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Sunday, September 19, 2010

Semroc Little Joe II Build Part 3 Fins


Sorry, I wasn't able to get online yesterday to do blog entries.
Once again, AT&T Internet was down. Last month it was down for a day.
Two strikes for AT&T, one more and they are OUT!

Back to the Little Joe:

The yellow clay will roll up and go into the BT-3 escape tower tube above the tower.
Above that is the fin pieces still on the balsa sheet.


The sheet was sanded using a block and 400 grit sandpaper.

I've grouped the pieces together, there are five balsa pieces sandwiched inside the fin cover overlay.



I did take some extra time to sand the sides of the fins square and remove some of the black from the laser cutting.

TIP: Next time you open a kit with laser cut fins, take a good look at both sides of the balsa before removing the fins from the sheet. You'll see that the laser line is thicker and more black on on the top side than on the back side. (This is easiest to see on thicker balsa sheet.) The darker side was the "face up" side of the balsa when it was cut.

A laser will cut the face up side a little wider (picture a wedge of light stuck in the surface) than the side that is down and away from the light.
I usually sand the edges square to remove a bit of the higher edge (the down side during the burn) from the laser cutting. This guarantees the root edge will stick straight out from the body tube when gluing on the fins.

On a model like the Little Joe, you'll want the fin pieces gluing straight up from the fin cover card stock.

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