Lucy

Lucy
Vans RV-7a #73391, N511RV

Her name is Lucy and that's her serial number and "N" number.
Sweetie is so supportive. We are going to travel and see this wonderful country. For those who don't know about Vans Aircraft, check out the Vans Aircraft link. It will take you to the manufacturer's web page where you can read all about the airplane.
Let's get started. Feel free to browse around and return often to keep up with the progress. If you have a comment or question, please use the form at the bottom of the page.
On to the Blog. The cover page is just daily ramblings. If you want to read the assembly details, click on one of the page links. Enjoy.

Friday, February 9, 2018

Aft Top Skins

Yea. Things are really moving. We riveted the Aft Top Skins. Check out the Finishing Page.

Saturday, February 3, 2018

Tips and Tricks

Recently I've noticed photos disappearing from threads. It's because most builders, me included, use a photo hosting site to post. The web sites purge old photos. I've been collecting tips and tricks to finish my build and saved them as pdf files so the photos would survive. I also saved quite a bit of stuff into a word document. Sever followers have asked to see the files so I saved them to my Google drive and posted links. Look for the links below. There's a few caveats.
  • I saved this stuff rather quickly so if it doesn't have the content you want, sorry.
  • The Word document is a living document and I won't be updating it. 
  • The documents are to help me from the Finishing kit forward so you won't find any tips or tricks for earlier in the build. Those have been incorporated into my blog already so look through the pages for what you need.
  • I will be deleting them as they are used.
If they help, great. Build on!

Sunday, January 28, 2018

Paint prep


I keep reading so much misinformation where it comes to preparation of aluminum prior to spraying primer and paint. I've deleted so many replies to threads and Facebook posting because there's so many "expert" opinions out there and I don't want to ruffle feathers. There very delicate!

So what better place to share MY opinion than on MY blog. OK, here goes.

First, two terms are very important. Hydrophobic and Hydrophillic.

Hydrophobic is tending to repel water or fail to mix with water. Wikipedia

Hydrophilic is defined as having a tendency to mix with, dissolve in, or be wetted by water. Wikipedia

Aluminum naturally forms a very thin (~2 microns) layer of Aluminum Oxide (AO) almost immediately upon exposure to oxygen so any aluminum you have in the shop, already has AO. Let's try an experiment. Wet a piece of bare aluminum. Water will bead on the surface. Hydrophobic! Paint doesn't stick either.

What's the problem with AO? Glad you asked. Have you ever tried to paint a rusty piece of steel? Rust is Iron Oxide. Sound familiar? That's because both are an oxidized layer of surface molecules. The problem is AO is Hydrophobic. Remember that term?

That means it naturally resists adhesion. We need a Hydrophillic surface for maximum paint adhesion. Bottom line is you can wipe that surface with whatever high dollar cleaner or solvent you want, but if the AO ain't removed, then the primer no sticky! Yes, it probably will be fine and if you like those high dollar products, go ahead and use them. I'm trying to simplify, save time and save you some cash for that engine and avionics.

The solution is to remove the AO. Thankfully it's very thin and easy to remove. We also need some mechanical adhesion. Basically paint sticks best if the surface has some roughness. It gives the molecules some bite. Another property we will discuss later is chemical adhesion. So how do we get "bite" and remove AO?

Preparation is key and since AO forms quick, we need to be just as quick. Let's assume the part has been fit, final drilled and ready for dimpling. Before we start, go to the local grocery or big box store and look for Bon Ami cleanser. It's similar to Comet and Ajax but minus the sodium hypochlorite (bleach). It's cheap and won't hurt you or Mama Earth.  Ajax and Comet work too but bleach and aluminum don't like to play together and I see no reason to make things difficult. Bon Ami is just fine. Also buy some gray scotchbrite. I prefer to scuff surfaces before the dimpling process because it's very difficult to scuff a dimple. Start by scuffing with maroon scotchbrite. Flat surfaces can be done really fast with a random orbital sander. The scotchbrite sticks to the velcro pad. No need to grind off the metal. Just knock off the shine. Proceed with dimpling.

Before primer, and I mean right before primer, start the prep work. No need for expensive chemicals or solvents. I'll discuss a few later. Let's protect ourselves and Mother Earth. Wash that part using the gray scotchbrite and the Bon Ami. Wash well. The soap will turn dark gray. Rinse it really well. Notice how the water forms a sheet on the surface? Hydrophillic! Ureka. That part is ready to accept primer. Dry it with Nitrile gloves on so you don't contaminate the surface. No need to wipe with solvents. We don't wear belts and suspenders. Use clean paper towels and don't reuse them. Place them in a box for later use but now is not the time or place. If you must wipe the surface, use a clean tack cloth. It is used before paint to remove any lint or debris. Now we need to hurry. Most likely your markings are all gone so quickly remark them. Hopefully you already set up the paint tools and stirred the primer. Remember, AO is forming already.

Shoot that primer, quick! If the part is due for a coat of paint, check with both manufacturers on your paint window. Remember we mentioned chemical adhesion? Well we want to shoot the paint within the best window for maximum chemical adhesion. Usually it's 30 minutes to an hour. We want the two paints to chemically bond before the primer sets. If we wait till primer is hard, then we loose the opportunity to basically glue the two together. That's chemical adhesion. If everything is done right, the primer is mechanically stuck to the aluminum and the paint chemically stuck to the primer. Try some samples to test. Of course the two paints have to be compatible. Don't try and spray a solvent based paint over a water based primer or vice versa.

My favorite test is the Gorilla test. Gorillas are strong right? After the paints have hardened according to the manufacturer, cut a section of Gorilla Black tape. Rub it on the test piece. Leave it overnight or in the sun. Next day, rip it off in one fast motion. If it takes primer or paint with it, something failed. Figure it out and try again. No, my primer and paint hasn't ripped off yet!

I mentioned high dollar chemicals and solvents. I ran some primer and Alodine tests with Alumiprep. I would rate it equal to Bon Ani however, it's an acid and proper handling and disposal of the rinse really shift the scale toward Bon Ani. If you must use a solvent, wear protection at all times and choose one with a higher flash point. High flash point means it evaporates quickly. The danger is that also means it is easily absorbed by your body so take appropriate precautions. Denatured alcohol or lacquer thinner work well for cleaning but neither will remove AO so their only use in my shop is cleaning. MEK has a very high flash point. Stay away. Only use for me was building tanks.

Remember those wet paper towels we tossed into a box. Guess where they get used? Yep, paint clean up.

Lesson over. Remember to wear an appropriate organic paint respirator at all times.

Sunday, January 21, 2018

Borescope

I recently purchased an endoscope (borescope).  Pretty simple and it plugs into my cell phone. Application allows photos or video. Endoscope has an adjust knob for the intensity of the light. Photo attached is the Wing SB area where the Aileron hinge bracket is riveted. Just a quick shot.
USB Endoscope, Depstech 2 in 1 Semi-rigid Borescope Inspection Camera 2.0MP CMOS HD Waterproof
Snake Camera with 6 Adjustable Led for Android, Windows & Macbook OS Computer- 16.4 ft(5M)

Monday, December 4, 2017

HS drilled

Yea. Major milestone and one of the biggest stress points in the build. Drilling those dreaded holes through the Horizontal Stabilizer HS714 into the Longeron. Thanks to Dave Paule for coming up to help with measuring. It took a long time and I walked away numerous times, but she's got an HS!
Details are on the Finishing Kit page.

Friday, November 3, 2017

Back in the factory

It's been a while but I'm back in the factory. Had to make some doughnuts. I drive a RMNP shuttle all summer. It helps pay the bills and buy stuff for Lucy.

For anyone starting and especially those building a 7, I posted a link to my Basic Builder Log (see Kitplane links). It's a nice way to track time and financials, plus there's a pretty accurate 7(a) inventory tab.

Alodine is finally done! All exterior surfaces have been alodined. I plan to vinyl wrap so the conversion coating will protect against corrosion and it adds zero weight so I still get the full benefit from the vinyl weight savings. I've got some samples that have been sitting outside in the heat, sun, snow and rain. Plan is to leave them out there till I pull the trigger on the vinyl. So far all are holding up nicely. One each on bare aluminum, alodine and P60G2 primer.
I learned a lot through the process.
  • The most time consuming part was taping off areas so the chemicals wouldn't end up in the wrong place. Alumiprep will peel P60G2 off just like paint remover. The only tape that held up was black electrical tape. Cheapest was 10 rolls from Harbor Fright. Apply the electrical tape to the edge but leave the opposite edge loose. Then I used Gorilla tape by sliding the strip under the electrical tape, sticky side to the sticky side of the electrical tape to extend the barrier. Every other method leaked.
  • Type of rinse water has no effect. I tried every one. Tap water works just as good. Use a tank sprayer to rinse.
  • I got best results by scuffing first. Random orbital with maroon scotchbrite worked best followed by a wipe with denatured alcohol. Scrubbing wet with scotchbrite works too but way too messy.
  • Alumiprep was easier than Bon Ami but it also worked well. I used foam brushes to apply. Use the widest one possible. Apply it fast. Keep the brush moving and keep the surface wet. Don't let it drip. Drips leave a mark.  Leave the brush out of the solution when it's stored. Alumiprep breaks down the foam. Rinse the cleaner very well.
  • Dry after each step with a hair dryer. 
  • Application of Alodine has to be done as quickly as humanly possible. Large foam brush works here too. Apply it as fast as possible and don't allow drips. Keep the brush moving. The surface converts almost immediately so drips will show forever. Keep it wet for several minutes. at 70 degrees I kept it wet for 10 minutes. 
  • Rinse and dry.
I used a shower curtain sluce to capture the runoff into a large storage container (See Kitplane links). Leave the storage container somewhere safe till all the water evaporates then collect the residue and dispose of properly.

Saturday, April 29, 2017

Finder's Fee Award

I recently received a most appreciated compliment. Vans has a Finder's Fee Award program where one builder recommends another.  I am truly humbled. You know who you are and thank you so much for the recognition.

"When I ordered my wings, I wanted to pay it forward in some way for all the help you've given me on the forums, and from the countless times I have read over your blog. I figured the least I could do was fill out the little form for the finders fee for you when I ordered my wings."