Whirley Bird

My Feedback: (1)

I received the proper heat gun and was impressed with the way all the bad spots went away.
I notice that when i'm heating the covering everything looks smooth as glass.
After it cools down I do notice some spots that have what I call stretch marks.
No problem really because all the bubbles and very bad wrinkles never come back.
I just wanted to know if i'm expecting to much or should I keep the gun on those spots a bit longer.
So far I did 3 planes and haven't blown any holes through the covering.
Leave well enough alone?

Damnathius

Be careful... The heat gun will put a hole in the covering quicker than you can get the gun away. It is a rather instant process once the covering is too hot, and it is difficult to tell when it is going to happen.

I assume you're shrinking the covering on ARFs? It's a lot easier to get all the wrinkles out when covering the model yourself, but that's a different story.

If you have scrap material you can experiment by covering a piece of sheet balsa with a hole in it and seeing how long you can actually hold the gun in one spot.

Stick Jammer

Damnathius is right, be careful with the gun. If the covering had some bad wrinkles prior to using the heat gun, you may have to live with the "stretch marks". Even though you were successful in getting the covering smooth, bad wrinkles tend to leave a mark sometimes.

Whirley Bird

My Feedback: (1)

Thanks stick jammer & Damnathius
Yes this was on an ARF and an RTF.
The wrink;les were very bad and their all gone.
What I was doing was being careful with the gun and saw those super fine lines vanish.
Their so fine you have to really try to feel thoes spots.
They come back when the Monikote cools.(on the elevator ONLY)
If I showed you the wing I don't think you would notice the marks so maybe i'm being to fussy and expected to much from the reshrink.
The tail section was the pits.
Look at the tail section.
This is the worst spot on the entire plane.
But it's the only spot that come back in a day or so.
How can I keep it from returning?
Am I being to fussy?
The wing is now drum skin tight

Whirley Bird

My Feedback: (1)

Forgot to tell you this PIC was magnified X16

Damnathius

WB, it looks as if you have a sheet stab? When shrinking the covering on a sheeted surface, (stab, fuse, rudder, wing) you should put some pinholes (one or two) in the wrinkled areas before using the heat gun. What happens is the air inside heats up, and holds the covering away from the surface, then when it cools, the wrinkle comes back. This will also apply to smaller built up surfaces like stabs and rudders, that have little air space in them.

After it fits tight to the surface, go over it with an iron to stick the covering down.

Whirley Bird

My Feedback: (1)

OK,
I left UR post so you can refer back to it.
When I *HEAT* that part it goes away and leaves a very nice shiny smooth look.
A day later it comes back.
As for the wing I think because I heated the sheeted areas first,they loosened up and then I heated the rest of the wing between the ribs and that shrunk fast and pulled everything tight.++++++++++++++++++++++++++++++++++++++++++++ ++++QUESTION!!.
I have the iron.
But from all that heat is the glue on the covering still good?
My Girl is a nurse and can get me a small needle but what type of glue should I use?
I guess I can always inject some rubber cement and then squeeze the rest out?
The rest of the plane looks like a MILLION BUCKS.
That Monikote really shines

Damnathius

I wouldn't try to put any glue in it, as you'd probably end up with a real mess. As far as the needle size, just a sewing needle or small t-pin will work. The object is to let the air out as it's heated. If the wrinkle is coming back after a day, try ironing it down after you get the wrinkle out, which will allow the adhesive on the covering to stick to the wood, and might keep the wrinkles out.

You can only do so good on an ARF. All the ARFs I have messed with had some blemishes even after shrinking, usually around the edges due to mass-production type workmanship. The covering brand is also an issue. Some of the stuff they use requires some very high temperatures to shrink. Kyosho comes to mind here.

In the end it's probably impossible to make the covering perfect on an ARF, so the best you can do is pretty much all you can do short of recovering the plane.

birdnest

First off, the adhesive on the back of the monokote is still ok ,dont use rubber cement etc! Secondly, if you've heated it up a few times with the gun and the wrinkles are returning, it's time to take out the iron. If you don't have the coverite version, I recommend it. Use a sock over the iron. Set the temp a little over 300 with the coverite thermometer. There is an art to getting the wrinkles out, you cant just smash them down. Heat up the covering adjacent to the wrinkles first, and then move the iron away from the wrinkle to push the excess covering away and redistribute it. The last place to iron is the wrinkled area. If there is a bubble, now is the time to stick it with a standard pin, not a medical needle, then gradually heat around the area, moving the iron and the trapped are towards the pinhole.

Sometimes I get the covering too hot and it puckers or wrinkles up. I find if I wait a week, the covering relaxes and I can go over the area again with the temp down a bit and smooth it out.

The key is to understand that you can shift the covering around a bit with the iron and then adhere the covering to the wood so the wrinkles wont return

Peter

Whirley Bird

My Feedback: (1)

You Guys are great for all the help your giving me.
Yes,I did heat it several times.
OK on the pin hole and working around the bad spot and hit the bad spot last.
I printed all that knowledge out.Some very good info there.
No my question is about the iron.
What is the coverite version, ???
I have the TH iron but for the price I can afford another one to do the job better.
But is it the shape ?
Temp settigs?
I have socks and it does get very warm but like you said I went the wrong way.
I plastered it right on the bad spot first.
Just for info I posted a PIC of the TH iron.
How do I know what a corvettet iron looks like?

Damnathius

The Coverite iron has a better shaped shoe than the TH. I use a Global, which also has a better shoe shape, and better point than your standard iron. It's great for getting into tight areas like between control surfaces, etc. Once you get one of these irons, your TH will be relegated to the tool drawer forever. It will be almost as good as discovering the wonders of a heat gun.

Whirley Bird

My Feedback: (1)

.
Hi Damnathius.
OK I know what you mean now.
Since this problem is not in a tight area i'll go over that bad spot later with your instructions.
I'll leave it sit and snap another picture of it tomorrow and let you see how it came out.
When you have time let me know where I can get one of the irons you listed.
The one wing was so bad I sent TH a picture of it because they said since I put the plane together they considered it used and non returnable.
The wing had enough wrinkles to make a bag of prunes look good.
Tower Hobbie after seeing the picture sent another wing and told me to keep the old one.
A blow dryer didn't do well nor did a regular iron with terry cloth on it so I went for the TH combo Iron and Gun.
When my Girl saw the old wing she said *YOU HAVE TO BE KIDDING*
The wing cam out 99.9% A-1.
2 tiny spots that are there but flush.
I would have to point them out to you.
Thanks for all your help and suggestions.
I'll keep you posted and send a PIC tomorrow.
Have a nice Monday

birdnest

There's nothing wrong with the tower hobbies iron but the coverite one heats up quicker, has a nicer shaped shoe like he said, and is just a quality tool. You will like it. Get the little coverite thermometer while you're at it, it runs about $7 I think. Both are available at tower i believe. For now, use your tower iron and take your time and get your monokote technique down.

Peter

Whirley Bird

My Feedback: (1)

OK Peter and Damnathius,
I really appreciate all the info you Guys supplied.
I'm warming up the iron now and getting ready to make the tail section flawless.
Also thanks for the tip on the thermometer.
Sound like you guys been doing this for a long time.
So far I have the heat gun set to max and been lucky.
I saw the covering between the ribs start to flutter and I backed right off.
So far I haven't blown any holes. WHEW, Came close though.
Well Miss Nursey comes home in 3 hours so i'm going to start now.
Look for a Picture tomorrow.
First puncher the bad spots and go from there.
I printed everything out.
Many thanks.
Have a great week

Aerohead

My Feedback: (37)

Another thing you have to watch out for when using the heat gun, WB. If you direct the heat from the gun too close to where the covering is lapped over itself (the seam), you can get the covering to draw up so tight that the seam slips, and will eventually pull loose. This is pretty easy to do. What happens is this. You see a place where the covering has some wrinkles, so you apply heat to shrink it out. The heat draws it up tight, but when it cools again, it wrinkles. So you apply heat again. The same thing happens again. What happens is, when a lot of heat is applied it shrinks the material, but, at the same time it is heating up the seam enough so that the adhesive between the bottom layer and the wood, and between the layers softens. This causes the two layers to pull apart just enough to let the material wrinkle again. When you reapply the heat this happens again, until, eventually the two surfaces pull apart, leaving an ugly gap. This happens especially easily with Ultracoat. So watch out for this when you are tightening already-applied covering, especially at the edges of wings and control surfaces.This condition is almost impossible to repair once it occurs without leaving ugly-looking places on your covering job. Remember, any place that is left uncovered (bare wood) lets the oil from glow fuel penetrate the balsa, which, in turn accelerates the loosening of the covering even more. This is not to discourage you from tightening your covering. You just need to take it easy for awhile until you begin to get a feel for it, and don't expect perfection right away. It takes a little while to learn the ins and outs of covering with this stuff, but you'll get the hang of it pretty soon.

Damnathius

I think the Global iron is carried by Hobby People as well.

Good idea about the thermometer too. Different coverings have different tack and shrink temps, and going at a covering with the iron full throttle could be a mistake and ruin it, or shrink it beyond what you need, which can eliminate the possibility of future touch up shrinking.

Aerohead also has a good point I will add to. When first considering shrinking the covering on any plane, go over all the edges with your iron to make sure they are well stuck before attempting the large area shrink with the gun. Often they are not as tacked as they should be from the factory. Although this is not a 100% prevention for pulling the edges loose on close lapped seams and leaving a gap, it will help a great deal.

The "flutter" sound you heard is common when using a gun and the covering is loose, and not an indication of burning through.

Oh, did anyone mention to keep the gun moving? As birdnest pointed out about using the iron AROUND the wrinkle, also use the gun AROUND the wrinkle first, as this will often eliminate the wrinkle without even focusing on the wrinkle. Keep it moving to heat the covering as evenly as possible. This way if one spot has run out of "shrink" capability due to overheating, such as a bad wrinkle, it's possible the covering around it will pull it tight.

Good luck with it, and let us know how you fare.

Dave

John Wells

My Feedback: (10)

About one month ago, I purchased two new rolls (14 feet) of white Monokote from the LHS. They were the "seven for six" rolls. I've been using the heck out of that stuff for 24 years. The new white Monokote reacted to heat very much like Ultracote, only worse. I couldn't burn a hole in it. When I beared down on in with a TopFlite heat gun, it just sagged away from the gun. I couldn't melt a hole in it with my Coverite iron, even if I left it on high and sat the iron on it for 10 seconds. Folks, something is definitely different. If one doesn't tighten the stuff up real well before trying to shrink it over an open bay (like a wing rib bay) you aren't going to get it tight. Both rolls had the same characteristics. Monokote was always the covering we could depend on. I can't imagine what the manufacturer was thinking when they changed it. I wrestled with trying to get the covering on the wing tight. It still has something to be desired and it's not as tight as I would like it.

I emailed Topflight / Great Planes / Hobbico customer service with a very polite question about it and was completely ignored. Have any of you all experienced the difference in Monokote? If all colors are going to react this way, I'll stay a mile away from it and find an alternative product.

Thanks for any information you might have,

JW

JimTrainor

I've read numerous times here on RCU that Ultracoat is pretty good compared to Monokote. I've also read people's accounts of monokote being different recently. Is top-flite quietly changing their product in response to Ultracoat's popularity??

Whirley Bird

My Feedback: (1)

The only thing I can say is that they may be using the same material that people buy that comes folded up and opens up to a full size tarp/
You pull it over anything thats stored outdoors for the winter and then use a very hot gun to shrink it.
The stuff is really tough.
Speaking of different materials,
I found the hard was that the colored trim they place on top on the white monikote must be different as I have created bad heat spots on it. Then on my Avistar it never bothered any of the trim.
I don't have the problem you have with getting the covering tight.
All 4 of my planes are *VERY* tight.
MonoKote will take more heat then the others but I think yesterday I almost blew a hole between 2 ribs.
The covering was being pushed in and then it got very soft with no warning and I pulled the gun away.
Look at my picture below.
Why the small cannon on the wing?
It's sitting between 2 ribs and weighs just under 3 pounds.
Look at the rib on the other side of it.
You can use this wing for a drum and I have the Guys above to thank and walk me throug,along with full page instructions.
This is the wing that was so bad I sent a PIC to TH and they replaced it.
Now with the help I received here I have a 100% flawless wing.

Whirley Bird

My Feedback: (1)

This PIC is a bit dark but notice the ribs and how tight the MoniKote is.
See that root section.?
It was at one time wrinkle hell.
Look at it now.
The whole wing is free of bubbles and wrinkles and drum skin tight

Whirley Bird

My Feedback: (1)

Hi Jim,
I have no i'dea what is going on in the shrink plastic industry.
Frm what I read the ultracoat can't take the abuse that MoniKote can but Monikote if thicker hence a good material for trainers.
Then you have TowerKote but i'm sure it's some other brand.
Like there Radio System 3000 is made by Futaba.
Anyway this my first time working with a major job with Monikote and it came out great.
You have to know what your doing.
Thanks to (Damnathius)(Aerohead)(birdnest)&(stick jammer) for all the information they supplied.They also gave me some additional p[ointers and i'll be loading up a PIC of that tail section tonight because i'm allowing 24 hours for that fix.
So far what they told me to do is still holding up
DO IT RIGHT AND DO IT ONCE

Aerohead

My Feedback: (37)

That looks just great, Whirley Bird. Glad we could help you. Of course, there will be alot of new challenges when you start doing all the covering on your own, from scratch, especially around curved wingtips, but you seem to be off to a really good start. Anytime you need anymore help, just yell. We'll be here.

Whirley Bird

My Feedback: (1)

Aerohead,Look at this pic.

http://www.rcuniverse.com/attachment...&postid=761956

This is from last night.
I followed the instructions you Guys gave.
=========================================
Now look at the picture after I did what you guys told me to do.
I know there is a tiny spot but this PIC is magnified 16 time bigger.
Copmpare it to last nights picture also at 16 times bigger.

Whirley Bird

My Feedback: (1)

It's a shame there is no way to upload a full size PIC so I took a PIC of the tail section.
The rest of the plane looks just as good not a bubble or wrinkle in sight.
What may look like wrinkles are light reflections.
The rest of the plane looks the same.
When I was heating the stab with the iron I heard the Monokote make a plucking sound several times.Good indication it WAS SHRINKING.
Again many thanks to to (Damnathius)(Aerohead)(birdnest)&(stick jammer) for all the tips and suggestions.
If I run into a MoniKote problem I know who to contact.
Thanks to you Guys I now have the right tools and a slik looking plane

Damnathius

Glad it's working out for you WB.

Ah, Aero mentions wingtips! They can be hell if you don't know how to do it, and a relative breeze once you get the technique down. But that's a future lesson in heat, elasticity and burned fingertips!

Oh, the places where there are multiple layers of Monokote... You gotta figure you are trying to shrink a dual thickness, and it will most definitely respond differently to the heat you apply.

I haven't had any problems with new Monokote not shrinking up, but that might be because I get it as tight as possible while tacking it. I did blow a hole in a .25 Cub I had about 7 months ago by holding the heat gun on it too long. Lesson learned there!

Anyway, good to see you're getting the hang of it. It certainly makes the hobby more rewarding.