  This provided enough guidance to final drill without enlarging any of the holes.

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So, here’s two flaps!  Of course, now the real work begins.  I have to deburr, dimple, and prime all the parts (and match drill the hinge brackets) before putting this all back together.

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Lots of work upcoming.  The big one, of course, is to get a new job!  I have some leads and have done some interviews.  I’m hoping to hear soon what’s up with that.

I have enough parts to work on for the next month or so (flaps and ailerons) and may bring back the tanks when I go back out to Chicago to move out of my apartment.

I’m hoping the next couple weeks will bring some better direction.

Rivet right leading edge…

Lots and lots of rivets! After all the setup work last week, it was finally time to get down to business and get riveting.  The right leading edge was sitting in the cradle, just begging to be riveted when I had to call it quits last week.  You start with the first two rivets on each rib and start working your way down.  The top two rivets were squeezed as were the rivets through the splice rib (though I banged some of them with the gun to get a smoother fit).

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I’m getting pickier about my rivets particularly since this is a very visible surface.  I ended up having to redo 7 or 8 rivets — clearly, my skills have atrophied.  At least I was still pretty good at getting rivets out!  This one came out very cleanly.

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I use a wide head on the rivet gun instead of the floating mushroom head I started with.  I got the idea from Carl and Rafael’s RV14 site.  They previously built other RV’s and so most of their advice is pretty good.  Here, I found that it is much easier to control the wide head and hold it flush.  The packing tape idea is a pretty good one too!  There is very little marring around the rivets and the heads are very flush to the touch.  It gets a little harder right on the nose, but even those came out great!

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On Saturday, I got the work about half done (in a half day — I’m trying to spend some time on the house getting it ready for the sale).

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I also did a test fit of the landing light bracket.  It definitely has a top side and a bottom side.  The plans do not spell this out very well, but if you look closely at the illustration, you can see which was is up (Hint, the wider side goes up toward the stiffener).

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As I got down to the last three or four rivets in the nose, I had to pull the leading edge out of the stand and reach in.  This was pretty awkward.  I found that my new round tungsten bucking bar was really handy.  It is a little shorter than my rectangular bar and about .25 pounds heavier.  It really sets the rivets nicely.

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I still have a couple of rows to do on the other side (and the landing light bracket), but I had to cut Sunday’s session short because I was taking my daughter out to practice for her driving test.  I also got a call to pick up a picture at Michaels.  A massive squall line moved through while I was in the store, inundating the parking lot.  As the line moved north, we got blue skies and a nice double rainbow.

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I also got a package in the mail… I saw a classified ad for a Nomex flight suit for only $30.  This is a used Air Force one.  It has velcro for subdued patches and the like.  I’m still a couple of years away from first flight, but this was a bargain.

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Hmmm…. perhaps I can dust off my old Space Command patches from my time in the 1000 Satellite Operations Group!  Or maybe StarFleet Command 🙂

 

 

Powder coating and nutplates, nutplates, nutplates

Well, I tried some powder coating.  The experiment was a qualified success.  I was able to get reasonable and smooth coats on some pieces.  I think that I will be able to use this process for visible pieces in the fuselage and cockpit.  Here’s my first test on a piece of scrap.  This is the matte black powder.  My coverage wasn’t quite perfect, but it was clear that the electrostatic attraction thing really works.  The lighting in my booth wasn’t the best, which I think was a bigger problem.

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Then I tried the W-00018 backing plates.  The coverage was again a little thin.  I think that I can make it better (or if I used a second coat).  The powder coat ground was clipped to the crossbar and I was using our old toaster over as a curing oven.

In any case, I ended up giving them a light coat for matte black Rustoleum to make them match the lighting bay color.

I also sprayed the landing light brackets and the inspection hatch doubler while I was at it.   Then I was finally ready to tackle all the nutplates called out on page 17-04!

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For the backing plates, light brackets, and hatch doublers, I used NAS1097 rivets with the small head and 3/32″ body.  These are not structural, and only keep the nutplates from rotating, so the very thin countersink is not a problem.  This is much easier than dimpling the nutplates themselves and it keeps from wildly distorting the aluminum pieces with so many dimples so close together.  I bolted my squeezer to my work table so that I could concentrate on holding the parts steady.

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The splice plates had 18 nutplates each!

I reassembled the left leading edge.  It was a little tougher to get everything to fit with the skins dimpled.  I had to use a punch pin to align one of the top holes and then cleco away.

I didn’t get much else done (heading out for an evening date with the wife.. gotta keep her happy after spending all day with my aluminum girlfriend!).  I did manage to get the access hatch done.  I think I like the flat black paint on the doubler instead of the primer.  I’ll likely do the other access hatches this way.

Next up, I’ll prep and prime the ribs for the right side leading edge (a bit less work since there is no access hatch nor stall warning vane).  Also have to do all the dimpling for the right skin and J-stiffener.  After that, it will be a flurry of riveting.

Working on the leading edges

 

With the top skins on the wings, it’s time to get down to working on the leading edges.  These seem likely to be the last parts I’ll finish before moving the project to Illinois.  Then, the whole thing will likely sit on the shelf until we move out in July.

Section 17 starts with a lot of part prep.  I built the cradle pieces and trimmed the nose ribs while I was waiting for bucking help on the wing skins, so it was time to do some initial fitting and match drilling.  I first sorted the ribs to make sure I had the correct ones for each side (and to make sure I had trimmed the right ones earlier).  I also had to trim the J-channel pieces.  I finally figured out how I had the reversed J-channel pieces for the wing top skin… it wasn’t reversed, it was a piece for the bottom skin!  Sigh.  Alas, I also discovered that I had cut my short W-00009B pieces (first page of the wing instructions) from the wrong piece of stock.  So, I realized that I needed to order two new pieces of J-channel (luckily I won’t need them until I get started on the tanks this July).

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You need to separate this splice strip from the tank skins.  It get riveted to the leading edge and then we use nutplates to screw the tank skin down.  The instructions suggest using a cutoff wheel to do this.  I had visions of cutting off my fingers and of gouging the tank skins, so I opted for something simpler.  This mini-hack worked great.

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Lots of dimpling on the ribs.  There is one more hole that gets match drilled later that will also need to be dimpled.  These dimpling pliers were a great investment.  I use them all the time for dimpling ribs and the edges of skins.  A lot easier to use than my squeezer or my DRDT-2.2015-12-05 11.55.27

On the left leading edge, you have to cut out a slot for the stall warning vane.  I considered just skipping it because I’m adding an angle of attack pitot tube.  I decided to leave it in because (1) it would be a real pain to add after closing up the skins and (2) the A-O-A has to be calibrated before it gives you good feedback.  Since my very first flight is all about calibration, it will be a good idea to have a dirt simple stall warning.  So, I cut the hole out.  Note the big holes on the ends.  Those are a #10 hole.  I didn’t have a #10 bit.  So I ordered a whole set of cheap Chinese bits from size #1 to size #60.  I’m sure they’re not real great quality, but there are a lot of these “drill one hole” parts of the instructions.  I have quality bits for the common sizes, but now I won’t have to wait a week each time I fail to notice yet another weird size bit.

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The clippers did a reasonable job clearing out the hole.  Then a lot of careful filing finished it off.

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Not too bad!

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You need to fabricate the J-stiffeners.  Lots (and lots) of holes to drill.  This is a traditional “blue-lining” job.  You drill one end hole, draw a blue sharpie line down the middle of the flange and then carefully drill and cleco your way across the stiffener.  Then you have to deburr everything….

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…. and dimple everything.  Luckily, this fit on to the DRDT-2.

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Then you need to dimple the skins… There are approximately 3 bazillion holes to dimple (and a dozen or so to skip).   Got the left skin done.  The right skin is waiting in the wings still partially assembled to avoid intermixing the parts.

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There are still more parts to prep.  Here are the brackets for the landing lights.  They were pretty rough and needed a file to smooth them out.  They get dimpled (they are deep enough to countersink, but I’m not going to try to second guess the instructions). They need to be painted flat black to help hide the landing light.  I was going to spray paint them, but then I saw a presentation on powder coating.  I’m going to try that next week.

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In preparation of powder coating the brackets (and in painting the ribs), I decided to make a mini painting booth.  This one is built out of a Home Depot wardrobe box.  It has a 20″x20″ filter wired in the back to help keep overspray under control.  The metal arm will work great for adding the ground wire for powder coating.

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The video I watch on surface prep and powder coating suggested that you wash the surface with Ajax or Comet.  The scotchbrite pad scuffs it up, but the Comet helps remove any grease and also removes any light oxide build up.  When you start, water beads on the surface so you know there is nothing for the primer to grip.

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After a bit of scrubbing, the surface is very lightly scuffed, but still Al-clad for maximum corrosion protection.  And it will really hold the primer (and black paint for the light bay).

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So now, I’ve got one leading edge ready for black paint and reassembly!

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Next up, I’ll paint the bay, prime the ribs (and paint the two in the light bay black), try powder coating the light brackets, and start the reassembly.