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- Jan 4, 2015
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Hi folks. I'm working on improving my fin finishing techniques. I go for a 15ft finish (looks good/OK from 15 feet away), not perfection. My most recent endeavor was with Duplicolor gray primer/surfacer, brushed on, to be sanded smooth after drying. Rocket is an Estes Executioner, with stock 1/8" plywood fins. I chose to (try and) get a primed/sanded/smooth surface on each fin prior to mounting it on the body tube. After fin attachment, I'll use rattlecan primer and then finish paint on the assembled fin/airframe unit.
As a kid, I used sanding sealer and then sanded fins by hand, not using a sanding block. I usually went for three coats, sanded after each coat. On my Executioner, I tried sanding the flat fin sides with sanding blocks: an Apogee Sanding Tee and a 3M rubber sanding block I had on hand. My thought was that I'd be more likely to get a smooth, flat surface with the assistance of a flat tool than I would if I just held the sandpaper in my hand/fingers. I used 3M, 320 grit Pro Grade Precision sandpaper (comes in a puple-ish package). I tried using both linear and circular sanding motions as I worked. I sanded each bare fin side lightly, then brushed on the primer, let it dry, and then sanded again using the sandpaper and block(s).
While these came out OK, I found that I accidentally rounded the surface down at the leading and trailing edges of the fin. I attribute this to letting the sanding tool run too far over each edge of the fin, thereby levering the block down over the edge. I was applying pressure on the tool after it ran past the fin, though I did not do this on purpose. I was careful to not apply too much pressure, and let the sandpaper do the work. Pics of one representative fin are below. Root edge is taped off with masking tape to keep the primer off of surfaces that will be glued later. You can see where I unintentionally sanded all the primer off of the leading and trailing edges.
So my question to the experienced: When sanding the flat areas of fins, do you use a tool or just your bare hands? Any suggestions/advice will be appreciated.
Pics:
As a kid, I used sanding sealer and then sanded fins by hand, not using a sanding block. I usually went for three coats, sanded after each coat. On my Executioner, I tried sanding the flat fin sides with sanding blocks: an Apogee Sanding Tee and a 3M rubber sanding block I had on hand. My thought was that I'd be more likely to get a smooth, flat surface with the assistance of a flat tool than I would if I just held the sandpaper in my hand/fingers. I used 3M, 320 grit Pro Grade Precision sandpaper (comes in a puple-ish package). I tried using both linear and circular sanding motions as I worked. I sanded each bare fin side lightly, then brushed on the primer, let it dry, and then sanded again using the sandpaper and block(s).
While these came out OK, I found that I accidentally rounded the surface down at the leading and trailing edges of the fin. I attribute this to letting the sanding tool run too far over each edge of the fin, thereby levering the block down over the edge. I was applying pressure on the tool after it ran past the fin, though I did not do this on purpose. I was careful to not apply too much pressure, and let the sandpaper do the work. Pics of one representative fin are below. Root edge is taped off with masking tape to keep the primer off of surfaces that will be glued later. You can see where I unintentionally sanded all the primer off of the leading and trailing edges.
So my question to the experienced: When sanding the flat areas of fins, do you use a tool or just your bare hands? Any suggestions/advice will be appreciated.
Pics: