Covering The Fuselage
Poly Fiber Method


The following is a Poly Fiber covering job of the fuselage. We will also present an AFS method 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.

In this build, the builder installed a heater box. However, although you will notice this in some of the photos, we will not be covering this installation in this build section.


Tapping Down Edges

Prior to taping, it is recommended to first use either a plastic mallet or square head "shop hammer" type to tap down any sharp aluminum edges as close to the aluminum tubing as possible. This should be done on "ALL" fuselage side ribs and sheet aluminum edges throughout the fuselage. This will help prevent the long term chances of the aluminum edges 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 between 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 similar 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, like that 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 quickly and would not be the best choice for this job.

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

         
Click to Enlarge


Adding Quilt Batting To Aluminum Sheeting & Longerons

Click to Enlarge
         

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. Adding quilt batting along the longerons will also help the fabric smooth out when shrinking and improve the final look. 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.

         
Click to Enlarge

Quilt batting was used on the tail cover/glue plates. Notice how smooth the fabric lays on the batting after ironing the fabric. If no batting was used and the fabric was glued to the aluminum sheet, the fabric would most likely have permanent wrinkles in the surface.

         
Click to Enlarge

Masking For Straight Glue Edge

When getting ready to apply your glue, it is best to use an inexpensive masking tape to create a "straight" glue edge along the surface of the tubing. This will not be needed where you will be gluing and wrapping the fabric "around" the inside of the tubing surface. This will improve the final look of all glues seams.

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

See MEK Warning Information before using.


What Glue To Use

There are two primary types of gluing systems, Poly Fiber's and AFS. This builder will be using the Poly Fiber system, using Poly Tak glue.


Suspending The Fuselage In A Hay Ring

Click to Enlarge
         

The builder used the method of covering the fuselage while suspended in a farmers hay ring. This method works very well as you can rotate the ring and fuselage to work at waist to chest level on any portion of the fuselage. The hay ring was bought at a farm supply for $125.00 (2005) and was sold after it was no longer needed and cleaned up for $100.00. This ended up costing the builder only $25.00 for its use. Not a bad deal!

If you plan to use this method, you need to fabricate 4 steel plates about 9" x 6". Then, you need to measure the width of the root tube and add a half inch to both sides, then drill a 5/8" hole in all four corners of each steel plate the width of the root tube, plus 1". Use 1/2" x 9" bolts to secure the plates around the root tube and hay ring at the front and rear of the hay ring to support ring to fuselage for rolling. A heavy gauge guide wire is needed to attach on both sides from the hay ring to the front seat down tubes. The only additional items needed are some wooden 4"x4"x5' blocks to place at the bottom of the ring to keep the fuselage and ring from rolling when you are working.

         
Click to Enlarge


Taping Off To Smooth Edges & Protect Fabric From Wear

Click to Enlarge
         

The pictures show three layers of Dacron tape applied over rivets and structure sharp edges. This should result in a very good looking finished painted fabric surface.

         
Click to Enlarge


Click to Enlarge

Click to Enlarge

Click to Enlarge


Covering The Bottom

Be sure to lightly sand off any corrosion with 400 grit sandpaper (NOT steal wool) and clean all aluminum tubing with MEK before taping off and applying any glue. Apply about a 2" glue area on the edge of the nose cone.

After taping off for any glue lines, apply two coats of Poly Tak glue with a 1" to 1-1/2" paintbrush, allowing each layer to dry between applications.

The builder forgot to take a couple photos, so you will have to use your imagination on the bottom covering.



Click to Enlarge
         

As the bottom is flat from side to side, the fabric will lay quite flat and smooth on the bottom fuselage cage and tail. However, you may want to use spring clamps to secure the fabric to the fuselage, removing them as you go, while tacking the fabric to the fuselage.

         
Click to Enlarge

You will need to reactivate the Poly Tak glue below the fabric by applying MEK with a small paintbrush in about 6" to 10" long strips. Use your fingers to rub the MEK down through the fabric to pull the Poly Tak glue up into the fabric. You should notice as the MEK dries, you will feel the Poly Tak glue in the material. Start tacking the material to the cage at the front of the fuselage from side to side and work your way to the tail.

As you work your way from the nose cone to the tail, your fabric may start going off to one side. This is normal as you may be pulling a little more on one side then the other to flatten out any wrinkles in the fabric as you tack the fabric to the fuselage cage. This should not be a problem as you should have plenty of fabric to shift at the tail of the fuselage.


Click to Enlarge

Once you have the bottom fabric fully tacked down, you can now trim off any excess material, and finish gluing the material to the aluminum tubing by reactivating the glue with MEK.


Shrinking The Bottom Fabric

Cooking Thermometer
Click to Enlarge
         

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

Since the bottom fabric is not dependent on any other area, you can go ahead and do the final shrink at 350F.

         
Raytek Minitemp MT4
Click to Enlarge


Covering Rear Wall & Firewall

Click to Enlarge
         

On this build, there are several modifications in this area. On the back cabin wall, the builder modified it to have belled or what is also known as "wide sides". Also, the builder would not be using the factory fuel tank, so the aluminum tube holding the riveted hinge for the plywood door was removed and a larger new door, using aircraft plywood, was made and riveted to the lower aluminum tube.

CAUTION: DO NOT REMOVE THIS ALUMINUM TUBE IF YOU ARE USING A FUEL TANK IN THIS AREA AS IT IS NEEDED TO RETAIN THE FUEL TANK IN CASE OF FORWARD THRUST, LIKE IN A SUDDEN STOP.

As to the engine firewall, the factory installs a "short" piece of aluminum sheeting from the top to about 6" from the bottom. As the builder was also adding a heater box, the remainder of the engine firewall was aluminum sheeted as well as the bottom area, just below the engine. All the aluminum sheeting also had quilt batting applied to the aluminum surfaces before covering.

The wiring was then brought through the aluminum sheeting via military quick disconnect sockets and rubber grommets.

So, all we can say here is you would cover these areas just like you did with the bottom covering by gluing the material around the aluminum tubing. Do this covering step, as well as, shrinking the fabric "BEFORE" covering the sides.

         
Click to Enlarge

Covering The First Side

Poly Brush is not only a pinkish color fabric coating to seal the fabric prior to painting, but it is also a "GLUE" and will be used anywhere you are joining fabric to fabric where an aluminum tube is not below the fabric. In these areas, you will not use Poly Tak glue. Only use Poly Tak glue where an aluminum tube is below the fabric.

There are two pieces of fabric per side of the fuselage. You will attach the larger of the two first, which extends from about the middle of the two place door opening to the rear of the tail. The second piece is much smaller and is attached from mid-door opening to the nose cone or over the fuselage nose, if... you are not installing a fiberglass nose cone.

For the first side, you will need to apply the glue edge masking tape to the aluminum tubing just above the fabric contact point and around the tubing. This will be for use with Poly Tak glue.

However, applying Poly Brush to the bottom fabric edge will be a little different. Apply your glue edge masking tape about 1-1/2 inches from the bottom aluminum framework onto the bottom fabric as you will be gluing the side fabric directly to the bottom fabric using Poly Brush, not Poly Tak glue.

Apply two coats of Poly Brush to the bottom fabric edge 1-1/2" area prior to covering, letting each coat dry completely between coats.

Before attaching the side fabric anywhere, you first need to measure and cut the main gear weldment hole in your fabric. Remember, the gear leg weldment is at an angle, so you need to compensate for this offset. Otherwise, you may not have enough fabric to attach to the bottom of the fuselage. After you have the fabric slipped over the weldment, smoothed out, and centered over the fuselage, tack the material at the bottom. Do this from about 6" behind the gear weldment, forward to the end of the fabric at about the mid-door opening with Poly Brush. This is to keep the fabric from moving as you glue the fabric down causing a big wrinkle near the gear weldment.

         
Click to Enlarge
Using spring clamps to hold the fabric in place, start at the top of the fuselage. Reactivate the Poly Tak glue on the tubing working down the down tubes at the firewall and rear compartment until you reach the bottom of the engine firewall area. Now, carefully smooth out the fabric as much as possible to firm and glue the fabric down to the 90 & 45 degree tubes to the rear of the engine area. This area is the most difficult section as you need to make sure you do not cause any large pulls or wrinkles in the fabric. (THIS IS IMPORTANT) Now, gently pull and smooth out the fabric and finish attaching the fabric to the rear cabin down tube.

Work along the tail's top rail aluminum tube and longeron at the same time, attaching the fabric as you go. First tack about 10 inches at a time to the top tube with glue, then to the bottom longeron with MEK to draw the glue to top surface. Attach and trim the fabric as you go to the cover/glue plates at the end of the tail. You can now attach the fabric to the cabin side rails, as well.


Click to Enlarge
         

It is now time to attach the front side fabric panel. This area is rather easy, as it is flat for the most part, unless you are covering the nose area, as well. We have not covered the nose with fabric, so we are unable to give you any pointers on this. Attach the fabric with Poly Tak to the top side rail and nose cone. Use Poly Brush for attaching the bottom and gluing the seam between the two side fabric pieces together.

         
Click to Enlarge

Apply two coats of Poly Brush on the fabric which is on the bottom of the seam, then a wet coat to lay the top seam edge onto. Then brush more Poly Brush onto the seam surface to make sure the Poly Brush is thoroughly soaked through the fabric. Allow to dry, then wet again with Poly Brush and apply a strip of bias tape over the seam, also applying Poly Brush to the tape to make sure the Poly Brush is worked through the tape to the fabric.


Click to Enlarge
         

Now you will need to use Poly Brush to apply a "wet coat" on the bottom fabric 1-1/2" glue area and lay the side fabric edge into the wet Poly Brush. At the same time, use a small 1-1/2" paintbrush to apply wet Poly Brush to the surface of the fabric and work the Poly Brush thoroughly into the fabric. Don't worry if you get Poly Brush smudges in other areas of the fabric as you will eventually be giving the fuselage three coats of Poly Brush prior to painting.

Once you have finished gluing the side fabric and the glue has fully cured, you will need to do the first shrinking of the fabric. Set your iron at 225F to take out all the loose wrinkles and bring it all slightly taut. You can do the final shrinking to 350F as this side is also independent from any other side.

         
Click to Enlarge

After ironing the side at 350F, you need to go back over all the seams, also at 350F to take out or flatten any wrinkles in any of the seams. This includes both the Poly Tak and Poly Brush seams. Once this is done, use Poly Brush to apply a 2" bias tape to the seam edge of the bottom fabric Poly Brush seam, making sure the Poly Brush is thoroughly worked through the bias tape. After the tape is fully dried, iron it down at about 250F to 275F.


Covering The Second Side

Now, repeat the steps above for covering the other side of the fuselage.


Click to Enlarge

Click to Enlarge

Click to Enlarge


It's now time to start considering how you plan on painting your covered fuselage, but that will come later in another building web page in this section of the site.