Covering The Wings
Poly Fiber System
The following is a Poly Fiber, Poly Tak covering job of the wings. We will also present an AFS 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. |
Be sure to apply three (3) layers of the Dacron tape over all rivets and sharp edges, like the gussets and aluminum sheeting edges. |
Before applying any tape or glue, be sure to lightly sand off any corrosion and completely clean all aluminum surfaces to be taped or glued with MEK. (DO NOT USE STEEL WOOL) See MEK Warning Information before using. |
Another Tip! Concerning "old" Poly Fiber - Poly-Tak glue. It is said to throw it out if it becomes dark in color. Depending on how the glue is stored, this can happen after a year or two of sitting in the can. When the glue begins to darken with age in the can, it loses some of it's ability to create a strong bond between the metal and the fabric. I know some guys take a long time to complete their build. You should be informed about using old dark glue if you wait too long to finish with the fabric covering. |
Use a small paint brush to apply your glue. Wait until the first coat of glue has fully set up before applying the second coat. Once both glue coats have completely dried, remove the masking tape by folding the tape back onto itself and slowly pull the tape off. |
There are two primary types of gluing systems, Poly Fiber's Poly-Tak with MEK and AFS bonding system, using CecoBond Cement with AFS Heavy Duty Cleaner. We will be using the Poly Fiber system for this process. |
Making sure the fabric is as free of wrinkles as possible, liberally apply about 10 inches by 1 to 1-1/2 inch of MEK with a small brush to the surface of the fabric which will soften the glue below. Using your fingers, immediately work the glue on the spar into the fabric until the MEK has evaporated. For safety reasons, it is recommended to use MEK resistant chemical gloves. |
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 Poly Tak 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 with MEK 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". The builder of this Challenger used a personal technique. What was done was to apply two coats of Poly Brush to the glue area, then two coats of Poly Tak on top of the Poly Brush coats. This is the reason for the "pinkish" coloring in the glue. Although this works, Poly Fiber only gives directions for the use of just the Poly Tak. |
Use a small paint brush to apply your glue. Wait until the first coat of glue has fully set up before applying the second coat. Once both glue coats have completely dried, remove the masking tape by folding the tape back onto itself and slowly pull the tape off. |
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. |
That's it, you finished one wing. Repeate the above processes for the remaining wing. |