At group launches, sometimes you'll see flying models with the burnt laser cut edges under the paint.
The tabs haven't even been sanded off. If the tabs are left on, the root edge gluing surface won't be as strong. The attachment tabs will slightly raise the root edge off the body tube.
You don't have to remove every last trace of the laser burn and hold-down tab. If you sand too far, you've changed the shape of the fins. Just sand enough until the darker brown color is almost gone.The instructions still say to stack and sand the four fins. I can understand this back when fins were die-cut using razor blades set in a block. The blades could shift when punching out fin sets by the hundreds.
But now, fins are drawn on a computer screen. Draw one fin, copy it and paste. There shouldn't be any difference between the first, fourth or thousandth laser cut fin.
But for whatever reason, some kits with "identical" laser cut pieces have have had slight differences in size. Always check them by stacking to see if they match up.
I have trouble, when sanding stacked fins, with sanding them into a curve. Even using a sanding block; even when sanding in one direction only. Must be a personal problem... so anyway, I always sand the nubs down and call that good. You'll never see the burnt edges through my paint.
ReplyDeleteHi Chris,
DeleteIf the fins are laser cut all should be consistent in size.
You don't really have to "even" up laser cut fins by stacking and sanding. Sometimes I sand them one at a time.
I sand just enough to remove the blackened edges. Too much and you could change the shape of the fins.
One thing I’ve found useful for sanding flat edges is to glue a full sheet of sandpaper to a high-quality piece of 3/4” multi-ply Baltic Birch plywood. You can take individual, or stacked fins, and drag them across this sanding base, and get a really nice, square, flat edge.
ReplyDeleteHi Lee,
DeleteI've got sanding blocks! The best one is the Great Planes Easy Sander with the self adhesive sandpaper rolls.