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Covering This Wingtip??

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Covering This Wingtip??

Old 04-03-2015, 06:18 AM
  #26  
bjbellino
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What I am saying is if I take a piece of monokote say 6" by 3" and touch it with the iron and get it to shrink before it is adhered to an area where I would like it, when I do get all the edges stuck down and try to shrink it with the heat gun or iron, it will not SHRINK as much as it could have, because I shrank it before the edges where adhered. So if I go around the edges and stick it down and not heat up the main body of the monokote, I will be able to get more shrinkage because I haven't partially shrank it already, Bob. If you read the instructions that come with the roll, somewhere it used to say that Monokote is tri-axisually stretched when it is made so that when it is heated and shrunk it shrinks evenly. For the most part, all I am saying is that Monokote will only shrink so much, so if you heat this piece and start shrinking it before all the edges are stuck down, you lose a small bit of shrinkability, which in this case the area is really small and you need all you can get. Directions also say when covering a wing panel, smooth out the Monokote and seal all the edges securely and the start shrinking, so covering will pull tight over the full panel. That is why you do not adhere covering to each wing rib bay, because in so doing, the covering can only shrink in this small area and not the whole panel, Bob.
Old 04-03-2015, 07:38 AM
  #27  
CModel
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I have to say thank you for all your suggestions, but I've tried working the MonoKote almost going through an entire roll. A tip with this many compound curves is very difficult, and while talking about tacking ,and shrinking the covering when it adheres sounds plausible I simply am left with to much covering at the leading edge. If I try not to shrink the covering, and simply attach it then the amount of excess becomes even larger. MonoKote only has an available shrink of about 10%, so I'm not saying it can't be used on these tips, but with an investment of how much "trial, and error time"?

I'm about to buy some Ultra Coat, and give it a shot. I have researched their site, and they offer some outstanding instructions for download on Oracovers website. They really explain in great detail about using the two temperatures one to adhere, and one to shrink. They also explain that the covering when shrinking at 300 degrees does so in percentages easily exceeding MonoKote.
I know it's been a long time debate as which covering you prefer, but that's a very hard detail to overlook considering how much time it saves, and error correction is as simple as heating an lifting the covering without fear of the color being left on the model.

Check out the chart I attached with Ultra Coats details on its ability to shrink. MonoKote simply doesn't offer that. You must apply MonoKote virtually wrinkle free from the start, or you risk locking them in place.
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Old 04-03-2015, 09:20 AM
  #28  
jester_s1
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If you will do what I described, you will get a smooth finish. The trick is to stretch it along the line where you are attaching it to the existing covering. That will pull the wrinkle out of that tight compound curve at the front. It won't pull all of it out, but it will pull it enough that a secondary shrink will finish the job.
Old 04-03-2015, 09:58 AM
  #29  
CModel
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Originally Posted by jester_s1
I've done a repair like this before. It can be done in one piece of covering. The trick is to use your heat gun for application and stretch the covering at the same time you are shrinking it. Iron the covering down without shrinking it on the flat part of the wing, stopping where the curve at the leading edge starts to tighten. Then you can pull on the covering at the front to stretch it as you use the heat gun to activate the adhesive. That will pull most of the wrinkles out of that annoying section between the spar and leading edge on the wingtip. Then use the same pulling technique to adhere the covering to the edge of the wingtip by wrapping the covering around and pulling from the bottom while heating the top. You'll need to aim the heat away from the first seam you made, so you'll need a glove to protect your hand. Once it's stuck all the way around, you can keep using the heat gun to wrap the covering around the radius of the wingtip. The last step, if needed, is to use the iron at shrinking temperature to shrink out any looseness that remains over the open structure.
Jester,

I'm trying to envision what your describing in my mind. I have stretched MonoKote to apply it multiple times, and one thing I know for certain is that when you stretch it you distort it. If I stretch the covering towards the leading edge while its tacked to the flat area of the wing the seam from the new piece of covering will distort, and no longer be straight. It's like stretching pin striping you can stretch it, but the stress on the material makes its line uneven. Maybe you could do it as I'm certainly no expert, but I believe the real issue here is the amount of shrink I have to work with. The leading edge taper is tight with a radius bend as well. I thought even pulling the covering diagonally towards the leading edge while being heated would work, but I simply can't produce the amount of shrink required to tighten the covering, while pulling, and trying to keep the covering from attaching itself to the wing to soon.

Honestly it should never be this difficult. It could very well be my technique, but judging from all the hundreds of posts on how difficult this covering is to work with I might as well try Ultra Coat. I've spent at least 6 hours trying to accomplish two wingtips, and could have literally built a new wing in that amount of time. I think MonoKote is fine for flat surfaces, and typical wingtips where the compound curve isn't quite as extreme. I had no problems applying it to other surfaces, it's simply not modeler friendly in this case.

A roll of covering for $16 is well worth my time, and effort to see if it's a matter of skill, or product.
Old 04-03-2015, 11:22 AM
  #30  
Gray Beard
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Not all Mono will shrink at all so it may be the covering itself. Have you tried starting at the leading edge first and moving the covering from front to back? It may help but if you have a roll that isn't going to shrink there really is no good answer at all. Last time I bought a roll of Mono it was for a students new plane. The kid spotted a plane at an IMAC event that he fell in love with so I had him take a photo of it so we could cover his kit built plane just like it. The plane had a lot of a green in it and sure enough the green we had wouldn't shrink. This was on an open bay wing no less. Sometimes it's no an operator problem. There are several colors that are made by all three manufactures that are a good color match.
It just sounds more like a product problem then anything else.
Old 04-03-2015, 12:24 PM
  #31  
CModel
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Gray Beard I totally agree with you. I think its a product issue. I'm going to post my results with Ultra Coat when I get it. Thank you for your support. I've read many threads on how user friendly it is, and like you wrote earlier there really isn't any tricks required it simply does what its meant to do.

Last edited by CModel; 04-03-2015 at 04:01 PM.
Old 04-03-2015, 04:11 PM
  #32  
Gray Beard
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Mono used to be like that, I started using it in the 60s when it first came out. Used my mothers iron until I got caught!! About 15 years ago they changed the formula and it sometimes works very well and sometimes not at all. That's when I tried Ultra and never went back.
I enjoy covering, I find it relaxing and don't feel like it should be work or have to be manipulated too much. I do need to do a few things differently then others but it is due to the climate here, really can be hot and it's always dry so I cure the Ultra before I put on the trim. I covered my last two builds during the winter or late part of fall and it wasn't hot enough to cure the covering. It has been warm here already and I took both my new planes out when it was close to 90 and so far I haven't gotten a sag or wrinkle in this Chinakote from Hobby KIng. At half the price and a 5 meter roll I really am sold on the stuff. It's even easier to put on then Ultra.
Old 04-03-2015, 04:21 PM
  #33  
Gray Beard
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This is just a photo of before and after on an elevator half using the Chinakote. It is on a 90 inch span plane with a big cord and I did the yellow with one roll and had some left over. I never used my heat gun to shrink the covering at all. The covering may be in the build thread? Prime Cut +20 in kit building. I don't recall if I showed the covering or not, maybe??
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Old 04-03-2015, 06:25 PM
  #34  
CModel
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It's amazing at that price. I look forward to trying their brand as well. I research all the components I buy from China, and honestly haven't been disappointed in any. Clevis's, pushrods, carbon, all have been excellent, and cheaper than typical stateside prices.

The first pic looks almost perfect even prior to shrinking. It looks like you just touched it up on the second after pic with a slight shrink, and no need for a heat gun. I'm personally not a huge fan of the heat gun as I feel I can control the exact heated area with my irons.

Excellent work!
Old 04-04-2015, 07:55 AM
  #35  
dirtybird
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Hobyhing stocks chinacoat in their USA warehouse so you dont have to go to china for it.
Hobbyparts carries it under a different name as does several other importers.
I am done with monocoat.
Old 04-04-2015, 08:34 AM
  #36  
Gray Beard
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I buy everything from the U.S. warehouse too. I don't buy very much of anything from HK and other then a roll of covering I haven't ordered from them in about two years. Then it was just items for my electric plane. The prices can't be beat but there is no customer service and shipping will kill you. We have a group of guys here that ordered a lot from them so everyone got together and placed one big order.
The covering is usually in stock here state side and shipping is cheap plus it is in your hands in about three days.
Old 04-09-2015, 01:44 PM
  #37  
CModel
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Gray Beard, your were dead on. It's the covering. I will post my results shortly. Oracover aka Ultra Coat is almost to easy to use. I practiced with a small piece to see how well it shrunk, and to get used to the glue adhesion. I can actually feel the adhesive unlike MonoKote, and the repositioning without the color bleeding is amazing. This is my first time using it, but Ultra is by far a better product.

I will post pics shortly. The wingtips didn't require really any special technique other than what I did when using MonoKote.

Thank you all for your support.
Old 04-09-2015, 02:15 PM
  #38  
Gray Beard
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If you think that is easy then Solartex will freak you out, it will make anyone look like a master coverer. The Chinakote is just like the Ultra but I haven't tried lifting it to see if the color stays on or not?
I read all the time how people manipulate Mono to get it to go on without wrinkles but yadayadayada, who needs to mess with it and why bother when there are better products on the market and for a lot less money.
Covering should be fun and easy, not work. At one time Mono was that way.
One thing is that you can't always find a color match for the Ultra. They used to have a very good paint that was a perfect match but we can no longer get it.
Old 04-10-2015, 02:36 PM
  #39  
CModel
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Grey,

This may sound odd, but now the only issue is I keep getting the color separating from when I shrink the leading edges compound curve. I can get it drum tight, and perfect, but around the edge of the tip it appears the covering is under, so much stress from shrinking its breaking the pattern of black, and white checkered Ultra Coat like color separation, but with no wrinkles. I'm not sure if I'm actually shrinking it to much, or missing an application technique. Other than the solid wood edge of the tip where the severe compound curve is at the leading edge the rest of the tip comes out perfect.

I'm not sure if I'm just splitting hairs, or if I can try a different method.
Old 04-10-2015, 04:07 PM
  #40  
Gray Beard
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Photos help but if your talking about some color squishing out the seam then just remove it with acetone or alcohol. I have never seen ultra separate as I'm seeing it in my minds eye. Are you overlapping the covering so it's being glued onto the other side or is it slipping off the wood as you shrink?
Your just covering the wing tips? You iron it down with an overlap then ironing it down to the outer wing tip wood then with your iron shrinking the covering? Covering sticks to covering the best, once they touch they are there until you pull it off. I just don't understand what problem your having.
Old 04-15-2015, 03:14 AM
  #41  
CModel
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Gray, I'm sorry for not posting sooner, but I got my problems ironed out.. as the picture reflects. I was using just a touch to much heat. I dropped the temp by 10 degrees as I tend to hold the covering to long while heating( learned from using monokote.) This film is so much easier to work with. When heated it becomes very pliable where MonoKote you typically have to work the wrinkles out with so much pulling resistance. Some wrinkles on the flat surface came out that I can't believe did. MonoKote with the same wrinkles, and you better start over cause there done.

Anyone reading this thread read all the suggestions about adding blocks of wood to the tip. I didn't do this. The only change I made was from MonoKote to Ultracoat, and the problem was solved. I can't imagine if covering a compound tip like this can be done how fast applying it to typical structures would be.


Overall money very well spent, and you wrote something very true. The finish on the model should be fun. I enjoyed working with the film, and taught myself a couple new techniques at least there new for me. I found tilting the iron on about 45 degrees, and using the edge to apply downward pressure on the film very effective for attaching, and getting the last of the wrinkles out.
This made me realize MonoKote should really only be used for trim, and that's what I plan on using it for.

The other huge plus when working with this covering is removal. If you need to reposition it simply apply heat, and gently lift. You simply can't do that with MonoKote without the losing its color layer. Trying to remove MonoKote is usually more time consuming then building a new part, and covering it literally.

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Old 04-15-2015, 02:22 PM
  #42  
Gray Beard
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Mono used to be just like that but those days are long gone but I still trim with mono when I have it on hand. I'm still using up what people give me, I haven't bought any in years. I try to also avoid the debates, the vs thing. Use what works for you but if your new to covering then I would avoid the mono. I can usually make it work though but the key word is work. Work is a four letter word! What your calling a big compound curve is really nothing and with the correct covering anyone should be able to do it.
I have no temp gauge for an iron and can't tell anyone what temps I run, I just test iron until I get it set where I like it.
The heal of the iron is also the hottest spot on the shoe so you can manipulate how you run the iron. If you like Ultra you would love the TEX coverings. It's even easier to work with. Now give the Chinakote from HK a try. Way less money too!!
Old 04-15-2015, 11:23 PM
  #43  
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Glad to see the OP got a solution. Just thought I'd throw in my $0.02 for anyone else facing this issue and not wanting to switch coverings for whatever reason.

Monokote can ABSOLUTELY make this curve. I had a nearly identical wingtip on an old Stik design a couple years ago. What I finally figured out with Monokote is that I have to work in very tiny areas at a time for shapes like this, and I must pull the covering quite hard as I work the iron, while simultaneously tacking down the edge AND shrinking the area at and near the edge to make it conform to the edge's shape. I end up with some minor wrinkles in the middle of the covering, but these area easily ironed out. Bottom line: as long as there are no wrinkles on the edges (that is, the areas you can't fix later because they are bonded in-placed to the airframe), the rest will iron out.

Monokote is very "shape-able"...think less about shrinking the covering and more about shaping it. On something like that wingtip, for instance, I will start by tacking down at a point that represents (roughly) the geometric center of the curve. In this case, that would probably be right at the front corner of the wingtip. I then start working the hardest parts (so, working forward), but I don't actually lay the covering completely flat before ironing: I deliberately put some wrinkles in the covering to take up the slack and prevent having a huge pile of extra covering by the time I am finishing the curve. The key is that the amount of excess covering I absorb as I go is not more than what I can smooth out with careful iron-work. This is achieved with gentle pressure as I pull the covering against the airframe, followed by firm iron pressure to tack it down...if you press the slightly-wrinkled covering hard into the airframe right away, you will get a bunch of permanent wrinkles. I am not working against the airframe at first, I am working against the pressure I am holding on the covering with my other hand. This forces the Monokote into a new shape before it is fully tacked down. By the time I get to the end of the job, all that excess covering that the OP was having trouble with initially, is now down to about the same manageable amount I've been absorbing all along.

I used a similar method on a Cub tail, but I would say it was actually harder due to the smaller working area, tighter curve, and concave shape of the final covering. I posted some pics in this thread:

http://www.rcuniverse.com/forum/kit-...-cub-tail.html

I have not used Ultracote since a small repair job I did on a plane when I was about 13, but I am interested in trying it again. My Tiger was originally covered in the stuff (by someone else) and I was impressed at how smooth it looked (maybe just the skill of the builder, I'm not sure). But, at this point I have not been in a hurry to switch from Monokote, since I am so comfortable with it.

I also wanted to mention that getting FRESH Monokote is CRITICAL. Recently, I had some really old stuff I got from a friend, and it was a nightmare. Dumping it and going to one of my new rolls made all the difference in the world. I am also aware of reports that Monokote's quality has been hit-and-miss in recent years, which is really unfortunate. Perhaps I've been lucky, or perhaps it's just the colors I use (typically red, white, blue, or silver), but I have had no such issues as of yet.

Matt

Last edited by dabigboy; 04-15-2015 at 11:30 PM.
Old 04-16-2015, 02:18 AM
  #44  
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Add another rib going forward, like the long one going aft, and your job will be much easier. Also make sure you have about 3 inches of extra monokote so you can grab it easily and pull it. Sounds wasteful, but it does help get the job done. I have to admit that I have punted in the past and put in a separate piece on touch curves.
Old 04-16-2015, 08:45 AM
  #45  
Gray Beard
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Well, that's one way to do it! Back when I was still using mono it went on and shrunk like Ultra does. I do question what to do when you get a roll of mono like the last roll I used, it was some special green and had no shrink to it at all. It was on a flat bay in the wing and even putting it down as tight as it would go you couldn't shrink any of the little wrinkles out of it. Then to add to it the green wrinkled and sagged in the hot sun so it ended up looking like hell compared to the rest of the plane.
Old 04-16-2015, 09:02 AM
  #46  
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I met a guy once who loved Monocote (couple of years ago). He said you basically have to get to almost meltdown temps to make it shrink right. But he still loved it. I guess the trick is that it requires much higher temps than Ultrakote or other types.
Old 04-18-2015, 08:30 AM
  #47  
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Dagbigboy's explanation is dead on. It took me a long time to figure out how to get monokote to stretch around compound curves. I use a trim iron for compound curves and do a little at a time. As Dagbigboy said, you have to stretch it by pulling fairly hard. I bought a 4" diameter round wooden ball from a craft store and mounted it on a dowel with a base.
I then practiced covering the ball with monokote scraps. I was able to apply monokote smoothly around 1/4 of the ball. If I tried any more than that, it would stretch too thin. I have found that different colors or different batches do stretch more than others, but I have not had a problem after I figured out how to do it.

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