Monokote Wrinkles-Time to return the wings & Stab before and after wrinkle correction - RC Groups
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Aug 15, 2011, 08:56 AM
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storm2313's Avatar

Monokote Wrinkles-Time to return the wings & Stab before and after wrinkle correction

Guys I posted this to show what I encountered from my Great Planes Cap 580 .46-.60 ARF. This is where I believe I should return the wings cause these are beyond taking out.

Please give me some opinions cause I'm used to removing wrinkles in covering, but on sheeted foam wings it looks like they never adhered it properly to the wings and stab. (I didn't take pictures of the stabalizer, but it's the same thing with it except the parts are smaller of course)

I'm going to call Great Planes today. Have any of you encountered this before?
Last edited by storm2313; Aug 23, 2011 at 04:21 AM.
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Aug 15, 2011, 08:58 AM
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Yep, looks like somebody at the factory went over it with an iron when they should have used a heat gun.
Aug 16, 2011, 10:12 PM
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43851E's Avatar
I've heard of folks receiving new parts and NOT having to send the bad ones back. That would be super cool! And a heat gun WILL get those out, just seek someone that has done it before if you don't feel you have the experience after you arrange for replacments and don't need to send them back if you're lucky enough. Also you mentioned that the Monocoat was not adheared to the balsa. This is an interesting comment. I remember discovering that with the superior way to shrink Monocoat was to first attach the sides & edges with the iron, then start in with the gun. Now on smooth surfaces, the iron does make the film "glue" itself to the surface you're putting it onto, but when you use the heat gun, it lifts off. This does two things, shrinks the devil out of it and releases the glue from the surface which gives it a very nice glossy look. No longer can one really see the pattern of the substrate it was ironed to. So finishing with the heat gun is not so bad, actually my only last step. Enjoy you're new Embry! Doug
Aug 19, 2011, 10:35 AM
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storm2313's Avatar
I went over the wings today with a new Top Flight heat gun and whats funny is most of those wrinkles got much smaller and in some spots were removed.

The thing is I just can't seem to make the monokote shrink fully.
Is there a specific temperature I should shoot for to get it drum tight?

I know sheeted foam is very difficult to reshrink fully.
Aug 19, 2011, 11:19 AM
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LesUyeda's Avatar
A problem that I have ran (run?) into in the past, is that if the humidity was high in the local that the covering was applied, then the structure moved to a local where the humidity was low, the wood dries out, and shrinks. I once built a "camper" shell for my truck; used commercial aluminum siding, intended for campers; I live in San Diego, maybe 5 miles from the ocean. Relatively high humidity. The first trip to Nevada, desert, dry as bones; the aluminum siding wrinkled in the "hard plane", from front to back, not along the corrugations.

Aug 20, 2011, 09:30 PM
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DGrant's Avatar
Originally Posted by storm2313
I went over the wings today with a new Top Flight heat gun and whats funny is most of those wrinkles got much smaller and in some spots were removed.

The thing is I just can't seem to make the monokote shrink fully.
Is there a specific temperature I should shoot for to get it drum tight?

I know sheeted foam is very difficult to reshrink fully.
Climate does play a part in making and keeping film covering from wrinkling...

The specific temp would probably be "just before you melt it" for a drum-tight finish.. totally doable really..but the iron has to be that hot. If its true/real Monokote it will take the heat very nicely.. the easiest way to do it is have a test strip or two, take the iron up to "melting" point, then back off a tad.. and whatever you do..don't let your "hot" iron linger over the plane..just get the heat to it and back off.. hopefully that will take out those nasty wrinkles... yes..thats one of the worst I've seen from them.. and its probably due to shipping, and climate changes.. Good luck with your plane.. it should look pretty sharp when your done.
Aug 20, 2011, 10:35 PM
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storm2313's Avatar
Well I tried something that seemed logical and it worked perfectly.

I adjusted the 21st Century iron to 350 degrees with no covering sock and used a paper towel with ice water to cool the covering pretty much instantly after applying the iron for maximum cooling.

It worked perfectly!! I read some articles on letting Monokote rest after shrinking well I believed it was to let the covering readjust to its surrounding ambient temperature. Well the ice water increased the process.

After applying the ice water I dried the area and would hit it fast over again if required. The results are a wrinkle free finish I'm truly amazed at.

I'll say this Monokote's maximum shrink temperature is 340-360 degrees, from my Raytech digital laser temperature gauge. After adjusting the iron to ths temperature you literally had to wait 6 seconds to see the covering slightly bubble as I pressed it down with the ice water paper towel.

I have to say I never continue to learn no matter how long I've been in this hobby. I hope someone else can benefit from my method it works excellent.

I will provide after pics to show the difference it truly is amazing.
Aug 21, 2011, 12:47 AM
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Off topic, but I couldn't help but notice the school name on your panels. Do you go there? I will be there on the 24th for orientation.
Aug 22, 2011, 03:50 AM
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It's the models trim scheme made to resemble Matt Chapman's scale model.
Aug 23, 2011, 04:20 AM
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Heres the after pictures as promised..

This is after pics using the method I described above in previous posts.

Thy look as smooth as glass.
Aug 23, 2011, 05:59 AM
An itch?. Scratch build.
eflightray's Avatar
The proof comes when you have the model out at the field on a hot sunny day.

Some builders use a 'pricking' tool to make tiny holes in the covering to allow any expanding air to escape. It tends to stop those annoying blisters.

I covered a balsa sheeted model in film many years ago that blisted badly on sunny days. On contacting the film manufacturer, they said it was all my fault, (naturally), for using too hot an iron. They said film should be heated just enough for the adhesive to go tacky then rubbed down with a cloth, never rubbed down with a very hot iron.

I still ignore them and do it as I want, but do 'prick' the film.
Aug 23, 2011, 08:15 AM
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storm2313's Avatar
Well here's what I know to be true about Monokote. First of all your temperature of the film itself is critical for the best results. The iron temp will always measure hotter than is required to make the film adhere or shrink. Measure the film temp after iron temp to see the actual results your going to get when your iron or heat gun is applied. The pricking of the bubbles with a number 11 exacto blade is the correct choice to allow the trapped gases to escape. Press lighly and puncture in the area with gas trapped multiple times. It will work flawlessly to remove the bubble syndrome.

Figure it like this, if the iron's at 350 degrees the film needs to be at around 320-335 degrees to get maximum shrinkage safely in 4-6 second bursts I measured it with a digital laser Raytek thermometer. To make the film adhere properly you still need the film temp at the minimum of 200 degrees for tacking to a structure. Once again I used the Raytek for a measuring device of the film temp not the iron.

Like I stated in the previous post when I explained overshrinking by cooling the covering past ambient temperature to get a little more shrinkage and then let it slowly come up to ambient temperature to avoid the loosing of the tight finish. When you apply the covering this way it's difficult for it not to adhere to the structure due to shrink wrapping application of the adhesive on the covering.

Once you shrink and adhere the film with the proper film temperature to the structure the only way you could get blistering is if the structure wasn't prepared right from the beginning. It should have been sanded smooth and removed of all dust and particles prior to attempting to adhere the covering. Like painting a car or structure.

As far as seeing if it will wrinkle or blister in the sun I live in Florida (Heat and Humidity are far exceeding past normal here than in England) where our average humidity is 80% along with summer temps in the direct sunlight averaging the low 100's. I feel secure in the finish shown and the procedures I implemented that the covering won't blister.
Jun 17, 2013, 03:37 AM
Rekitter of fine aircraft
Sxn McM's Avatar
Yes, this is an ancient thread, but the info is so important that I needed to unearth it for others. I'm working on a GP Reactor Bipe now and it has the most beautifully designed, and most horribly executed Monokote I've ever seen. My wife sent me to the hobby shop with a gift certificate as an anniversary present. I wanted a biplane I could fly at the neighborhood park, and the choices were the E-Flite Ultimate 20-300 (which I will have someday) or GP Reactor. The Reactor's green and purple trim scheme sold me. Those are my wife's favorite colors.

So I got home, carefully pulled everything out of the box, and discovered more wrinkles than a waterlogged octogenarian. I've never seen wrinkles this bad, even my first Monokote job, done in 1988 when I was 14 and consisted of the same purple as the Reactor, was better than this. The heat gun did nothing. The iron did little, and I was a bit gunshy after pulling a few seams on a 3DHS Extra, so I was about to give up, strip the airframe, and recover it.

And the. I found this thread. The cold paper towel trick has been working amazingly well. I have many hours of work left to get things looking right, but this thread is saving this project. Thanks a ton for the info.
Jul 14, 2013, 05:44 AM
Rekitter of fine aircraft
Sxn McM's Avatar
An update to that last post. All but the fuselage was covered so poorly that I got hold of GP and explained, and they sent another kit so I could mix and match parts until I had a good set. The new fuselage had a hole drilled wrong, but I managed to get the first fuselage to work. It took a ton of work, but she looks half decent except for a wingtip. I'll likely patch that with some matching Monokote soon.
Jul 19, 2013, 05:46 AM
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9XTremist's Avatar
semi-off topic, (but like you said, it's old)
of all the things i've heard about gp's balsa planes like coverings, heaviness of the wood, auw etc... from this thread and others it does sound like their customer service tends to not have a problem sending out parts and even whole planes to rectify a problem in a new kit. i do like using part of their electric 3d series planes 'hardware kit' on my scratchbuilt foamies.

michael clyde

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