Canopy sanding the fairing.

I have just finished the canopy fairing of my RV 7 doing the epoxy fiberglass fairing on the front.

I seem to have a bit of sanding to do and wondered some things:

1/ Has anyone used powered sanders like my Black and Decker mouse sander?

2/ Did you start off with 80 grit and go up to 220?

3/ Is it necessary to form a block of 4" radius to achieve the final form or could you freehand it with the powered hand sanders.

Oh and yes i have searched the forum, i am looking for recent information, thanks for any sent.

Man is that epoxy hard stuff!

dave4754 said:

I have just finished the canopy fairing of my RV 7 doing the epoxy fiberglass fairing on the front.

I seem to have a bit of sanding to do and wondered some things:

1/ Has anyone used powered sanders like my Black and Decker mouse sander?

2/ Did you start off with 80 grit and go up to 220?

3/ Is it necessary to form a block of 4" radius to achieve the final form or could you freehand it with the powered hand sanders.

Oh and yes i have searched the forum, i am looking for recent information, thanks for any sent.

Man is that epoxy hard stuff!

Click to expand...

Is this your first layup of the fairing? Then yes 80 grit to rip off all the roughness to begin your contour shape. I did not use power sanders. No real need for them and you'll go right through the material before you know it.You'll have more filling, sanding, filling, sanding, filling sanding to do before it's done. Each session for me was a finer grit paper until I was down to 320-400 for a smooth finish. I (and others) used the round side of the rubber sanding blocks from the auto parts stores for shape. Not hard just takes time.

I used a KB Kustom Shop sanding block, the top rounded part, among other rounded and flat sanding blocks, all by hand, cross stroke, started with 40 grit, and only used it for a few min and got a new sheet. it may look and feel good, but it will not cut and sand the same as a new piece, really, what is 50-100.00 of sand paper in the scheme of things I sanded on mine for one month, off the plane. slept and ate every now and then.........so glad that is over.

No power sanding for this. I used a round 1" stiff rubber sanding block, but PVC pipe will do just fine. You are forming the contour, not with the block shape, but through your approach to sanding it. I also use the palm of my hand as a backer when feathering out the edges once they are close. Contour sanding is something of an art that you need to teach yourself. The good news is that if you screw it up, you just add another coat and do it again.

You want to shape with more aggressive grits (I used 80) and finish it with finer grits. The thing to be carefull as a newbie is oversanding the aluminum in your feathering. With filler, you can keep re-filling and re-sanding until you get it right. However, you can't keep hitting the base material with 80 grit over and over. Therefore, keep your contour sanding to the filler only untill you are close to your final state, then address your feathering.

do some research on this. A key learning is that all sanding is done with strokes that are 45* to the contour line. Generally equal strokes in each 45. That is the cross-stroke that Bret mentioned above. While you do occasional stroke with the contour line, block sanding is predominantly at 45* strokes.

Good luck,

Larry