Priming and test

Primed the rib doublers and mechanism using this 3 in 1. The rest of the ribs will only be primed on the mating surfaces with vinyl.

I also made a test piece from some scrap 6061. The plan was to put in on my boat, but then I remembered my boat is on land this winter for a little fix up this spring. It's only a few meters from the sea, so I will put it there anyway and let it stay for some years. I just have to test how this 6061 and stainless rivets holds up in a real marine Norwegian atmosphere. So I made some holes and riveted a few rivets.

Half of the piece is primed with Jotun Vinyl primer. From left to right: [-, Duralac]  [-, -]  [primer, Duralac]  [primer, -]. The lower rivets are solid AN rivets for comparison.

I also looked at the Jotun polysiloxane test pieces. It has really cured by now and can withstand Aceton, ethanol and xylene just as good as my old epoxy primer. It is impervious to UV and really hard, similar to polyurethane. It really is high gloss as well. If I could just find a way to put it on so it looks remotely acceptable... Have to try to spray it on tomorrow using my primer gun and see how it goes, but I am afraid it is too viscous. 

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.