A common question in my PM inbox is how to extend the edge of a cowl that has been trimmed a little too short. The subject has been covered very well in the past, but perhaps a dedicated thread will search better.
There are two methods. A small extension (like 1/8", maybe 3/16") can be done with a flox/epoxy mix. A longer extension is done with multiple plies of glass fabric.
Both methods are based on a scarf joint. Block sand the scarf with coarse grit paper. The scarf should be 3x wider than the glass thickness, minimum. The wider it gets (5x, 10x thickness) the stronger the joint becomes.
The backing plate can be aluminum, smooth stiff cardboard, almost anything handy. Cover the face of it with some slick tape so it will release from the epoxy. I would simply cleco it into place and fill the holes later.
Extension with fabric is straightforward. Lay enough plies to equal the thickness of the original glass, let it cure, then sand the outside flush and trim the edge to the new length.
Flox is milled cotton fiber. In a flox/epoxy mix the fiber provides isotropic tensile reinforcement. Cured flox is quite tough, which is why, with an appropriate scarf, you can use it alone for a short extension. Same procedure as above.
No need to suffer the pain and embarrassment of ugly cowling gaps. You can scarf and add flox or fabric one evening, then shape the edge the next evening. Have fun!
There are two methods. A small extension (like 1/8", maybe 3/16") can be done with a flox/epoxy mix. A longer extension is done with multiple plies of glass fabric.
Both methods are based on a scarf joint. Block sand the scarf with coarse grit paper. The scarf should be 3x wider than the glass thickness, minimum. The wider it gets (5x, 10x thickness) the stronger the joint becomes.
The backing plate can be aluminum, smooth stiff cardboard, almost anything handy. Cover the face of it with some slick tape so it will release from the epoxy. I would simply cleco it into place and fill the holes later.
Extension with fabric is straightforward. Lay enough plies to equal the thickness of the original glass, let it cure, then sand the outside flush and trim the edge to the new length.
Flox is milled cotton fiber. In a flox/epoxy mix the fiber provides isotropic tensile reinforcement. Cured flox is quite tough, which is why, with an appropriate scarf, you can use it alone for a short extension. Same procedure as above.
No need to suffer the pain and embarrassment of ugly cowling gaps. You can scarf and add flox or fabric one evening, then shape the edge the next evening. Have fun!
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