Stuka Stunt Main Forum · 18 of 18 known posts recovered
Sealing your hinge line with monokote
For a nice close hinge line when using monokote, try making your hinges with the monokote, when done correctly it not only seals the hingeline but has a spring back to neutral effect,
Oh! and there fuel proof too! just like the rest of the plane. and the good part is IF you should EVER need to do a repair they will always match
Best, Hoovie
First, apply a strip of monokote to the trailing edge and the leading edge of the control surface. This will insure that the area won't soak up fuel like they will if you don't do this. I cut the strips wide enough that they wrap arounf the area and about a 1/4" onto the top and bottom surfaces of the trailing edge and control surrface leading edge.
If you install monokote hinges before you apply the covering, they will not tend to curl when wiping the model down. Just trim at the edge. Of course this also hides the hinges, and will make it a bit more of a problem should you ever have to do any changes. The possibility of this though is small, as has been noted, these are pretty durable and will usually outlast the life of the model.
I prefer, and have found, that the hinges I've made with this method, are free and do not act "springy", which I would consider a drawback.
Try threm on a sport plane first, and see if they are for you.
John
I would avoid monokote hinges on any airplane that was going to have to last a while. I've used them before, and they work great for a while. But, inevitably, they become brittle from UV light (just like it does on the roll) and simply crumble. I have a monokote hinge on my Skyray, and I've replaced it 3 times and it's now taped up with Crystal clear tape to hold it together. And it doesn't have a lot of flights on it, probably less than 200.
The "spring-back-to-neutral" effect is something that can be minimized. The very last thing you want or need is anything else trying to center up the controls. That's why you don't see a lot of "easy hinges" - they want to flatten out.
Trim monokote can be used for sealing conventional hinges, but it's very stiff compared to other alternatives like FasCal or mylar tape like Moore or Scotch. And it splits after a while, and trying to remove it is a real mess, because it leaves the colored adhesive behind.
Brett
Another problem is using clear monokote to cover and hinge and then painting the model. If you have the misfortune to have a hinge tear it is a real problem to replace it and blend in the paint. While I use them for sport planes I'd use something a little more permenant on my top of the line ship
However, as much as I appreciate and use plastic films for covering Stunt models of all sorts, I would not consider MonoKote hinges for a full-boogie piece. Brett is right, the stuff can go bad on ya, made worse if the film is work hardened during application. (Yes, it is true; plastic film is relatively easily work hardened. Get that tip covered NOW, use plenty of force and quit screwing around with too much heat...)
Most problems with film hinges trying to self-center come from sucking the surfaces tightly together, only to discover the perfectly straight LE and TE pieces aren't near as perfect as first thought.
The big deal for me is that I do not want surfaces to self-center in the first place. Secondly, they will sometimes self-misalign, this being even worse.
It is my view that even sport models deserve the very best commerically-produced hinges you can find, although film hinges do offer some attractive features. Today I would only use film pieces on a 1/2A RC model, one not intended to live a long life to begin with.
Danny Dirt
I'm curious about the brittle issues with your monokote hinges. More exactly, I'm wondering what part of California you live in. I've had monokote hinges last about three years so far, but less than 200 cycles on the plane, so I suppose less sun exposure. But if you live in Southern California I'm wondering if there really is something to all the fuss about ozone out there. I know ozone attacks synthetic and natural rubbers and plastics, especially in collusion with sunlight. In my experience with monokote, limited as it is, I've never seen it go brittle with the exception of wing tips that had alot of heat and fooling with when it was initially applied. Perhaps environmental conditions in California have something to do with the monokote not holding up (this isn't a crack on where you guys live, I'm just curious) I live in Virginia where it can get plenty hot, but where ozone is comparatively low compared to out west. One of the best local monokote finishers I ever saw, the late Mike Garmon, always used monokote hinges on airplanes that lasted many years and in some cases had hundreds of flights on them. He told me several times he had never had a failure of a monokote hinge. I'm thinking that the combination of less strong sunlight and less ozone may make monokote hinges more viable here than in CA. That is not to say they are superior, but they have their place when doing a monokote finish. Personally, I use monokote only when in a hurry because if we don't have the brittle effect, we (at least I) have the prune effect on a hot day. The dope and paper ships seem to hold up much better to a hot day. But when the average service life of my ships in only about nine months, I'm not sure the dope jobs are worth the effort.
Steve
For the record, I live in the greater San Jose area. The air quality varies, but it's usually pretty decent. For instance, I've never seen it as bad as I did yesterday in Salt Lake City. All the "smog Nazi"s for all their excesses, have had good effect. I would rate the average air quality to be higher in the south bay than is average in the midwest/southeast. Bear in mind, even though we have a lot of concentrated population, the air coming in has only recently evaporated from the pacific and is pristine to begin with. Air on the east coast comes across most of the country first.
But I think any difference is much more likely to be UV light than atmospheric ozone. Outside of the mountains, most of California is near-desert. The light is much more intense than back East. A good indication of this is that I get sunburned in about 45 minutes here. When I lived in Kentucky, I had never been sunburned in my life and sunblock was a non-issue.
But UV is clearly not the entire problem. - even when I lived in the southeast in various places, Monokote was notorious for getting brittle over time, even when just on the roll. Monokote also outgasses over time. Just like a car interior, that "new car smell" (solvent outgassing from the vinyl) goes away and that is a big contributer to the problem as well. An old roll of Monokote is much more difficult to apply than a brand new one, just because the old won't stretch.
You can test for this yourself. Roll a little off the roll, peel off some of the backing, stretch it tight, and thump it with your finger. "Good monokote" goes "thud", and is about the same consistency as the backing. "Bad monokote" is clearly more stiff than the backing. The smell is a lot less on "bad" monokote. Lot's of times, you can roll a couple of bad wraps off the roll, and use the rest.
I wouldn't consider myself the world's foremost expert on the topic (some of the really good R/C Monokote jobs are mind-bogglingly good), but I have used it a lot and recommend it for anyone who can afford to give up about 2-3 appearance points. But my hinge experience has not been particularly good. The tendency to self-center is enough of a reason to use other methods, and the brittle issue is jus the topper.
Brett
John
No, just passing through, with an 18 minute layover. Lots of Olympic types at the airport!
Brett
Having had more time to think about it, I guess a big factor for me is removable flaps and elevators; as in while film hinges can be cut away, replacing them results in a horrible mess on an otherwise nicely-finished model. A second factor is that no matter how tricky one is, the hinge material can still easily be seen by judges. There are ways to make the installation nice and neat; you just can't hide it. But with nylon hinges the ajoining surfaces can be covered with one piece of film, adding to the effect.
Models should not look like prunes, which is why I continue to cover open areas with Micafilm, only use MonoKote over solid surfaces. Micafilm is exceedingly stable, presumably because there is no glue on it. And all MonoKote is applied with original formula BalsaRite thinned 50/50 with acetone, this mix applied anyplace where MonoKote will be later. Try it on scraps of wood, might even revisit a Stunt News article on film covering I wrote several years ago. When I am done, the MonoKote cannot be removed from the wood. No prune effect...
And Micafilm! About two weeks ago Buzz Wilson and I pulled a Micafilm-covered Monoboom (AMA Combat model of yesteryear) from my attic. The model is at least 12 years old, has never been flown, had been in the attic for about 9 years; lots of hot/cold cycles over the years. The Micafilm was still tight, not a single booger, pucker, wrinkle or prune-face stuff going on.
My '98 Smoothie, covered in MonoKote and Micafilm, and a piece just everybody is tired of seeing come out of the van, has not had an iron or heat gun within 20 feet since the time it was new. No wrinkles, none. Ever.
While I should not admit it, following each good cleaning with "Tuff Stuff," all my models get a good shot of Armor-All. Let it soak in a bit, wipe clean.
Not that I've ever had anything wrinkle in the sun.....
Nils
Micafilm available from Tower Hobbies. It's actually a Coverite product, look under their heading.
While I've been telling people about it for years, few seem to actually try Micafilm. No glue, so it's real light. Pretty strong as well, although I have no data. And it sorta looks like a cross between doped silk and doped tissue. I have actually grown exceedingly tired of answering the "What's that covering? Is that silk? Is that tissue?" questions asked at each and every contest.
If you've swallowed your pride, lowered your standards to my level, cover everything in plastic film, Micafilm is an excellent material.
Oh, Micafilm is nothing at all like polyspan.
I had forgotten that actually there is excellent data on the overall strength of Micafilm. The Nostalgia Combat guys here in the NW are flying real old British Combat designs with 2.5cc diesels for power. They are trying to replicate the flying abilities of these old models (very bad idea) and to enjoy the basic toughness of same. Without, you know, the work of silk, nylon, dope, etc. While they, like me, have very low standards and so will cover with plastic film, the toughest models are wrapped in Micafilm.
Micafilm hinges sound to me like a particularly bad idea; but then I don't care for MonoKote hinges either, having actually used them on many RC models. Both trashy foof things and some honkin' stuff...
Chris, are you attaching Micafilm to structure with 3M 77 Spray Adhesive? Really works, you know.
For those considering trying Micafilm, make up your mind in advance that while (maybe) you can seal the overlaps it will take more skills than you bring to the party. That's why every single piece of Micafilm on my models has MonoKote lapped over and onto the fields of Micafilm.
Danny Dirt
You may well have gotten the laps sealed, but I have no faith in them staying that way or even staying clean.
Fuel dissolves most glues, including Balsarite. Even without fuel there is a problem in merely handling the model. At one time I had a Sagitta 600, a Sagitta 900 and the monstrous Sagitta XC, 14.5-foot wingspan glider. All were covered in Micafilm, fuselages painted with lacquer. Just handling the models tended to, over time, frag the overlaps at tips, TE, etc.
My advice would be to seal all overlaps with strips of clear MonoKote. Sure, upon close inspection you'll be able to see it, but for anyone with a model such as the one described in latest Stunt News most anything will be a step up for you.
Danny Dirt