Tuesday, May 24, 2016

Centuri X-24 Bug Build, Part 2, Parts Prep

The body skins were printed on 110 lb. stock. I didn't have the original model anymore but I think the parts were printed on heavier stock. I had to beef them up.
Inkjet printed cardstock will have to be sealed. A landing on dewey grass will smear the ink.
I first sprayed the sheets with Krylon clear acrylic, three coats.
I went over that with Future clear applied with a brush.
This glossed up the paper stock and helped harden up the paper.

The former bulkhead template was traced onto 110 lb. cardstock and glued onto some corrugated cardboard with a glue stick.

Anytime I've built a kit with a pressed in bulkhead former, the edges of the former press hard against the interior walls. This sometimes left a raised ridge on the outside of the shroud.
Corrugated cardboard would have a softer edge with less chance of deforming the large cone shroud. Worth a try, right?

The original kit used a ST-7 tube, thicker walled and slightly wider than an Estes BT-20.
I traced around the ST-7 tube on the center of the bulkhead.
(If you are using a BT-20, trace around that.)
The top hole of the formed shroud is printed to fit the Centuri ST-7 engine mount tube. If you are new to the hobby, the ST-7 is thicker walled and a slightly larger diameter than the Estes BT-20.
If you use the BT-20, you can do a few wraps of a card stock strip (about 3/8" wide) to better fit the larger top opening.

The engine tube hole was cut out just inside the pencil line for a friction fit of the ST-7 tube.

6 comments:

  1. I'm curious about two things:
    1) Why do you need the layer of Future on top of the Krylon? That's just acrylic on top of more acrylic. What does the additional layer of Future provide in this case?
    2) It looks like you're doing all the clear coating before cutting and folding. Would it not be better to do the final Future coat (if nothing else) after shaping and assembly? I'd think the cockpit canopy at least would be easier to manage with fewer layers of gunk on it. Honestly, I'm just guessing though.

    Thanks!

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    Replies
    1. Hi Neil,
      I did the final (third) brush coat of Future because the card stock didn't seem sturdy enough. The last coat of Future did help. I was guessing (too) and it worked. I knew if I screwed up I could print another sheet.
      I score the parts after clear coating. It hasn't been any problem at all, I use the 110 lb. Georgia Pacific card stock from WalMart. I would think clear coating the parts after cutting and forming would be harder. But do what works for you.
      I'll clear coat, score the folds then cut out the parts.

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  2. What about the glue tabs? Does the glue still hold well to the tabs after the coatings have been applied?

    ReplyDelete
    Replies
    1. I guess you sand those to rough them up a little?

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    2. Hi Glen,
      I masked off the glue tab locations on the body shroud before spraying. When I brushed on the final Future coat I avoided all the areas that would get glue.
      I didn't have to rough anything up for gluing.

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