vasek

My Feedback: (4)

I have trouble sanding shapes that recquire more than the use of a sanding bar and some electrical tape, such as the LE of an eliptical wing (Spitfire) and the end tips of the wing ect. HOW do you sand these without deforming the shape? Keep in mind that the LE of a Spit has an eliptical shape AND starts thicker at the fuse and gets very thin at the tip.

I'am sure there are some good methods to be used, I just can't think of any...

THNX for helping out!

Edwin

My Feedback: (2)

The only special tool I use is a "T bar" sanding bar with aluminum oxide 80 grit sand paper stuck to it. That sand paper is the best thing I've ever used when it comes to the rough in sanding. Takes a lot off pretty fast. Basically, I free hand all my leading edges and V grooves on elevators and rudders. A center line and edge lines is all I use for a guide. I bought that GP shaped sanding bar for doing V grooves and rounded leading edges but found it to be more trouble than it was worth. I dont use it any more.
Edwin

MMallory

My Feedback: (1)

vasek,

Practice, practice, practice. It may help to hold the wing on the edge of a table to make your sanding more accurate. I usually start by putting masking tape on the sheeting where I don't want the sanding bar to cut. Next I use a razor plane to get the rough shape, then I switch to a rough grit moving progressively down to a fine grit paper on a very long T-bar. Sand a little, eyeball, sand a little more. Use a soft paint brush, vacuum or compressed air to get the balsa dust off often.

Happy sanding,

Mark

astropuppy

My Feedback: (23)

use a razor plane to get the rough shape. Then use a strip of sand paper perpendicular across the le as if you where buffing a shoe. No T-bar, LE's are round not flat sided.

greg-RCU

...and patience, patience, patience. Long slow strokes not fast furious vibrations.

For that Spit' LE I would lay it flat on the bench, flip it over every couple of strokes, and get real careful near the finish. I would also look for a semi stiff piece of plastic or cupped material to back the sandpaper. Something with a changing radius so I could start with the small radius near the root and draw out to the flatter section near the tip.

Plus there is always filler?

CurtD

My Feedback: (1)

The real secret I think to getting good shapes like leading edges, compound curves on fuselages, etc. (other than lots of practice to build up your skills) is first learn to properly use a razor plane. Figure this little jewel out and it will drastically reduce your sanding load. Next, learn to sand so that you are not sanding directly across or with the shape your trying to create such as a leading edge. Get it to general shape by sanding diagonally, going both directions, using a good, flat sanding board that the sandpaper is attached to. You simply cannot get proper shapes without the board. Start with 80 or 100 grit (I prefer garnet but alum. oxide works too) to get your piece close (after using the razor plane to remove most of the unnecessary wood) then work with finer and finer grits. I usually go to 220 after the first sanding, then 320 to finish, depending how the wood is going to be covered (iron-on or paint).

Take your time and practice, practice, practice. When you think you've sanded enough sand some more.

vasek

My Feedback: (4)

Curt, the diagonal sanding technique works FINE!
THNX for the tip