Tuesday, March 29, 2016
Estes Goblin - Finished!
The Goblin is a classic Estes kit. I believe they used to send it as a free gift when people ordered a certain amount of stuff. The Goblin had been out of production for years, and was brought back as a clone by Semroc.
Due probably to the popularity of the Goblin, Estes re-released their kit, so now you have a choice. Both rockets look pretty much the same, and are the same size. The main difference is the nose cone - the Semroc version uses balsa wood, while the current Estes kit features a plastic nose.
The Goblin flies on 24mm D motors. It's a very simple rocket, but this build gave me a lot of trouble! I made so many mistakes, starting with gluing the fins on. I accidentally tore the very first fin off while the glue was nearly, but not quite, dry. I had to cut it off and sand the root of the fin, but there was some tearing of the body tube.
Well, I didn't want to accept this flaw, and needed a way of covering it up. So I elected to do the fin fillets with epoxy, filled with microballoons - microscopic spheres of glass.
This makes epoxy thicker and easier to sand if you need to. It also allowed me to get some nicely smooth, curved fillets.
Epoxy fillets make the rocket heavier, and it's probably overkill for most small rockets. But it makes a larger footprint, which successfully covered the torn paper airframe.
When sanding the primer, I sanded through and actually cut into the paper body tube, raising fibers. This would have created some hairy spots on the final paint job. So I soaked the spots with thin CA - cyanoacrylate or Super Glue - and sanded the fibers off. After re-priming, the surface looked fine.
Then I had issues with the paint! I often use Rust-Oleum 2X enamel paint, which I did here. It's a pretty good paint, but some cans of it turn out not so great. I got a really rough texture, with part of the rocket looking like sandpaper, and part of it looking like dried out earth - dark cracks all over the fins. I didn't take a picture of that, unfortunately.
I used wet/dry sandpaper to sand the rough paint off. This took a long time.
I got a new can of Rust-Oleum Marigold paint - one of my favorite shades of yellow from Rusto.
The new paint went on fine, and apart from a little flaw around the edges of the black on one fin, I'm satisfied with it.
Despite all the trouble it gave me, the Goblin turned out quite nice. I did have to leave off one waterslide decal - the Estes logo, which is supposed to go just below the black band around the rocket. Unfortunately, I cut part of the decal off when I was trimming it from the decal sheet.
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