Priming the Rear Spar

Another priming day.  I really don’t enjoy priming, its probably the only part of building an airplane that I despise.  It very well could be my process, so I think I will try something different on the ribs.  However, I followed my normal routine for the spar parts:

  1. Scuff all the parts with maroon scotchbrite pads.  My goal was to not take off the alclad, but give the primer a good surface to adhere to.  I figure having alclad AND AKZO primer would give me good protection.
  2. Clean the parts with acetone.  This gets rid of oils, scuffing dust, and other contaminants that would cause the primer to not stick.  I have found I have to clean each part three times with a fresh paper towel before the paper towel comes up clean.
  3. Spray the parts with primer.

Now, this may not seem like a lot of work, but all that scuffing and cleaning is boring and very tiresome (repetitive).  I am seriously considering switching methods to the Alumaprep, Alodine and primer methods as they dont require no where near the scrubbing and scuffing.  I could just dunk the parts in bulk into tubs of the stuff and let it do its magic.

Anyways, I followed my normal procedure for now, and scuffed up all the parts, cleaned them with acetone and then sprayed AKZO.  Here’s the photos of where I had them all scuffed up, cleaned and re-marked ready for priming.

I will admit a mistake:

It’s hard to see but I only mixed up about 3 ounces of AKZO (1.5 of parts A and B). I let it have its 30 minute induction time, while I suited up.  I thought it would be enough but I learned about halfway through my spray session that it was not enough.  I was only able to finish about 90% of the parts, and I needed to go back and touch up some bare spots on the spars.  SO… thats my mistake.  I had to mix up a second batch, this time doing another 2 ounces of mixed primer and let it sit another 30 minutes to induct.  After it was ready, I finished up my priming session, and left the parts in the booth so the offgases would get ventilated outside.  AKZO has a tendency to off-gas as its curing, and its a strong smell, so they can hang out in the booth for a day or two and cure.

Of course, heres the painter selfie for proof that I did the work

Here’s all the photos from tonights work. I’ll add the rest of the photos when the parts cure and I can get them out of the booth and in to good light to snap some photos.

Google Photos link:

Hours Worked: 3.5

Priming the Last Parts of the Empennage!

Well, tonight was priming night, and its the last priming session for the entire empennage! I am kind of glad to be honest, spraying AKZO is an ordeal with all the PPE and prep work that has to be done.  However, it leaves an absolutely awesome primed surface, that is incredibly durable so I guess its worth the trouble.  I only had a few remaining parts from the left elevator that needed priming, and I have decided I am not priming the trim tab.  Its a super small piece, and the assembly work left the trim tab fairly closed, so I wouldn’t get much coverage in it anyways.  Even if the trim tab starts corroding (it won’t its alclad), the entire thing will cost about $50 in parts to replace, and maybe 8 hours of work. The trim tab finished out so well, that I didn’t want to chance ruining it by trying to prime it.

Here’s my obligatory priming selfie!!!

Like all priming sessions, I started out by scuffing up the parts with maroon scotchbrite pads.  These things work great at scuffing the alclad surface, but not removing it.  I essentially am just removing any of the alclad surface corrosion and giving the primer a good surface to “bite” onto.  Once I had all my parts scuffed up, I did a quick wipe with a microfiber cloth to remove the dust that scuffing leaves behind.  I have found this small step makes it WAY easier to clean with acetone.  Once I had the dust off the parts, I cleaned each one with acetone 3 times each and using a clean side of a paper towel every time.  I like to clean the parts until the white paper towel pulls away clean from the part.

Then, I mixed up the AKZO and let it kick-off for the 30 minutes it needs, stirring it occasionally.  I made 4 ounces of AKZO for this small batch and then poured it into the PPS cups for my HVLP sprayer.  While the AKZO was kicking-off, I suited up into my tyvek suit, donned my full face mask and sealed off the spray booth and ventilated it outside.  Like usual, AKZO sprays super easy, and covers wonderfully with an HVLP.  Usually once quick pass is enough to cover the part completely, with only needing a few small touch up’s in the shadowy areas.

Once I had all the parts sprayed on both sides, I cleaned out my sprayer and I’ll leave the parts to cure for a few days.  AKZO dries really fast, and is workable in a few hours, but I like to let it completely cure before working with it.  Its very scratch resistant if you do.  Not many photos tonight, because, well its priming.  Its pretty much the same as the other priming sessions 🙂  Here’s the ones I did take though:

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Google Photos link: https://goo.gl/photos/Bm6Ck64TDSQRLVNj7

Hours Worked: 3.25

Priming a Few Parts For the Right Elevator

I started off tonight by priming a few little odds and ends for the right elevator. I had missed the little doublers in my first round somehow, and I needed to prime the replacement counter balance skin too. I decided to mix up a very small amount of AKZO and use my primer pistol to spray these few parts. The primer pistol is dead simple, and uses film cans as its paint cups which makes it easy cleanup.

This was the first time I have ever used this primer pistol, and its pretty convenient,  However, it sprays super heavy, so I had to back way away from the parts.  I did get a little bit of bubbling on one of the doublers from the heavy spray, but I’m not worried about it since its a part that will not be visible.  I followed my normal procedure of scuffing with scotchbrite, cleaning with acetone and priming.  I am pretty happy with the way these parts came out, regardless of the heavy spray from the primer pistol.  It done a decent enough job, and the next time, I will just keep the tip far away from the parts to get a thinner coat.  I do like how easy the cleanup is: Just toss the little film can and run a small amount of acetone down the tiny copper tube.

That was pretty much it for this small session.  After cleaning up, I took a short break and will come back down to finish up the skeleton in another session tonight. Spent about 45 minutes on this, counting the 30 minutes for the AKZO to catalyze after mixing it up.  I used that time to prep and clean the parts.  Heres all the photos:

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Google Photos Album link:

Hours Worked: .75

Priming the Rudder and Right Elevator

Priming and Stiffeners….the two things I like the least on this build.  But, you can’t have an airplane unless you do these two things.  I have been holding back several bits of work in order to batch all my priming into one big job, and tonight I planned to tackle this.  I won’t be batching parts up any longer….more on that later. All in all, I had all the parts for the rudder (skins, stiffeners, skeleton and doublers) that needed to be primed, in addition to the right elevator skins, stiffeners, and skeleton.  In hindsight, this was way to many parts to deal with in one session, and I don’t think I will batch this many up next time.

I started out by scuffing all the rudder parts with brown Scotchbrite pads first and then using a microfiber rag to clean the dust off.  Then I put them in the paint booth to be cleaned with acetone before being primered.  After the rudder, I gathered up all the right elevator parts and did the same procedure with them, making sure to keep these parts in a separate pile in the paint booth to avoid confusion with the rudder parts.  This is where I should have stopped scuffing and went right into priming, but my wanting to get things done told me “go ahead and get the right elevator skin and stiffeners done while we are at it!!”.  I already have these parts drilled and ready for priming, so I went ahead and added them in to the work.  My hand was KILLING me by the time I was done with all that scuffing, and I still have to clean and prime all those parts!!!  Since I had scuffed away the Alclad and the oxidation layer, I couldn’t leave them overnight, because they would oxidize again, and I would have to scuff again.  I powered through the pain of a cramping hand and kept working. 🙂

  

Now I had all my parts in nice neat stacks in the paint booth, I went ahead and proceeded with the work of cleaning the with acetone to remove oils and residue, cleaning with paper towels until the towel came back clean with no black on them.  With scuffed and cleaned parts I was ready to prime! I learned tonight that I absolutely despise all these little stiffeners, they are so fiddly to scuff and clean!  I need to find a better solution to this nagging problem.

I mixed up a full 20 ounces of AKZO primer in my PPS cup.  I figured I would use most, if not all, of the primer so I filled it up with equal parts A and B, and let the mixture sit for the 30 minutes to activate.  I used this time to put on a full Tyvek suit with booties and hood, and then donned a full face respirator with really good 3M filters designed for spray painting, and organic vapors.  Then, setup my parts on the spray table and closed up the paint booth.

  

After about 45 minutes of spraying parts, I had everything done and looking good.  As usual, the first spray was a little heavy and ran a bit on the rudder trailing edge, but I’m not worried about it since its primer and on the inside of the rudder, no one will see it.  AKZO sprays really easily, and drys quick making it super easy to use.  Now, I’ll let the parts lay up in the booth to cure over the next couple of days.  I’m going to put an order in for some ProSeal and pickup some angle aluminum to get ready for riveting the rudder trailing edge.

Heres all the photos from tonights work:

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And heres the Google Photos album link:  https://goo.gl/photos/6Ac2yeEXDjRy2RPD6

Hours Worked: 5.75

Priming Horizontal and Vertical Stabilizers

Today was priming day! The weekend is about the only time I have available where I can get priming done. I am spraying the parts outside to keep fumes out of the house, so I am at the mercy of good daylight. Yesterday I my Shriners unit had a parade, so I drove my little parade car in it, and didn’t get home in time to work so today was my work day.

I have the entirety of my horizontal and vertical stabilizers to prime today, and I got started around noon. I first scuffed down all my parts using a maroon scotchbrite pad. My goal was to only remove ay aluminum oxide that may have formed, while also giving the AKZO some tooth to bite into. I did not want to remove the alclad, as I have decided to leave it on the aluminum as an additional layer of corrision protection. The AKZO will be my primary barrier, while the Alclad will serve as a secondary. I also realized that the dimples tend to eat up a scotchbrite pad, so I may start leaving my dimpling duties until after I have primed, this might make scuffing easier and less abusive on the pads.

After I had all my parts scuffed up, it was time to clean them off. My chosen method is to use acetone. This will get rid of any chemicals and oils on the parts and give the primer a good clean surface. I first started by wiping the parts down with a dry micro-fiber cloth, the goal here is to remove any of the dust left from the scuffing.

Then I used paper towels and acetone to clean the parts completely, until nothing was being left on the paper towel. The skins were a little tricky because they had the red ink from the aluminum company, so I wiped it off with acetone first to keep it from smearing across the parts This made it a little easier to clean.
Here’s a glimpse of a skin scuffed, cleaned and ready for primer:

Next step was to mix up my AKZO and give it the 30 minute induction time. I took a rough guess and figured a total of 8 ounces should be plenty for these parts. I shook the **** out of each of the AKZO cans, mixed them up with a paint stir, and poured 4 equal parts of “Part A” and “Part B” into my PPS cup. I learned that pouring the clear hardener (part b) first makes it much easier to see the ratio lines on the PPS cups. Here’s my primer chilling out in the cup, inducting:

While the AKZO was inducting, I moved my parts outside and onto my spray table. Unfortunately, I had more parts than I had table so I used some old cardboard boxes for the others. I figured I would start flange up on the boxes, so when I flipped them over the flanges would hold my freshly painted surface off the cardboard and not smear it. It worked out pretty good.


Eventually I had all of my parts sprayed, and looking great. This stuff goes on really easily, and dries fast. I am also happy that you don’t have to hussle to spray whats in your cup because you have a pretty long working time in your cup. Now, I will admit, my skins have some uneven spots where some areas was sprayed heavier than others, but my main concern was to make sure my skins had adequate coverage. I am not trying to get a show-room quality paint job since the only people seeing this will be me and the inspector. As long as there is good coverage, the AKZO will do its job preventing corrosion. I also had a few small runs on some of the parts, but again, I am not going to worry about them unless the run causes some assembly interference.

I had a few small places on some of my parts that I had to spray again to get good coverage, but I had plenty of AKZO in my gun so I didn’t have to mix any up. The 8 ounces (I think the PPS cups are measured in ounces) ending up being just about the right amount, I had good coverage on my skins and parts, and had a little left over to touch up the areas that I missed. After it was all done, I had probably .25 ounce in the bottom of my cup, very very little. I ran some acetone through the gun’s gravity feed and then moved the parts from outside onto my work tables to they can finish drying. They turned out really nicely!

I’ll let these things harden overnight, and probably start assembling them all together tomorrow or Tuesday night. This green color will look nice against the white/grey hinge brackets and gold colored rivets.

And always, here is a complete album of tonights photos: https://goo.gl/photos/X5mgorU1X4jzY4tE9

Hours Worked: 5.25