Tag Archives: priming

Sneaking out at night to work on the plane…

Tuesday night is Choir night for my wife…  It used to be my volunteer fire department but the move to Chicago forced me to resign.  So, with the wife out of the house, there was time to sneak out to visit the aluminum girlfriend!

I only had 2 or 3 hours to work, and luckily I had a task that wasn’t too loud for working at night.  The leading edge ribs and splice strips needed priming and painting.  I’ve been trying a new method of prepping surfaces for priming.  I’ve been scrubbing with red scotchbrite and Comet cleanser.  This really leaves a nice, grease free surface.  It is a bit more of a hassle since I don’t have running water in the shop.  I have a 5 gallon Jerry can of water and some tubs.  I also got a simple sprayer from the Home Depot aviation department that I fill with water for rinsing.   I got some really nice, clean surfaces.  I had to blow off some rinse water with a heat gun and finish with a lint free cloth though.  They came out pretty nice!

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One of the nice things about the RV14 kit is that Vans put a lot of work into thinking about the bits and pieces outside the airframe that need to go in.  Wiring harnesses, antenna mount points, standard panels, etc…  Here, they’ve pre-cut the holes for a landing light lens and provide a standard mounting bracket (but no light!).  They suggest painting the cove matte black or gloss white.  It’s easy to do now.  So I painted the bay….

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and the two ribs that line the bay.  They look shiny here, but the paint hasn’t flashed yet.  I did the priming and painting in my new “low end” paint booth.  The fan provided a gentle suction that kept the overspray in the booth (trapped in the air filter I wired in).

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The backing plates and mount brackets also need to be black, but I’m going to try powder coating those.  I’ll of course try it on scrap first, but I’m hopeful that it comes out well.  I’ll likely powder coat the access hatch double as well.

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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.

 

So many dimples! One wing ready for riveting!

Well, I got to work finishing the top wing skins (Section 16-02).  It took a while to strip off the blue plastic (14 ribs x 2 wings plus 3 horizontal stripes).  I finally got that done and finished the countersinks for the wing walks.  My wife came by for lunch (and to keep me from spending all day with the plane — she’s a bit jealous and calls the plane, my “mistress“).  She took a picture so the FAA will know that it was me sweating over these skins in the garage.

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Doing the countersinks for the wing walk doublers… the instructions caution to make sure these don’t go too deep.  The skin is right on the borderline of too thin to countersink, but it works better to deal with the top skin/doubler/rib sandwich.

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Next, I had to pull the skins off to make a scarf joint along the forward edge of the skins.  I’m starting with the right wing.  It’s easier to leave the skins on the rib skeleton as I have no better place to store them.

I found the illustration very confusing.  The shape on the bottom does not nest with the shape on the top.  It took me a while, but I finally figured out that they just wanted the two skins to lay flat on the spar.  Once I saw that, it was easier to figure out how to shape the corner.

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The inner top skin sits underneath the outer top skin.  The gap between the spar and outer top skin is too big if you just let it overlap.  So, we file and sand and polish a bit off the inner skin and then remove a matching amount off the outer skin and try for a flat joint.

I clecoed my skins to the tables to get them lined up and then filed and sanded the corners.  I used my bastard file since you have to carefully remove a surprising large amount of material.  Still had to be careful.  Several bloggers reported removing too much and having damaged or rounded corners.  I used some sandpaper and a paint stir stick to finish it off.

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The joint is a lot flatter after the adding the scarf — not sure this picture does it justice.

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There is a lot of dimpling to do on the skins.  The inner skin has almost 250 dimples to make (in addition to the 70-80 countersinks).  The outer skin has over 450!  My son dropped by (for lunch) and I enlisted his help in doing the dimpling on the DRDT-2.  It can reach all the dimples and it made nice crisp ones.

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The blue X’s are reminders not to dimple the wing tip attach holes quite yet.

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The two foot throat can reach all the way to the middle of the skin.  2015-08-09 15.25.18

With the dimpling done, it was time to prime the skins.  I ran a line of primer over the rivet lines and filled in with a light coat of primer.  You can see the large outer skin, the smaller inner skin, and the two wing walk doublers (those are primed on both sides).

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I also needed to finish the J-stiffeners that go down the middle of the wing.  These were match drilled in the very first wing task a few months ago.  I stripped off the blue plastic, and ran a deburring bit through the holes.  Then they got shot with some primer.  They’re not in the wing yet, but that should not take long on the next build day.

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So, the wing is just about ready to rivet.  With the dimples in place, the wing really feels solid.  It’s amazing how much just dimpling adds to the sheer resistance for the skins.  They really lock in tight!2015-08-09 17.44.16

I also had one last minute task on the right wing.  One of my rib flange holes was a bit enlarged when I double clutched the dimpler.  I reamed this out to 1/8″ (hence the copper cleco) and marked it for an “oops” rivet.  The tape goes over the cleco depressor, so I’ll be sure to remember to swap in the NAS 1097 rivet for this one hole.  The head is a normal 3/32″ size, so it won’t be noticeable.

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Next, I have to slide the J-stiffeners into the right wing and then do all the dimple and prep work for the left wing skins.  Then, it will just be a lot of riveting to finish this section.

Slow cooked ribs…

I needed to finish prepping the remaining 18 wing ribs.

The weather was much improved from a couple weeks ago.  The shop was a whole 45 degrees F when I opened it up with no snow outside.  It really improved the ventilation for the priming.

20 or so minutes per rib to

  1. Uncleco from the spar where I had them sorted
  2. Mark and remove the spar bolts
  3. Check the sizes and locations of the snap bushings
  4. Mark the location of the bushing hole that wasn’t pre-drilled
  5. Drill a pilot hole for the snap bushing
  6. Step drill the 1 to 3 bushing holes
  7. Deburr the holes
  8. Deburr the rear-most lightening hole (too big to get with the Scotch-brite sanding wheel)
  9. Hand deburr the little slots in the flanges
  10. File the rough flange edges to something smoother
  11. Run the flanges through the big Scotch-brite wheel
  12. Shoot it with primer in the paint booth
  13. Mark the rib with it’s location
  14. Hang it up

That’s all I did… all day long.

I caught my knuckles on the spar a couple times trying to break the spar bolts loose.  There’s a sharp edge from the big double plate that just wants to grab you.  My father-in-law expressed no sympathy and simply suggested that I paint the whole thing blood red.  I was actually thinking about that as a color scheme.  Here’s a very nice paint job that I like!

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But in the end… All the ribs are ready for the next steps where I’ll install some snap bushings, rivet the flap attach and torque tube assemblies, match drill the bolt holes for the ribs, and install the ribs (rivets and blots).  The instructions call for doing the match drill step earlier, but I didn’t have the right sized socket to pull the bolts.  Easy enough to do in this step.  I should finish section 14 in the next build session and my wings will start to look like real wings!

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Unusual attitudes…

I’m getting very close to the end of the tail cone build… I started it just one month ago, but I’ve put a lot of hours into it!

The last steps are to mount the top sides and top skin.  This gets hard because the fuselage is so big at this point and it’s getting hard to reach everything.

I got a bit of build time in on New Year’s day… a great way to start the year!  The shop was a little cold though!

 

I had enough time in the afternoon to deburr, dimple, and prime/paint the side skins.

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The piece is very big and some of the reaches are hard to get to with the curve and the j-channel.  I used my reduced diameter dimple die and worked carefully around the channel.  It was awkward, but I was able to do all of it without a helper.  With the pieces dimpled, it was time to prime and paint.

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I came back in on Saturday for a full build day.  I had some fix up work to do before embarking on the skin riveting.  I opted for flush screws for the rear cover plates.  I didn’t read ahead in the instructions carefully at the time and neglected to see that I needed some different nut plates and screws to do this.  I ordered some from Van’s (their nut plates are cheaper than the other suppliers) right before Christmas.  They got here on the Friday after New Year’s.  I also needed some new pop-rivets for the rudder guides (I put the rudder cables in backwards… an easy fix at this point!).  So I went about installing those pieces.  I was able to get all 16 nut plates with my longeron yoke.

I finished the edges on the cover plates and marked them (on the inside and the blue plastic).  They are not symmetrical!  There is a left and a right and a top and a bottom.  Be very careful if you decide to do the flush option as you get one chance to dimple correctly!

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With the catchup work done, it was time to attach the top side skins.  These skins are almost 8 feet long and really very awkward.  However, once I got one cleco in, the rest of the holes just lined right up.  I really like these kits!

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I contemplated how to do the riveting here.  I know that one builder (with a helper) back riveted the whole thing.  I didn’t think I could convince my normal helpers (wife/son/daughter) to come out in the cold, so that was out.  I thought about moving the assembly to the ground and to then reach in, but that didn’t seem workable (and I didn’t think I could safely lower the tail cone to the ground by myself).  I ended up tipping the fuselage on it’s side.  This gave me plenty of access to all the rivets.   This puts the fuselage in a unusual attitude (a knife edge turn perhaps!).

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I was able to reach and buck all the rivets with ease.  I had pre-marked the spots that got 3-4 and 3-4.5 rivets so I would remember to switch sizes.  It went so well  on the left skin, that I spun the fuselage around and started the right skin!

My trusty bag of AN426 3-3.5 rivets that seemed impossibly full when I started finally gave up the ghost and ripped.  I transferred the remaining rivets to a small bin.  The wing uses mostly 3-3 rivets.  It’s like saying goodbye to an old friend!

I almost got all those in, but it was getting late and it was snowing.

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So I just did a quick back rivet job on the top skin and called it a night.  The job was a bit too quick as it turned out.  The j-stiffener didn’t seem right when I riveted it in place.  It didn’t fit well and didn’t turn out flush.

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So I snapped another FAA-selfie and called it a night…

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The j-stiffener still bothered me and I figured I would work it out the next day… …and I did.  I sat bolt upright in bed at about 7am and realized that I had forgotten to dimple the stiffener.  That explained everything.   It also meant that I had 20 some odd rivets to drill out.  All but one came out nicely.  I stayed very centered on most of the heads and they snapped right off.  You can see the neatly centered holes and the rivet stems with a nice clean edge.

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One rivet didn’t come out so well.  And I cut my finger tip trying to swipe away some aluminum shavings (I forgot to make our family’s daily invocation – “We don’t have any time for a trip to the emergency room!”)

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Not a big deal.  I clecoed it all back together (after dimpling this time!) and reamed the hole out to 1/8″.  Then I put in an “oops” rivet.  The head is gold instead of silver, but that will be hidden by paint.  Almost indistinguishable, even on the inside.

With the top (re-) done, I clecoed it in place.   I also built a big (8′ x 3′) shelf to hold the tail cone when it’s done.  It fits nicely above the crate holding the wing parts.  I’m very close to getting a new trophy on the wall!

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The first revision of the instructions left out a step to rivet the top skin stiffener to the forward bulkhead.  It is in the revisions (and in the gotcha’s list).  Even if forgotten, it is easy to fix later. I was able to reach inside and squeeze 3 4-4 rivets in the holes to finish it off.

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While I was in there, I reattached the static line to the static port.  It had previously pulled out of the hole and I reapplied the recommended gasket compound.  However, it pulled out again.  Sigh.  I’ll try JB-Weld and see if that holds better.

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I think I need a helper to rivet the top-most skin on.  The reaches are very long otherwise.  I might be able to make it, but it will be so much easier with some help.  So I went home and cooked a nice dinner for the family (teriyaki pork medallions, pickled vegetables, quinoa, and red wine poached pears.  Very tasty!).

Turn the page…

Apologies to Bob Seger, but sometimes I feel that I get stuck on a single page for days at a time.  I can hardly wait to turn the page, as it were.

This time, the page is 10-14.

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It took some work to get to the page, but then it seemed like I was just stuck there.

As of the last writing, I was working on the bulkheads and looking ahead to this page.  It seemed so easy!  It turned out to be a lot of work!

The parts are getting very large.  This means it takes proportionately longer to deburr, dimple, and prime things.

First up was the bottom skin.

I pulled the blue plastic off (very hard with the cold temps).  I had to wipe off some adhesive like crud from where I pulled riveting strips off the bottom with acetone.

I deburred the edges (the inner edge is a kind of built in j-channel) with file and sandpaper and scotchbrite. Then I started dimpling… and dimpling… and dimpling!

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I got a “selfie” while I was at it so the FAA will know that it was me freezing my ass off building this thing.

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I primed and then painted the inside skin pan Rustoleum Granite grey.  My thinking is that the interior is “public” space.  It will be viewable, stuff will knock around in it.  The primer isn’t super durable (and not really a final finish), so I topped it with a nice neutral grey.  It looks nice!

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Van’s recommends using two sawhorses, but I found it easier to work with one sawhorse and one table end.  I could clamp the bellcrank rib box to the sawhorse and make it very stable.

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I decided to back rivet the bottom skin.  I had a two pound back rivet bucking bar that I was planning on using for the wing skins.  It worked really great here.

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You can get nearly every rivet this way except for a few that are right up against the bulkheads.  I only had to buck four rivets.

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The riveting went really fast when my son stopped by the shop to give me a hand  He would pull a cleco, drop in a rivet, and place the bucking bar.  Then I would give the rivet a tap.  Super-easy.

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I came back the next morning, bucked the four missing rivets and started on page 10-14….

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There are SO many rivet holes everywhere!  Four stiffenners, two longerons, and matching holes in the left and right skins!

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The side skins have a lot of detail bits to get to.  Here, I’m going at the rudder cable pass through opening with a small file.

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Finally, the right skin get’s a coat of granite grey to finish it.

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After this skin dried, I hung it on the bottom skin. Then I had to start all over again with the left skin!  I was much faster the second time around though.

Over the weekend, I was going through the plans errata at VansAirForce and noticed that the instructions forget to mention to rivet the bellcrank ribs to the F-01407 bulkhead.  Sure enough, I hadn’t done it.  I flipped the rear fuselage over and was able to squeeze four of the six rivets, but had to use my offset set to drive the last two.  The shop towel helped protect the finish from the bucking bar and the blue painters tape did the same for the rivet set.

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The stiffeners and longerons go on in this step.  The spar is too heavy a gauge to dimple, so it has to be countersunk.  There are 176 holes or so.  I had a lot of magic pixie dust!

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The stiffeners and longerons are supposed to “slide” in… ha ha ha. I ended up having to put them on before clecoing the skin in place.

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I eventually managed to get everything in place and flipped it right side up on my tables!

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It looks practically ready to rivet!  It’s not… still a couple of pages to go before that happens, but at least I can finally turn the page on 10-14!

So page 10-15 just has you cut some tabs off of the aft bottom skin.  It is actually a lot of work because you have to rebuild a smooth edge from the rough saw cut.  I ended up clamping it loosely to my bench and filing the edge down to a smooth finish (and then doing a final pass on the scotchbrite wheel).  I gave it a quick coat of primer and granite grey and re-clamped it to the bench to rivet the rearmost bulkhead.

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The most exciting news was that I took the last few items out of the empennage case.  I needed the space to walk around the table and wanted to tip it out of the way.  So I took out the top skins  and a couple miscellaneous parts and tipped the box on it’s side.  I must really be getting to the end of this kit!

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I had a hard time getting the aft rear skin and bulkheads in clecoed in place.  I ended up pulling the skins off and rejiggering the hole mess.  Eventually though everything was square and then the clecos slid right in the way they’re supposed to.  My son stopped by to help rivet, but we spend about an hour just getting the clecos ready.

We were able to squeeze the top row.  It went really fast because we could squeeze most of the rivets away from the bulkheads.  My son would pull the clecos and set up a rivet for the easy ones. I got the reset with my tungsten bucking bar and mushroom set.

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It was getting late, so I didn’t have much time (my son had gone home to sit down and warm up since it was back to a one person riveting operation).  I got the top half of bulkhead rivets done down to the A stiffener.  I’ll get the bottom half tomorrow… I’ll probably need some help to get the curved bottom parts though.  The skins there do not lay very flat.  I broken them as Van’s suggests, but they really need a lot more bend than I gave them (particularly  in the aft section).  I’ll probably try to soft tap them with my rivet gun to set a curve.

 

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Got a few hundred rivets in today.  Should get about three hundred more tomorrow!  Then the top skins go on with a dozen nut plates and the wiring harnesses get routed (the harnesses are already in place to get them to run through the stiffener channels but have to be finalized in a couple of pages).

Closing in on a new trophy if I can just get off page 10-19 🙂

Bulkheads everywhere….

Even with mass this morning and fixing the Christmas lights, I got to the shop by 1:30 for about 5 hours of work on the bulkheads.

There are five bulkheads.  I riveted the aft-most one yesterday and deburred and primed the next two  Those came together pretty quickly.  With lots of cold 1/8″ rivets, it was easier to hand squeeze than to use the pneumatic squeezer (better control and more oomph by hand!).

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I clamped my hand squeezer to the table which made the riveting much easier than holding an unweildy bulkhead and a rivet and a squeezer all at once.  It also made it a lot easier to get a good push on the arm and make best use of its mechanical advantage.

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The rear three bulkheads take up only 20″ of the fuselage!  They have bulky straps to hold the vertical and horizontal stabilizers in place.

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The next steps seemed so simple…  The 2 forward bulkheads only have a few rivets and no thick aluminum straps to mount.  However, they are very large (compared to the other bulkheads), are made in two pieces, and have many, many nooks and crannies to deburr.  I filed the worst parts of the outside with a fine file, hit the many lightening and system holes with sandpaper and scotchbrite, and sanded around each of the approximately 10,000 flange tabs.  Then I finished the accessible edges on the scotchbrite wheel.  I used almost (but not quite) all my remaining primer priming the bulkhead parts.  Not too many rivets to do and the squeezer was still set up, so I thought I would bang together the last two bulkheads.  The first one went together very quickly (only 5 rivets as you leave the top 3 open for later riveting).  The second one has ten rivets (an extra two hold the rudder cable bracket to the bulkhead).   On my very last rivet, the squeezer apparently shifted so I got a smile rivet to drill out next time.

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So, the bulkheads are done for now.

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The next steps are to deburr and prime the bellcrank ribs and one more, thankfully small, bulkhead.  Then the bottom skin goes on and it starts to look like a real airplane body.