TIP: Instead of using masking tape, you can use a strip of clear packing tape. You can sand through masking tape, you won’t sand through the edge of the thicker clear packing tape.
Before sticking the tape down on the taper line, diminish the stickiness of the tape by pressing the tacky side down on your pant leg a few times. If you used the tape right off the roll, it could pull up and remove some balsa.
You’ll be able to check the thickness and straightness of the taper if you LIGHTLY mark the leading edge with a quick swipe of a permanent marker.Don’t make this too black, you don’t want it soaking into the balsa. If the leading edge is left with a dark ink line after sanding, paint coats may not cover it up!
Sometimes an older marker (that is starting to dry up) works better.
The idea is to lightly blacken the leading edge so you can easier see how much is being sanded down. With the edge blackened you can see how straight the "knife edge" line is.
400 grit sandpaper on a block was used to sand the taper.
Sight down the (soon to be) leading edge to check the thickness of the taper for consistency. You could take it down to a knife edge, but I like to leave it with a little squareness at the top for strength.
I really like the tape idea. I will give it a try for sanding simulated super-sonic airfoils into a scale model I am building.
ReplyDeleteThe tape idea is one way to go. It's an old technique I first saw in the 1970s.
ReplyDeleteDepending on how rough your sandpaper is, you could start to sand into the tape. If you used masking tape you can sand right into it.