Priming More Skins

Today was priming day. I shot the primer on 4 more skins (3 left to do) and the small parts that I had prepped yesterday.
Nothing eventful happened except for trying a new spray gun. I bought the HVLP spray gun kit from Harbor Freight that contains a gravity fed big gun as well as the downsized version of it called detail gun. Until now I had used the detailer exclusively but for the skins I wanted something to shoot the large areas quicker.
The big gun works great (I used the small valve), sprays the paint quickly and evenly but uses significantly more air than the detailer. So my compressor was not really happy about this :-).
Here are the results:

Bulkhead Done, almost

I was just about to finish the bulkhead by riveting the 8 nut plates into place when I was realizing despite my thorough inventory I did when the kit arrived I must have overlooked a missing K1000-3 nut plate. I couldn't believe it and so I was counting about 5 times .... 8 places for nut plates and, yes, the plans indicate all are K1000-3 - a look in my sorter showed 7 nut plates for the K1000-3 and none in adjacent drawers, so nothing got mixed up. I finally accepted it and realized that it wasn't that bad as it wouldn't hold me back. Until I finally install the Stabilator on the tail cone I can still reach the place to rivet the missing nut plate in place. Order to Van's along with 3 tie down eyebolts went out right away and I saw that they already shipped it, so it should arrive some time next week.
Well, I riveted in place what I could to almost finish the bulkhead.



Then I went on to install the side plates and the bearings for the Stabilator. After the squeeze training I had yesterday, doing 12 more was a piece of cake :-)



This job went pretty fast and so I decided to look ahead again and see what else I could do to add to the upcoming priming spree. There were a few parts that just needed deburring - next to the attach point of the vertical stabilizer which needed some final drilling and dimpling.



It really didn't take long and with the help of the big and small Scotchbrite wheels it was soon turned into this:



Finally I went outside of the nice cool A/C of my shop to work on prepping some more skins to get them ready for priming, along with the small parts that I had just deburred. With the monsoons sweeping in the afternoons the humidity is too high for spraying so I hope I can do that tomorrow morning and have the day time for drying it.
I got 4 more skins done, only 3 more to go but this will have to wait for the next batch. Spraying those skins really takes time.

Squeeze It, Baby!

I was working on the bulkhead and it was supposed to get riveted to the doubler that reinforces it, along with the skid bracket and some other brackets that I don't know what they are supposed to do yet. Almost all of the rivets were AD4 squeeze rivets and I can tell you that I feel it in my arm ;-).
Clecoing the parts together was the fun part!



Here we are about 1.5 hours later and almost done with the outer rivets (the doubler and bulkhead were supposed to get riveted first).



Done! Except for the nutplates which I will install after fixing some thin primer coating on the back side. I don't want to spray on the nutplates, so I do this now and finish the riveting later. I can definitely take a break after squeezing for two hours straight.

The manuals matched mostly what I was doing except for 4 rivets that I felt were too short using the ones indicated in the manual. I have marked them and I used AD4-5 instead of the suggested AD4-4. I will probably be 4 pieces short of AD4-5 when I get to be asked to use them eventually... :-)

10-03 & the Skid Bracket

There was something in the back of my head that I just couldn't resolve and it didn't let me rest, so I just had to go back to the plans and research it a bit more.
On page 10-03 in step 1 it tells you do a lot of stuff to the F-1211G Tail Skid Bracket. In figure 1 it shows that you're supposed to widen the hole to 5/16 and tap the result to a 3/8-16 thread. The problem that I had with this was that it said "1 Inch Deep".
The usual tie down eyebolts you can purchase for this size have a threading that is 1.25" long. Even Van's has them with this length in their catalog. So I started to wonder why the hole would then not be deep enough to fully seat the bolt down to its shoulder. In the evening I posted a question about this on the Van's Airforce Forum and sure enough one builder came back and reported that he had to drill the hole deeper and re-tap it to get the tiedown ring installed. That's exactly what I had been afraid of doing as it would be much harder to do that when the bracket is installed on an airplane.
So I went back to the shop and handled the task of carefully deepen the hole by drilling past the already tapped thread (without marring it) and then tapping the hole so a 1.25" long screw I had lying around would completely seat in the bracket.
So, if you get to this point, make your life easier and drill the hole deep enough right at the first time so you don't have to worry about damaging the threading.
I wrote Ken at Van's an email to see what he thinks about this, if it's a mistake or if there's something else about the eyebolt installation that I just don't know yet.

Anyway, a deeper hole won't hurt but a shallow one certainly could.

Aft Bulkhead Primed

Yesterday it was all shiny aluminum, today it's matte green. That's pretty much the summary of today's day at the factory.
Only one thing is worth mentioning and that's not even related to the priming. I wanted to verify that the thread I tapped for the skid bracket was ok for receiving the tie down hook. I couldn't get a suitable eyebolt at Home Depot but I brought home a 3/8-16 screw which was 1-1/4" long - just as the eyebolt you can order at Avery Tools. Now, when I was drilling the hole I saw the note saying tap 3/8-16 1" deep and I thought to myself, well we better drill this a bit deeper to be on the safe side. So I thought I drilled about 1.5" deep and I tapped as deep as it went without using insane force.
Now the surprise.... The screw did not go in all the way! I measured just a bit more than 1" as requested by the manual. So, now I'm wondering if I should install it like this or make an attempt to deepen it a bit to get to the 1-1/4" for the full threading of the eyebolts? But then why would Van's have requested only 1" of tapping? I assume at this point that there will be washers added to raise the eyebolt a bit although I wonder why... I think I might have to ask the Van's Airforce forum once more for advice ...

Cruising Along

After washing off the roughness of the primed surfaces in the morning and drying the parts, I finally got to the point I like most.

RIVETING!

Even if it's those darn squeeze rivets ;-). So I riveted the flange that will support the vertical stabilizer to one of the formers and I only messed up twice by squeezing a rivet that wasn't properly set in the hole. Why this happened I couldn't figure out but it was an easy job to drill those out and try again.




Riveting the rest of the formers with pull rivets was a blast but it was then that I noticed that I had overlooked something in the previous steps when I was looking ahead and worked on the tail skid bracket.



I was wondering when I was supposed to tap the hole for the eventual installation of the tie down ring and reading ahead I couldn't seem to find it.
Well, that was because it was in the description of the notes I thought I had already processed. Just one short line in the figure was dedicated to tell me I was supposed to drill and tap the hole. No harm done by this oversight as the part wasn't mounted yet and so I had to figure out how to drill a 1" deep straight hole. I knew I wanted to use the drill press for this but the challenge was to find a reliable way of supporting the odd shaped bracket during this process. Unfortunately all my usual tools for a job like this didn't work out. Mainly because I had already done a lot of metal removal work on the bracket and so I couldn't find a way how to hold it in the vise. Well, we are builders and so we know how to improvise... This is what I came up with and believe it or not, it worked great!



The photo of the bracket that was supposed to show the nice threading turned out to be completely blurry, so you just have to believe me that it worked fine :-).

All that was left to do for the day was to remove more blue vinyl of the parts that I decided to prep and prime the following day.

Priming Under Way ...

It was a very long day at the factory and the humidity didn't make it any easier either. But what am I complaining - I got a lot done.
With Dave Gamble's help I figured out how to de-flute a bulkhead stiffener that gave me some headache. This was not an important step but a necessary one to continue the preparation of the next parts to get them ready for priming.
Priming was the main goal today and I got all the parts on the list prepped and primed, despite the heat and the time that just seamed to run away today.
Dealing with the skins was a bit odd as their sheer size and wobbliness makes it tricky to work with them. Particularly if you intend to move them around quite a bit - as I had to to get them from the prepping table to the wash off point (who wants this caustic stuff seeping into the concrete on the patio?), to the drying rack and then to the painting corner.
Speaking of painting corner. The picture with the primed skin sitting on a bucket and my improvised spraying table in front of idyllic desert plants IS in fact my little painting corner. At least it wouldn't matter if you had some overspray in this area ...
So, I finished the formers, a lot of small parts, J-stiffeners and the two basic skins that start the tailcone "covering" process. I guess I will have to wash them off tomorrow and see how far I get with the first assembly steps as I have also a lot of honey-do's to do.

Preparing Parts, looking ahead

I was looking ahead today to scrounge up more parts for the upcoming priming session. The amount of time spent on cleaning the paint gun is a constant and the more parts I can cover in green during one session the less I am complaining about the cleaning time that follows a paint spree. So, I was browsing through the manual to see what else I could find to cut apart and deburr that didn't need any match drilling yet.
I couldn't find much more than two of the J-stiffeners that just needed two holes match drilled that could easily be managed and so I did that. As there wasn't anything else to find for the priming process but it was too late in the day to get into the priming I looked for a little side project that wouldn't carry me away.
One thing to do I found was the AEX part that will take the tie down eyebolt for securing the tail of the RV-12. It needed a lot of trimming and drilling and polishing but when that was done the part then has to be matched with the tail bulkhead and is an important step to finish this upcoming assembly step. It turned out that the little metal saw I brought back from Germany was a real life saver in this step. It cut a very clean and straight line through the AEX to remove the excess material for clearance with the Stabilator without marring up the metal too bad. The Cut & Polish and the Scotchbrite wheels did the rest.

Prepping Surfaces

This is like a deja-vu in slow motion these days. After getting most of the deburring for this section done I moved on to prep the surfaces of the parts that won't any further processing to get riveted. The sheer number of parts to process in deburring and prepping is a bit overwhelming right now.
I finished prepping the formers and other small parts today and I am getting a bit concerned about how to process the skins. I used the lid of the crate the parts came in as temporary work table to lay the skins down and scruff them with Cortec's VpCI-440 but there are 9 skins and I am definitely not looking forward to this exhaustive type of work.
Right now we have about a 100 degrees and 70% humidity because of the monsoons and although the primer would handle these conditions, I certainly don't. Holding off the priming would also delay the build process and there's not a lot of other work that I could do right now as these parts have to be assembled in order to continue the build. I guess I will have to bite it and just see how far I can get in this weather...

Will this deburring ever end?

What a busy day it was... After finishing the prep work on the skins yesterday, I was working my way further through page 10-02 and worked on the fuselage formers. They needed some match drilling on the aft one to support the fixture the vertical stabilizer will get attached to. So, I did that and along with more deburring and polishing. I also looked ahead and searched for additional small parts that would need to get separated and deburred to get a nice little bunch of parts for the upcoming surface prep/priming action that is soon going to happen.
So far I have spent about 14 hours on page 10-02 alone - well, I did work on some items on page 10-03 and 10-04 but they were not really time consuming. Anyway, if this continues to be such a slow progress, then I might not have to worry about how to fill the anticipated huge time gap between finishing the tailcone and waiting for the wing kit to arrive as there might not be any gap ... :-)
You can see the pile of prepared skins and you might notice that I took the time to just partially remove the vinyl on the outside of the skins. I'm not sure if this effort will get rewarded as most of the skins overlap partially and I might just go ahead and prime both sides before assembly anyway. We'll see...

More Deburring and a Maiden Flight

The last two days I've spent deburring the skins and breaking the edges for a nice lap joint when they get riveted together. On Saturday I took the morning off and helped my friend Tom to get the maiden flight of his newly finished RV-6A documented. That was well worth getting up at 4:30 AM and spending the morning at Ryan Field. It was a wonderful experience to see the plane getting airborne for the first time and I couldn't help myself but to think of my RV-12 doing this on some day in the next years.
Today I broke the edges and so far I have spent about 8 hours on this tedious prep job. The next steps will be more exciting and will probably be worth taking photos again.

Back to Building

Finally, I got back to building today. Feels good! I started deburring the edges and holes of the skins. 5 done, 4 small ones to go. Getting the blue vinyl off was pretty easy this time. No photos as there's really not a lot to see. Spent about 3 hours today and probably another 3 hours to tomorrow to get the skins ready for prepping and priming.

Storing the Stabilator

Storing the larger parts like the Stabilator is becoming an issue. Although I found a good solution for the Stabilator by placing it on some swings that are hanging from the covered patio, which proved to be reliable even in gusty weather, I was getting worried that the ever creative Southern Arizona insects or even birds could find the seemingly safe housing the inside of this structure would provide too inviting to resist moving in. So, in order to prevent these undocumented aliens to invade my Stabilator I decided to seal off the possible entry points.
I used a newspaper for the center section to allow a little bit of moisture transfer and I also added 5 packs of silica gel packs inside each side of the Stabilator to avoid condensation.
I hope this turns out to be a comprehensive solution to long term storage until I finish the fuselage and eventually need to mount this part on the rest of the airplane...

preparing tailcone work

Just a quick update so you know I am still working on it... I was taking some time off to enjoy flying the S-12S before Monsoon season kicks in completely and to "waste" some time I wouldn't have to spend waiting for the wing kit otherwise.
But I did at least a little bit of work. That's sorting out the skins, thinking about how to build a temporary work table to do the surface prepping and priming as my little painter's corner next to the garage wouldn't do for the large skins without nicking them in some way or another.
Now it's way into July and I guess this weekend I will start coming back to my routine of working on the plane again. Deburring, breaking the edges and prepping and priming the skins are the most likely candidates on the ToDo list this weekend.

Mission Accomplished

I've accomplished the task of finishing the Stabilator over the weekend. Yay! 4th of July can begin now...
The final riveting of the splice plate and the aft skins went easy and without any incident. You might see that I broke the edge of the skins where they were supposed to get riveted. I was afraid that the force of the rivet would pull the skin up a bit, creating a sharp edge and a nasty look. The tool I have for that from Avery is not that easy to use. You have to take extra care to guide it cleanly along the edge as it tends to run into the skin which creates pretty ugly bends that are hard to fix. This will cause a few problems when I use this one on the tail cone skins, I can already see that.
The other quirk with it is that it is very hard to fine adjust as a little turn on the screw has a very large effect. Oh well, I'll just have to live with it I guess. But if you read this and haven't bought one yet, you might want to try the one from Cleveland Tools as it can't be worse than this one here.
The last steps were the assembly of the control horn and mounting the weights on the Counterbalance Arm. That went well, too although I nicked the powder coating in my vise a bit and so I gave it a little rattle can primer on these spots to keep the steel from rusting.
That was it! Final assembly is supposed to happen later and now I'm heading towards the tail cone.
55 hours went into the Stabilator. This sums up to 116.5 total so far.

Hinges Riveted and Some Prep Work Done

I thought there wasn't much to do until the Stabilator was done but I underestimated the time factor for the few steps ahead of me. It was amazing how much time it took to get them done. And so was the amount of rivets going into the rear flanges. It looks more like the skins are attaching the rivets than vice versa, if you know what I mean.
Anyway, the job was practically easy although lengthy, as I said before. Because of my resolution to prime the inside and all mating parts, I couldn't just rivet away and the blue tape on the pictures indicate some clecos that were not be removed as the splice plate had yet to be primed. So had the aft skins that also had to be partly match drilled with the ribs that were supposed to hold them.
When I clecoed these aft skins to the ribs to do the drilling I noticed that I had overlooked that the skins will be attached to the main skins of the Stabilator and thus will have a mating surfaces that I hadn't primed yet. Oh well, I was at prepping anyway and so I took care of that and sprayed a basically assembled part for the first time (can you see that I am still thinking about painting the plane before final assembly here?).
Priming concluded the day in the shop so it could dry and settle over the night.

Skins Are On

I've finished riveting the skins on. Everything worked fine but I've noticed about three places where the clecos have bent the skin when the weight of the Stabilator was pushing sideways on them. It doesn't look too bad and maybe I can fill this later when I'm preparing the surfaces for painting. I will have to be a bit more careful next time to avoid this in the future.
The good news is, that I also got my A/C unit installed and it works great! It cooled down the workshop from 102 to 82 within two hours and if you stand in the blast of the cool air while it is doing this, you can work along just fine. I am very happy I spent the money on this unit.
This weekend I won't be having a lot of shop time but I do hope to finish the Stabilator at least as there is not really a lot left to do. And then it will be on for the tail cone ...