I am in the (long) process of covering my build. I am using a two color scheme and I'm having problems withthe material puckering at the point where the two colors meet.

The covering is SIG Aerokote lite (Corsair Blue) and AirBorne Models Lightex (Cub Yellow). Iam told that both materials are identical.The reason I have one of each is because SIG stopped offering the Cub yellow after I already had the Blue.

I am new at covering but I have managed to getthehorizontal stabilizer covered (and recovered) with no puckering. Today I was working onthe rudder and encountered this problem.

Myprocess is to cut the two pieces, overlap them by about 3/8" and thenbond them together using heat (obviously) onapiece of glass beforeattaching them to the framework.

However, after attaching them to the framework, I tried low heat, hight heat and even put a hole in the covering to let the expanding air escape but it just will notsmooth out. Both sides are puckered. However, theyare not stuck together due to excessive pressure.

My thought is that I may not have used enough heat to initialllybond the two pieces together and now they arepulling apart as I heat them.

Has anyone else experienced this? If so, is there a solution or technique to use?

Thanks

My solution is only buy ARF's

Flyfast,
Are trying to join two pieces of covering there, or is it layer of yellow with the blue over the top of it?? It looks like two pieces joined where they meet. If this is true then you need to assemble your pieces prior to putting them on the plane. Get a piece of glass or a mirror. Align your pieces together and overlap the edges by approximately 1/4" and use a trim iron (or the tip of your covering iron) to heat the area where the two pieces meet to attach them to each other. Now peel the assembled piece off of the glass and place it on your part to be covered and apply the covering as you normally would. This should stop the pieces from puckering like they are in the picture. Also, it will allow you to get the covering tighter as the assembled pieces will not act as one piece.</p>

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Ken</p>

Ken,

Thanks for your time. I did overlap the two colors on a piece of glass just asyou described. Ithen applied what I thought would be enough heat to join them but not so much as to shrink them. Once Ithought the two were then one, Ilifted them off as one piece and applied them to the framework.

I may just have to experiment with a bit moreheat to join them. Like Isaid, it worked before on the horizontalstabilizerbut I just didn't write anything down about the exact iron setting Iused. I'mhoping to avoidwasting any more material by soliciting the experience of others.

It will be a couple of weeks before I can work on the project again. However,when/if I find a solution, I'll post it.

Thanks again for your time. I'm open to any otherthoughts or advise. (other than buying ARF)

Greg

The other method I have used rather than buy a ARF is bartered with a friend that does really nice work.

It sounds to me what your doing is what he does. I'll see him at the field tomorrow and will ask him and another club member that does really good covering if they have any ideas for you.
 

My covering method is the same for any surface, any covering. it's a combination of a skill learned from a recognized expert in the subject, and some instructions used for a completely different process:

1) Grab a covering iron, a heat gun, and an old sock. Not a covering sock, a sock sock...the kind you wear on your feet. Ball the sock up to about the size of a tennis ball.

2) Lay the covering into/onto/around/over the part. You're not looking for a smooth, exact fit...but try to get it to lay down "good enough"...basically, move it around so it sits as flat as you can get it, but don't stress over trying to get it to lay perfect.

3) Tack the covering down along the edges with the iron. On, say, a flat stab, this is pretty easy to figure out. In a over a complex curve, it's a bit harder. Basically, what you're looking to do is to prevent any shrinking that pulls covering edges up and away from the surface. So, find the "farthest" points from the center of contact, and tack those...then tack a few bits in between those.

Note...you're not trying to seal up the entire perimeter...you're just tacking enough so that as the covering shrinks, it has something to "pull against". Remember, by definition, covering will attempt to pull FROM THE CENTER OF THE PIECE equally in all directions...Imagine how a circle might shrink to a dot, and you'll have the mental image.

4) Begin heating, slowly, with the heat gun. Use the gun to pull the covering tight, and shrink out any wrinkles or deformations. As the covering shrinks down and contacts the surface, push it down...HARD (as hard as you dare, given whatever surface you're working with)...with the sock, working the sock behind the path of the gun. Ideally, you'll work from a "corner" of the surface, fanning out in broader and broader "sweeps" as you go.

==================

It takes a bit of practice, but once you get the hang of it, you'll turn out glass-smooth covering jobs over even the most complicated of curves, AND the sealing with the sock will force the adhesive into the wood, meaning the covering job will NEVER bubble or wrinkle, no matter what conditions you put it in.

I believe the key word here is practice and I do appreciate the input.  I'm going to build up some small structures and use scrap material to figure it out.  I did seal it up all the way around the outside before shrinking it.  Maybe that was part of the problem.  So, I need to try it your way.</p>

Do you still press and work with the sock when covering a somewhat thin framework structure such as this rudder?  My concern with was pressing to hard in the middle and having the adhesive side of the covering sticking to one another.</p>

I just went to the workbench and tried the heat gun.  I had been using the iron only.  Unfortunately it didn't work.  I believe this material has shrunk all that it is capable of.  It's to the point of removing it and trying again.</p>

Thanks,</p>

Greg</p>

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Hi flyfast,

To add to the excellent advice to date I have found that if you join the two pieces as described it only works for me if the join is in a straight line over open frame work, Im probably doing it incorrectly. If the line is curved I have only had success if there is sheeting under the join. My two cents worth, and that is probably more than it is worth is to add some thin sheeting under the line of the join.

Good Luck,

Colin

Try heating the areas forward and aft of the pucker. You may be able to shring the sides which will pull the wrinkle out

Hey, Flyfast, </p>

Are you going basically blue, with the yellow secondary? If you are going Yellow, with a Blue secondary (and not much of the secondary) I would cover the whole thing with the Yellow, and paint the blue. I have acheived my best striping and curves with paint, never reall good with over-lapping films. If the over-lapping is what you have your heart set on, use your glass pallette, and an actual adhesive to bond the two colors. Since you are fighting "shear" when shrinking the films, the two colors will always act independantly of each other. BOND them with an adhesive thatis heat resistant, let cure, and then apply as a single film. Good luck.</p>

Great ideas from everyone.  Thanks for your time.</p>

 I am overlaping the two colors by a minimum amount to save weight on this model.  However, after reading the different ideas posted here, it occured to me that on something as small as the rudder that I can cover the entire surface with yellow and then apply the small amount of blue on top by using just enought heat to activate the adhesive but not shrink it.  That will add only an insignificant amount of weight.  I also like the idea of using a small amount of balsa backing (also an insignificant amount of weight.).  Or, perhaps both, with little adverse affect on weight.</p>

As I said, it will be at least two weeks before I can work with it again, but when it do,  I my try several different techniques on scraps just to see what works best.  </p>

I first wrote the question so that I could save time and material, but now all the ideas have me wondering which might work best.  </p>

I'll post later and let everyone know which technique I used and how it worked out.</p>

Thanks again.</p>

Greg</p>

What type of Paint can be used to paint Monocote. I can't get the same color in the Topflite lustracote so I need to use a differant paint and not sure what is best to use.

I found that the World Models material is not the same. I have tried Mono, Ultra, Coverrite and nothing works with the World. Bubbles and crinkles just as you show. <div></div><div>JimO</div>

The World Models are covered with a product they call Toughlon. It is different from Monokote and Ultracote. I did a couple of small repairs on a World Models Super Chipmunk using Monokote.</p>

Ken</p>

I was told by a SIG representative that Lightex and Aerokote Lite is the same material.  This was at the same time I was told that SIG would no longer be carrying the Aerokote Lite.  This information was passed along to help me find a source.  Is it a perfect material match?  I don't know, but I did get this overlapping  technique to at least work on the horizontal stabilizer ( I just don't remember my technique/heat settings).  So,  I know it's possible with Lightex and Aerokote Lite.   Not sure about the Toughlon and other materials.</p>

Greg</p>

Thanks to everyone that posted a comment in an effort to help. I finally removed the covering and started again. This time I just covered the entire rudder with yellow and then cut and applied the blue over it. It turned out great with only a few bubbles to work out.

I still have the wings to work on so I'll work more on the overlap method that I used on the horizontal stabilizer rather than a complete covering of the underlying color (yellow) and fighting the bubbles.

Thanks again for all the suggestions. Here are a few pictures of the latest results.