Covering The Wings
AFS System



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The following is an AFS, CecoBond Cement covering job of the wings. We will also present a Poly Fiber system wing covering job in another web page. Please remember, there are usually several ways to complete any job, the following information is just one of these examples.

We have added photos from another build showing a couple of missing areas in the beginning of this stage of covering. However, the covering process photos will be exclusively from our builder using the AFS gluing system.

NOTE: Aircraft Finishing Systems (AFS) is no longer in business. However, the production rights to the former AFS of Montana has been assumed by Stewart Systems of Washington.


Tapping Down Edges

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Prior to taping the gusset edges, it is recommended to first use either a plastic mallet or square head "shop hammer" type to tap down the edges as close to the aluminum tubing as possible. This should be done on "ALL" gussets and sheet aluminum edges throughout the plane. This will help in the long term effect of reducing the gusset edges from cutting or wearing through the covering or skin of the plane after the plane is flying.

Taping The Edges

The best tape to use for taping off the gusset edge and rivets is a Dacron First Aid tape available at WalMart in 1" X 10 yard rolls. The covering is also made of Dacron, so if it ever gets wet, it will not mildew or decompose. For all the edge and rivet taping throughout the plane, you will need to buy about 5 to 20 rolls, depending on how many layers of tape you use. Only one layer is needed to protect the fabric from sharp edges. However, for a more professional look in hiding edges and rivet heads under the fabric, you may wish to use up to three layers.

Aircraft Spruce also sells a simular tape. A roll of 1" X 60 yards sells for $7.30 and may actually be the better deal, price wise.
(Pricing as of 10/2006)

Some builders have successfully used sports grip tape, such as used as a grip aid on bat and hockey stick handles, while some others have used just plain masking tape for the taping of edges. However, masking tape wears very quickely and would not be the choice for this job.

Any of the above mentioned tapes seem to do the job of stopping the fabric from abrading on the rivets and sharp edges and eventually wearing through the fabric.

         
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Be sure to apply three (3) layers of the Dacron tape over all rivets and sharp edges, like the gussets and aluminum sheeting edges.

         
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Adding Quilt Batting To Aluminum Sheeting

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Although not required, adding a quilt batting to all aluminum sheeting surfaces will keep the fabric from unevenly sticking permanently to the aluminum when painting. This also gives a much smoother surface and look to the fabric after painting. A standard quilt batting and double sided Scotch Tape was used for this purpose. Both products are available at WalMart and many other stores.

         
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First, lay out the quilt batting, then cut the size needed to completely cover the surface of the aluminum sheeting. Apply the double sided Scotch Tape on the aluminum sheeting along its inside perimeter, then diagonal strips about 4 inches apart down the length of the sheeting.

Now, just lay the cut batting onto the aluminum sheeting and press down to adhere the batting to the double sided tape. That's it!

         
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Masking For Straight Glue Edge

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When getting ready to apply your glue to the spars and wing tips, it is best to use an inexpensive masking tape to create a "straight" glue edge. The glue edge about 1/8" after where the covering fabric starts to wrap around the wing spar. You will need to cover the "BOTTOM" of the wing first.

Before applying the glue edge tape, be sure to completely clean all aluminum parts to be glued with MEK.

See MEK Warning Information before using.


What Glue To Use

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There are two primary types of gluing systems, Poly Fiber's and AFS.

Our builder will be using the AFS bonding system, using CecoBond Cement and an AFS Heavy Duty Cleaner.

         
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Covering The Bottom

After the masking tape has been applied, you will need to apply only a single coat of CecoBond glue from the glue line and extend around the spar to about the middle of the inside of the spar. Use a small paint brush to apply your glue.


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You can either tape the fabric into place or use something to weight the fabric along the edge to hold the fabric flat and without major wrinkles for gluing.

         
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The CecoBond glue used with the AFS bonding system should be applied with the temps between 65 and 95 degrees Farenheit. Let the cement tack up for about 5 minutes then apply the fabric to that cemented area. Brush glue down thru the fabric to that cemented area and wipe away any excess glue with a damp paper towel while, at the same time, smoothing the fabric down. Don't use a wet towel as that will wick the glue from the fabric.

         
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The cemented area should show an even color indicating a complete bond between the fabric and the metal. Drying time can be up to four hours depending on the temperature and the humidity.

Now, repeat this process for securing the fabric to the wing tips by 2" and the inboard covering if you plan to cover the inboard end. (See next photo).

         
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You will now need to turn the wing over, top up, and trim off any access fabric from the edge of your glue area before finishing the edge gluing process.

         
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After you have covered the bottom, you will need to open any bolt or rivet holes in the fabric on the spars which are under the applied fabric. If you do not do this before covering the top of the wing, the holes will be very difficult to locate under two layers of fabric.

Using an inexpensive pencil soldering iron, burn or melt the fabric to open the holes "now" before continuing.



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After you have trimmed off the excess fabric, finish gluing down the remaining fabric along the edge to the spar with CecoBond glue.

Apply additional glue to spar if needed to fully tack down the fabrics edge.

         
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Shrinking The Fabric

Cooking Thermometer
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Start with a household iron set at about 225F to 250F or 107C to 121C. Most builders will use either a $10.00 cooking thermometer or the far more accurate $70.00 Raytek Minitemp MT4 laser, infrared thermometer, available at www.infrared-usa.com.
Pricing as of October 2006

         
Raytek Minitemp MT4
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After allowing your glued material to set and harden for a while, you will need to shrink the bottom wing fabric before proceeding.

Using a household iron and either a candy thermometer or laser temperature gun, adjust your iron to about 250F degrees and shrink the material slowly until it is taut. You will not do the final 350F degree shrinking until both top and bottom fabric gluing have been completed.



Covering The Top

When applying the glue edge masking tape, start at about 1/8" after where the covering fabric starts to wrap around the wing spar at the top and end about 1/8" prior to there the bottom fabric leaves the spar. This will give you about a 2" glue surface to work with for gluing the top fabric to the spars. Wait until the first coat of glue has fully set up before applying the second coat.

Prior to applying your glue to the spars, first apply about a 1/4 inch coat of CecoBond glue to the top portion of the ribs from one end to the other. You will need to reactivate this glue "after" ironing the fabric to full tightness and before applying the reinforcing tape on the fabric above the ribs. This will take place in the next article, called "Securing & Riveting The Wing Ribs".

Use a small paint brush to apply your glue. Again, you will need to apply a single coat of the glue between the two masking tape glue lines. Let the cement tack up for about 5 minutes then apply the fabric to that cemented area. Now, remove the masking tape by folding the tape back onto itself and slowly pull the tape off.


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The top fabric is attached much like the bottom, except in the area of glue applied to the spars. (See Next)

         
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Once you have finished gluing the top fabric and the glue has fully cured, it is time to start shrinking the fabric.

First, set your iron at 250F degrees to take out all the loose wrinkles and bring it all slightly taut. This lower temperature will keep you from shrinking one end of the wing fabric more then the other. Once this has been done, reset your iron to 350F degrees and iron again to bring the fabric to full tightness.

         
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Now, turn the wing over and iron the bottom at 350F degrees and you are done with the wing covering process.



In the next section, we will go over attaching the top fabric to the wing ribs with reinforcing tape, rivets and finish tape.