Horizontal and Elevator Fairings

[Doggitz]

I have built up the fairings on my horizontal and elevator. I started with balsa blocks and then added 4-5 layers of superfil and sanding until I was happy with the shape. The problem is that with all of the sanding, I managed to sand through some of the powder coating and am now left with bare metal. I tried using a bit more superfil to cover the metal, but it changes the shape somewhat. My question is what to use on the exposed metal. Friends have recommended everything from varnish to zinc chromate to auto body primer. The area exposed is at the very outer curve of the HS and elevator. width is about 1/8 inch and length is about 3-4 inches. I have thought about the polyfiber primer that I plan to use on the wing spars, but there is no info on brushing this stuff on. Using a spray gun seems like huge over kill, but I could completely cover the polyfil fairing and make it white, like the powder coat.

Any thoughts, suggestions would be appreciated.

Fred

Here is a picture from before I finished the sanding and shaping (it looks way better than this now)25113

[efwd]

Some people never had powder coat. It's simply primer. Then Paint. I used metal prep and a tack cloth to whipe it down immediately before I rattle canned some primer onto it.

[jrevens]

That's not a big deal, Fred. Just use something like automotive primer or touch-up paint to protect it from rusting now. When you get around to covering you can lightly sand & use the recommended paint for your covering system to coat that area. It's a lot more hassle, but I used the paint that I used for my fiberglass parts to repair any dings I found in the powder coat. It is an acrylic urethane made by PPG. When cured it rivals the hardness of the powder coat and perfectly matched the white color of mine. I'd mix up a small quantity in a dixie cup using measuring spoons to add the proper amounts of paint, reducer and hardener, then I'd apply it with small disposable paint brushes. I did some welding on my fuselage to add a second ground-handling handle & an antenna mount between the turtle deck & the vertical stabilizer (mine was built by the factory before they started adding that antenna mounting plate), and spray painted those areas. Just for the conversation, I added that plate a little farther aft than the factory does it, for more clearance from the turtledeck, and started my optional tube to alter the sweep up to the vertical fin there. Because of that I have a little bit different shape back there than most everyone else.

[jiott]

You will need to coat the balsa wood with the epoxy varnish, the same stuff you painted the wing and tail wood ribs with. Its great stuff and will be fine to protect the bare metal spots on the horizontal and elevator tips. It can be brushed on, at least two coats, 3 is better.

[jrevens]

Some people never had powder coat. It's simply primer. Then Paint. I used metal prep and a tack cloth to whipe it down immediately before I rattle canned some primer onto it.

I think that it is safe to say that powder coating is a hard, durable finish coat. It's definitely not just primer. There are some specialized primers that can, and some say should be used underneath it.

[jiott]

Personally I trusted the epoxy varnish for spots like that, but if you prefer you could use the epoxy primer that comes with the kit (maybe it is optional). If I'm not mistaken, I believe the build manual recommends that epoxy primer to touch up bare spots in the powder coat.

[jrevens]

Some people never had powder coat. It's simply primer. Then Paint. I used metal prep and a tack cloth to whipe it down immediately before I rattle canned some primer onto it.

I wrote -
“I think that it is safe to say that powder coating is a hard, durable finish coat. It's definitely not just primer. There are some specialized primers that can, and some say should be used underneath it.”

Sorry, Eddie!... I understand what you were saying now. It’s clear you were just differentiating between powder coated & non powder coated. I’ll learn how to read someday, maybe!

[Doggitz]

Thanks to everyone who responded. I don't recall seeing anything in the manual about touch up, but perhaps it is buried in the checklist before covering.

Fred

[Eric Page]

See section 2, page 3: Powdercoated Parts Preparation.

[Doggitz]

Eric:

Thanks - I will have a look


Fred

[Doggitz]

Thanks for all the help on my previous post. I have a new question.

I am fitting the horizontal to the fuselage to check it prior to bolting into place. I bought the "STI" aerodynamic strut option for the horizontal stab. I proceeded per the manual to attach the struts to the horizontal using the rod end fittings, spacer, etc. I found it easier to fit the rod end fitting to the horizontal first and the "tab" end to the fuselage after that. The tab ends of the struts bind against the mounting flanges on the fuselage and look like I need to grind off some of the strut mounting tab - maybe 1/8 inch max. Has anyone else had this problem and needed to tweak the tabs ends? Please see attached picture - the blue portion is just tape that I put on the struts to protect the powder coating.

My second question is the position of the rod end fitting on the other end of the strut. Both sides have the rod end screwed in almost as far as they will go. Is this normal? I realize that I will have to do an adjustment on them later to be sure that the horizontal is sitting properly.

Thanks fort the help

Fred

25215

[mattkalin]

[QUOTE=Doggitz;93287]Thanks for all the help on my previous post. I have a new question.

I am fitting the horizontal to the fuselage to check it prior to bolting into place. I bought the "STI" aerodynamic strut option for the horizontal stab. I proceeded per the manual to attach the struts to the horizontal using the rod end fittings, spacer, etc. I found it easier to fit the rod end fitting to the horizontal first and the "tab" end to the fuselage after that. The tab ends of the struts bind against the mounting flanges on the fuselage and look like I need to grind off some of the strut mounting tab - maybe 1/8 inch max.UOTE]


https://www.youtube.com/watch?v=eTTEiXAZk2A Watch this video around 11 minute mark regarding adjusting the horizontal struts.

[Doggitz]

MattKALIN

Thanks for the video link. That is the exact problem that I am having. I will follow your lead and take it down a bit


-Fred