Left aileron

Finished riveting the left aileron. The led was cut according to the plans. The plans suggests that the led is over sized and need to be trimmed. My led on the left aileron needs to be enlarged, and this is with no paint on! Still have not decided paint or no paint, so fine trimming of the led counterweight have to wait in any case.

Aileron and flaps

Trimmed and drilled the led counterweights. The led sounds easy to work with, but is actually very laborious and difficult. Destroyed two drill bits and I hope my vixen file is still OK. Deburred, dimpled and primed the ailerons, but the primer was still a bit moist here and there, so I let it cure overnight.

Started with the flaps, the last moving surface. Cut to correct shape and measured up the position for the ribs.

Right aileron hinge

The holes for the aileron hinge also stiffens up and shapes the aileron. I almost did a huge mistake here because the ribs, only at the root and tip, pushes the two bent halves a few mm apart. When the aileron is laid upside down and I tried to push with a flat hand at mid span, the surface will come too far down. When released the aileron will have a nice banana shape. What I did was to push the edge down with a file to get the lower surface flat on the table, then hold the hinge in place with my thumb and the other finger at the trailing edge without pushing the surface down. It ended up 100% straight.

Had to try the Topgloss once more as well. This time I rolled on a thicker layer, then use a foam brush to smooth it out. It became better, but far from OK on an airplane. High gloss and brush and roller is not a good combination no matter what the advertising says. Also sprayed some transparent coat on a piece of aluminium that was sanded with 1000 paper. Looks a bit cool, but I'm not convinced.

Aileron

Drilled holes for the ribs in the ailerons. A bit fiddling to make it all fit with all the cutouts.

The whole paint stuff is strange. When I oiled my floor in the new shop I used something called "concrete oil" for indoor use. The name is very misleading because it is no oil at all. It is an acrylic emulsion (latex paint) that soaks the surface and penetrates down into the concrete. When cured it binds the concrete together as well as making a smooth surface and is of course water proof. It is also used as a primer for epoxy floor paints. I am very satisfied with the result, it does exactly what it advertise.

This "latex paint" on airplanes is also an interesting thing, but confusing. I have looked at typical Norwegian house paints and there is no such thing as latex paint. What they call latex paint in the US can be vinyl paint, PVA (Poly Vinyl Acetate) or an acrylic emulsion, all water based. It can also be a mix. In Norway I have only seen PVA and acrylic emulsions. The difference is that the acrylic emulsions are superior to PVA. PVA is typically used on ceilings, and as cheap wall paint. Most acrylic emulsions are indoor paint. There are some acrylic emulsions for outdoor use, but most are alkyd paints, some are also acrylic hybrid water thinned alkyd paints. For vinyl paint I have only seen this primer I am using, but that is alkyd based, not an emulsion, not a "latex paint" in any shape or form.

This Stewart Systems looks interesting. My neighbor meant I could simply put a transparent cote directly on the aluminium sanded with 1000 or something sand paper. That could look very cool, but will it stick?

Aileron

Sanded down the test sheets. I will try to polish them in 14 days and see how that goes, not very optimistic though. Graham Smith at Sprite Aviation could tell me that they use rollers, but only on matt and  satin finish, never on high gloss. Makes sense to me. He also said they mix their own paint because the viscosity is very important and it varies with the actual pigment (color).

Cut the aileron led counter weights with my hand saw. That was several hours of hard labor. I wish I had a band saw.

Ailerons, primer and top coat

Bought Topgloss BR (Polysiloxane) at COOP along with some rollers and other stash. Then I went to the drug store and got some 60 ml syringes so I can accurately mix smaller amounts of the Topgloss. The syringes were surprisingly inexpensive, 3.5 NOK or about 0.4 Euro a piece.

Finished deburring the cutouts in the ailerons and measured up all the rivets for the ribs. Then I scuffed a test sheet of aluminium to test the Topgloss. I primed half of it with the vinyl primer and left the other half, just to find out how the Topgloss is with primer and without primer. I let it dry until tomorrow. The sheet is actually a faulty piece of RV horizontal stab skin. I really miss my old priming booth when testing all these primers and coating.

I haven't heard anything from Jotun about using Topgloss BR with no primer, so I just have to try it and see how it goes. If this works out, I will coat the whole plane with Topgloss instead of polishing. I'm not too keen on coating the whole plane with this vinyl primer with rattle cans though. If a primer is needed, then my old Monopol wash/etch primer gives a really smooth and thin coat, if it is compatible with Topgloss. But it is also possible to thin out the canned version of the vinyl primer and spray it on with air and achieve the same thickness as the wash primer (30-40 micrometers). Theoretically a 35 micrometer primer covered with a 35 micrometer Topgloss BR gives a total added weight of approximately 2 kg. This weight penalty is nothing when knowing that the polysiloxane is better than any polyurethane out there. In the cockpit I can also use Topgloss BR, hopefully with no primer.

Then the whole plane will be "Pegasus Grey" with tips and cowling in "Draco Red" and maybe with some trimmings in Draco Red as well.

Cut the openings in the ailerons and Polysiloxane

Cut the openings in the ailerons, only deburring left. Also bought a new orange from Hagmans. It was a bit more difficult to get a good finish, but the amount of pigment was abysmal also here. 4 coats of orange, and I still can easily see through it, it's ridiculous. Obviously I am doing something wrong here.

Looking a bit closer at Duplicolor web site what I have to do is first a plastic primer (also for fiber glass), then a white general purpose primer (white primer for bright colors), then the color itself (2-3 coats) and then a 2k transparent epoxy coat (2-3 layers) to achieve mechanical and chemical strength. This is not exactly straight forward and easy anymore, and with all those coats, it gets heavy. I begin to understand why people like Latex paint or real aviation products. The problem for me is that aviation paint products are practically speaking impossible to get. They can be sent from UK or USA, but the cost becomes ridiculous because they are labelled hazardous goods.

Anyway, I had a real eye opener this evening: Polysiloxane coatings. Going for the Jotun Yachting line of products, I only need one coat of Vinyl Yacht Primer (spray or brush) which I already have, and one coat of Topgloss BR, and it will last forever. Topgloss BR is a new 2k polysiloxane coat especially made for brush and roller. It is supposed to be completely smooth and shiny, even when applied with brush and roller, which in fact is the preferable method. Polysiloxane is superior to urethane in all aspects as well as being non toxic, no isocyanates. Polysiloxane coats are completely resistant to UV and oxidation. Generally a coat of polysiloxane is more corrosion resistant, more weather resistant, higher chemical resistance, more temperature resistant, and more glossy than the usual 2 step epoxy primer and urethane top coat.

The "old" Jotun Yachting method was epoxy primer and urethane top coat. The new preferred method is 1k Vinyl primer and a top coat of 2k polysiloxane. The Vinyl primer is preferred because it is smoother (but also needed for wood). So I wonder, on an airplane it should generally be enough with only a coat of polysiloxane with no primer or anything. In fact what the vinyl primer does is only to make a smooth surface for the polysiloxane top coat when using brush and roller, but it could also be that Jotuns formulation of polysiloxane requires a primer for adhesion? I don't know, but my guess is that using polysiloxane directly on aluminium would require 2 or 3 coats because it spreads so thin. And then it is faster and better to use the fast drying vinyl primer that is smooth and can be smoothed further by sanding. The spreading is incredible. 1 liter last for 30 square meters, film thickness of 30 micrometer. The older urethane top finish have the same film thicness, but only goes for 16 square meters due to higher VOC content.

I have read several places that people are using some new paint system and using only brush and rollers, Sprite Aviation for instances. This can only be polysiloxane coatings I guess.

So I ended up "Acetoning" all the orange paint off the tips. From now on there will be only polysiloxane coats on the Onex, with some Vinyl primer here and there (if needed). But this also means that I have to wait until I have more surfaces to cover because the paint is 2k. Another thing is that Jotun don't have orange, they only have a whole bunch of modern non-colors and "Draco Red". So Draco Red it is. Under the inner wing section and on the underside further back I will have some gray polysiloxane to protect the aluminium during the winter.

Measured ailerons

Cut the ailerons to correct length and measured up all the internal cutouts and ribs. Also deburred all the ribs and plates.

Changed the color from dark green to bright orange. Dark green is nice, but it's so dark that it only looks good in sun shine. Here in Stjørdal the sun is not something that is shining all too often, and then the airplane will look too dull and dark. With orange tips and cowling, the airplane will look similar in color to the picture of the Trial further down (or ordinary Sonex polished style with orange instead of yellow). I think that will look cool, also on rainy days.

The Duplicolor turned out to be really a turn down. The finish really is nice and shining, but there is too little pigment in there. It is literally impossible to cover anything if the prepped surface is anything but white, and when the Duplicolor plastic primer is transparent, there is a problem . The tip that was partially green is impossible to get orange, and the seems in the glass fiber (dark color) shines through. I am also skeptical about duplicolor aluminium primer. I tried to sand it, and it goes off in a couple of wipes. The Jotun Yacht vinyl primer on the other hand, is 10 times as durable and can be sanded to a smooth finish. I also tried the houshold "Quick spray" primer from Scanox, it is much more durable than the Duplicolor. At least the Duralac works really well, and that is the most important thing. The Jotun Vinyl primer can be put on anything, and it can be covered with 2k paint.

I put the dimple die in the drill and sanded it to #31 size, it took ages. On the rudder about 1/3 of the stems had to be sanded a bit. From now on all countersunk skins will be #31.