Horizontal Stabilizer Completed!   April 29th, 2006

I got my pneumatic squeezer back from The Yard today. It’s even better than before!
I would definitely recommend their rebuilt squeezers as an alternative to dropping half a grand on a new one.

Anyway, with the squeezer back, I quickly squeezed all the rivets around the periphery of the stabilizer. Finally I peeled off the blue plastic. What a beautiful sight!

Soon thereafter, I realized I needed to store this sucker somewhere out of the way. Fabiola suggested the best thing to do would be to hang it on the wall of the garage. I used two bike hooks and some cargo tie downs. I also used a piece of foam I had laying around to keep the stabilizer from hitting the wall:

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More Horizontal Stabilizer   April 24th, 2006

Not much happened today. Just clecoed the rear spar so the whole assembly can be handled a bit more easily.

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Yet more riveting..   April 19th, 2006

I riveted some more of the skins today. At this point I’ve put in all the rivets that require a gun and bucking bar. I am now waiting for the guys at The Yard to get my pneumatic squeezer back to me so I can finish off this part.

Tomorrow I’ll spray some primer over the parts I scuffed up with the bucking bar and then I’ll cleco the rear spar in place.

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I finished squeezing the last few rivets in the spar using Bruce’s squeezer, and then got to work on assembling the HS for riveting. I made some simple wood cradles out of plywood and duct tape so I could stand the pieces up on the workbench.

Fabiola helped me shoot the rivets along the center rib, but said she was too sweaty for pictures, so no pictures of the riveters this time.

Now I need to get a small enough bucking bar to fit the front spar channel, so we can do those rivets.

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More Pneumatic Squeezer..   April 15th, 2006

Today I spoke with Jerry at the Yard. Pretty refreshing to call a company for help and talk to someone who actually knows what they’re talking about!!

Anyway, I told Jerry the flapper piece was fine, and the problem is probably in the air intake valve. He told me to go ahead and send it back to him for repair. He also mentioned their turnaround time is usually one or two days (cool!)

Also, Bruce Wagner, fellow RV7A builder and coworker, offered me to let me use his squeezer over the weekend. So, I’m all set to finish putting together the horizontal stabilizer!

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I emailed The Yard last night, and today I got a reply saying it was probably the ‘flapper’. This is a piece of angle that presses on the air intake valve and makes the squeezer squeeze. I looked at it, and sure enough, the ‘flapper’ is just fine. So, I decided to take apart the squeezer and see if I could figure out 1) how the heck this monster works and 2) why does it not work!!

So, after removing the six hex bolts that hold the bottom piece in place, I found that the problem seems to be in the air intake valve. I can press on it with my thumb (with the ‘flapper’ sitting on the table) and if I wiggle it just so, I get a full blast of air. Otherwise I get just a little bit of air.

While troubleshooting my problem, I learned how the squeezer can deliver such large force to the rivet set.

As you can see in the pictures above, there is a big piston inside the squeezer. As air is let inside the chamber, the piston is pushed up. The wedge-looking piece pushes against two bearings inside the squeezer. One of them is fixed (i.e., it rotates only). The other bearing can move ‘away’ from the first one. So, as the wedge is driven between the two bearings, the ‘moving bearing’ will push against another level, which in turn pushes the squeezer shaft out with a lot of force.
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As I said on the previous entry, I figured out it would be a good idea to let the primer dry before messing with the parts again.

So, after a couple of days, I was ready to start setting rivets. I riveted the two reinforcement bars, and about half of the end brackets. At this point I noticed the pneumatic squeezer was delivering very little force, and figured something was up…

Sure enough, my squeezer is broken! It will only squeeze with full force about once out of three times I press the trigger. I figure this thing should be under some kind of warranty, so I’m going to email The Yard and see what they say.
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I finally got to prime the horizontal stabilizer. I used the AFS water-based primer.

I started by washing all of the parts with dishwashing soap (everybody says ‘Dawn’, but we actually use ‘Joy’ in our house!). After drying, I brushed on the AFS Aluminum Etch, which basically removes anything that the dishwashing soap missed. The instructions on the Etching solution talk about the water ‘sheathing off’ after rinsing. I wasn’t exactly sure what this meant until I actually tried it. Sure enough, after rinsing the parts, water will ‘sheath off’! i.e., there will be not a single bead of water on the piece.

After drying again, I laid out the parts on some chicken wire between two sawhorses, and started spraying:

Some things I learned…

  • My Harbor Freight HVLP detail gun seems to work pretty good, with the exception that there is no vent hole in the gravity fed tank. After a couple of seconds of spraying, paint stops coming out until I open and then close the cup again. Next time I use it I’m going to drill a very small hole at the top of the cup.
  • The paint looks like crap right after it is applied. However, 1) This is primer, not paint, so don’t expect it to look as glossy as the white powder-coated pieces that come in the kit. 2) It will look much better after it dries.
  • The primer will harden considerably in about two days. It is VERY easy to scratch it off in the first few hours after application, so great care is required. The best thing to do is to spray the parts and just leave them alone for two days.
  • Two coats is enough. After riveting, I will come back and spray the rivet lines and other places where the bucking bar may have scratched the primer off.
  • After the primer is dry, you have these nice white pieces. As you handle them with your dirty hands, black smudges start to appear. Obviously, these are harmless, but make the pieces look dirty. I used rubbing alcohol to clean up.
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Assembling the VS Skeleton   April 6th, 2006

Today I clecoed together the Vertical Stabilizer skeleton and match drill all the rib-to-spar holes.

Below is a picture of the skeleton.

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Not much to report…I spent about an hour today deburring the Vertical Stabilizer ribs and front spar. I am still waiting for my replacement bracket from Vans.

Hopefully I can assemble the VS skeleton tomorrow and get it all drilled out.

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