Fin edge finishing

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Joshua F Thomas

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How do you get a good airfoil shape? I can sand simple curves on edges easily enough, but my attempts to sand an airfoil into balsa was frustrating.

Follow up question: How to sand down a set of fins so they all match? You can sand the edges down flat easily enough as a group, but trying to put a curved edge on three fins at once doesn't seem to work, or am I doing something wrong?
 

o1d_dude

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How do you get a good airfoil shape? I can sand simple curves on edges easily enough, but my attempts to sand an airfoil into balsa was frustrating.

Follow up question: How to sand down a set of fins so they all match? You can sand the edges down flat easily enough as a group, but trying to put a curved edge on three fins at once doesn't seem to work, or am I doing something wrong?
Visit North Coast Rocketry and look at their “Airfoil Assistants”. They look rather weird until you actually try using them.

Highly recommended.

It you want to do it the old fashioned way, place the trailing edge of the fin even with the edge of your work surface and hold your SANDING BLOCK at a slight angle and sand lightly along the edge until you get the edge you want. The most important thing in this process is the SANDING BLOCK. You can also sand across the edge but you run the risk of splitting the edge depending on the grain orientation. Balsa is very soft even though it’s classified as a “hardwood”.
 

Joshua F Thomas

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Visit North Coast Rocketry and look at their “Airfoil Assistants”. They look rather weird until you actually try using them.

Highly recommended.
Ok, those look pretty interesting. Do you just put in the sandpaper, insert the fin and sand until you have the desired shape?
 

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