Monokote/Ultracote secrets
 

I would like to start a thread with Monokote/Oracover secrets that you have learned over the years. Hopefully these lessons can help newer builders. The idea is not to show how to cover but a trick or two that you learned. Keep it simple and short. I will start with a few examples.

1. Get the right tools. Sharp blades, a standard covering iron, trim iron and heat gun are all a must for a good covering job. Also an iron sock is a must if you dont want to scratch the finish.

2. Touch the covering as little as possible and use as little heat as possible. Also, dont use pressure, let the heat do the work.

3. Work in as large an area as possible, meaning, try to cover entire wing halves, fuses, etc with one piece and then add your accents on top. I find that the fewer pieces of covering the less places for wrinkles to appear at joints.

4. Use Oracover!

5. When shrinking down open bays with the heat gun shrink down the outside seams first and then work your way in. If not wrinkles can develop in the corners.

6. Clean your planes with a soft cotton rag and not paper towels. The paper towels will scratch your finish.

7. Cover from bottom to top and back to front.

8. When covering a wing, cover both sides before shrinking with the heat gun. Then when you shrink work on one side a little thin flip the wing and shrink the other side, constantly working back and forth. Never shrink an entire wing side by itself, the wing will warp... dont ask me how I know.

9. Be sure to put a damp paper towel or rag over seems when shrinking with the heat gun to keep the seams from pulling.

Add your tips... remember to keep them simple and short. I am sure we will all pick up something new.

RE: Monokote/Ultracote secrets
 

Great thread!

One learned from a Monokote demonstration years ago ...

While you are laying down the covering, pull it VERY TIGHT. As if you not be able to shrink it. The results were amazing.

Bedford

RE: Monokote/Ultracote secrets
 

I really agree with #4.
This weekend did some repairing/recovering with Monocote and Oracover.
The Oracover results were much better.
Admittedly, I'm a newbie at covering but I'm not buying Monocote again.
Good Luck,
KW_Counter

RE: Monokote/Ultracote secrets
 

I am covering a profile and on one side of the ailerons I used transparent monokote and the other side is transparent oracover. The Oracover is perfect and took just a few seconds to shrink out the wrinkles. The monokote looks OK but I definetely had to work with it more and it still has a few fine wrinkles in it.

RE: Monokote/Ultracote secrets
 

This is from RC Hobbies.org and is a nearly perfect explanation of how to correctly use Ultracote. There used to be an explanation for Monokote, but over the last 4-5 years it is hit and miss with application tempatures that change with color, bad rolls, mismatched color, seperrating color layer, and generally a pain in the ***** to work into a perfect finish. (didn't used to be) So I have found myself using Ultracote. Very dark colors will bubble up in the hot direct sun if you don't pre stretch it. AKA... you need to stretch it on, not stick it, then shrink. But atl east it's quick and easy to remove any bubbles. I want to know who the genious is, that decided to use a bonding layer on Monokote that actually creates gas when hot...


Here's the tips...

RC Airplane Covering Tips
Getting that Great Looking Finish
A beautiful, professional quality finish adds that all-important final touch to your model. It's what gets those extra stares at the field…and makes you proud ofa job well done. Some expert builders would have you believe that covering is an art that takes years of experience to develop, but the truth is that you can achieve it with some basic know-how and patience. Understanding the materials you're working with is vitally important, and, surprisingly, this is where many modelers make the biggest mistakes. Each brand of covering has unique properties. So if you learn using one type of covering and then try using those techniques with a different brand, it often leads to marginal results. I've been using UltraCote exclusively for the last 15 years. UltraCote offers several unique properties that are advantageous over other film coverings, making it easier for me to achieve and maintain a professional finish. Applying UltraCote requires its own learned techniques.

Multi-temperature, Maximum Control

UltraCote is unique in that different things happen at different temperatures. This allows for precise control during covering.

Covering with UltraCote becomes many times easier– with vastly improved results – when you understand what specific temperatures do to UltraCote, and when to use those temperatures.

220°F-Application

The adhesive is activated at just over 200º F. At the recommended application temperature of 220º, the adhesive reaches its full bonding strength. No shrinkage of the film occurs, so no distortion of the film takes place. Use the 220º application temperature when applying covering and when applying UltraCote trim pieces over UltraCote. Remember, if your iron is set at 220º, no shrinkage or distortion will occur, so there is no riskof distorting seams, trim lines or trim pieces and full bonding strength occurs.


Watch out for…

Don't press! Heat liquefies the adhesive, not pressure. Let the heat do the work and avoid gouges. It's natural to want to apply pressure, but it doesn't affect the bonding strength. If you're using a sock (highly recommended), it will be necessary to go more slowly over a given area, as it takes longer for the heat to penetrate the material. Some modelers turn up the heat to 240º when using a sock, but I prefer to stick with the 220º temperature and go at a slightly slower pace. This creates fewer air bubbles.

300°F- Shrink Onset

At 300ºF, UltraCote will begin to shrink. Use this temperature after the covering is applied to tighten it, remove wrinkles and remove imperfections. It's amazing how many wrinkles can be removed at this temperature, and it's important to start removing imperfections at this minimum shrink 300º setting. UltraCote features a unique property that allows for a controlled shrink rate based on the selected temperature. While it begins to shrink at 300º, at 320º, UltraCote shrinks 18% of its total shrink rate (see chart). It's important to use the minimum temperature necessary to achieve a smooth wrinkle-free finish. Most modelers don't realize that to further shrink most brands of film covering, it must be heated above its previously exposed peak temperature. In other words, if a covering was already exposed to 320º, it will be necessary to go above 320º to further shrink the covering. Use the lowest temperature possible to achieve a smooth wrinkle-free finish at the start and you'll have the largest available shrink rate remaining, should you later need to shrink the film.


Watch out for…

Stay away from seam lines and edges! Remember, 300º is well above the adhesive activation temperature, and seams will pull away. If you have some stubborn wrinkles close to the seam line, try this trick. Soak a washcloth in cold water, then fold it twice and place it on the seam line, covering the seam but exposing the wrinkles. With your iron at 330º, quickly apply it to the wrinkled area (about 5-10 seconds). The washcloth will keep the seam cool, and prevent it from pulling apart and distorting.

350°F- Maximum Shrink
At 350ºF, the maximum shrink is achieved. You won't use this setting very often, but it's important to know the total shrink temperature range. That's because the amount of shrink rate you'll have left is based on the temperature you use to shrink the covering.

For example, if you're shrinking your film using 320º, by referring to the chart, you'll find that 82% of the total remaining shrink is left. That's good! That means that, if in the future you need to re-shrink the covering, it won't be a problem. But a word of caution: use the highest temperatures only as a last resort to shrink wrinkles and imperfections. In most cases, if you need to use this much heat, you'd be better off to just replace the covering with a new piece.


Watch out for…

Stay away from seams and edges. This high temperature can cause bubbling and blistering.

Removing UltraCote®

You may come to a point when you'll need to remove or replace a piece of UltraCote.

In many cases, the covering will simply pull away, but if you're having a tough time, use your heat gun. Lift a corner of the covering, and then pull away while directing heat in the area to be removed. I just recovered the 2-year-old Reebok CAP 232 using this heat gun technique, and it looks as good as new!

Bubbles and Blemishes
When your airplane sits out on a hot sunny day, you may notice that the covering bubbles and wrinkles. This is common with all brands of film covering, no matter what the manufacturers claim. But getting rid of those wrinkles is easy. You'll need a heat gun, a covering mitt, a wet washcloth, and a fine straight pin.

Heat the affected area, and notice how the air underneath the covering expands, making bubbles. As you continue to apply heat, moving in a 6” circle, it will release the adhesive bond. At first, several small bubbles will appear, but as you continue to work the area, the bubbles will join to form one large bubble. Now pop the bubble with the pin, and immediately wipe the area with a covering mitt to reattach the covering. It may take several attempts, and you'll get better after you do it a couple of times.

It's important to not stay in one place for very long with the heat gun, especially if you're working with a balsa-covered foam part, as warping and damage could occur. If the affected area is close to a seam, use the wet washcloth trick to prevent the seams from distorting and pulling apart.

Preventing Heat Blemishes

Heat blemishes occur when the elevated temperature causes the trapped air in the wood to expand. With nowhere to go, the expanded air causes a bubble to form in the covering and stretches the film. When the air cools, the stretched covering remains. You'll notice this happens especially with dark colors like black or dark blue, and that this never happens on the bottom of the wing, but only the top where the sun heats the surface.

The solution? While several methods have been tried—like completely painting the wood structure with thinned white glue to prevent the air from reaching the surface—we know of only one method of preventing this from happening: don't leave your airplane in the sun! Seriously, get a cover or a tent or find some shade. Also, choosing light colors will prevent the intense heat buildup. Last summer during our hottest days, I measured the covering temperature on a dark blue airplane that had been sitting in the sun at 163º. If you keep them from getting hot, there is no problem, but, for those times when they do, practice the re-shrinking techniques mentioned above, and it will only take a few minutes to bring back that pristine finish.

by John Adams

RE: Monokote/Ultracote secrets
 

Hi there, I'm pretty new to modeling. I know how to fly but I want to start building also. I've been reading about monokote, but what is oracover exactly? Is there any pictures so I get a good idea of it?

RE: Monokote/Ultracote secrets
 

http://search.yahoo.com/search?p=ora...p=mss&ei=UTF-8

Oracover is a heat shrink film covering, made in Germany (I think), that some people prefer over monokote. It is sold in the US as Hangar 9 Ultracoat; imported and distributed by Horizon Hobby.

I have built two kits and and covered them with Ultracoat. I have used very little Monokote so I cannot really compare them. My brother has built kits and covered them with Monokote. He has never tried Ultracoat.

You can get good, or bad, results with either brand.

RE: Monokote/Ultracote secrets
 

Thanks a lot for the info buddy

RE: Monokote/Ultracote secrets
 

I think the most important part is what Beepee said in post # 2 ! But there a wealth of info in this thread!!!!

RE: Monokote/Ultracote secrets
 

Gringo's tips are ALL worth noting. (BTW, Oracover is known in the States as Ultracote)

Here are a few that I will add:

1) make sure your surface is dust-free before covering. Once I've finished sanding, I will hold the wing (Or whatever) with one hand while smacking it with the other and at the same time, blowing on it (OK, so I don't have an air compressor). These structures are pretty strong and can take some slapping around, but be reasonable and don't hit it so hard that you'll break something. If you DO knock something loose, it probably needed more glue anyway :D

Once I have blown all of the dust off, I spray a rag with spray adhesive and wipe everything down. You will be AMAZED at how much dust is still on the wing. Your covering will stick nicely to that dust, but the dust isn't stuck to the wing, so the more you can get off, the better the covering will stay stuck!

2) Do NOT pull the covering TIGHT. Pull it TAUT, That is, no wrinkles. It will shrink to become TIGHT, that is what it is designed to do.

3) If you use pin striping, or any designs that have a small, sharp edge (Like the ends of a Nike Swoosh, or a star), once the trim piece is ironed on, put some thin CA on the end of a pin and carefilly place it around those small ends. It will keep them from lifting.