Thursday, January 14, 2021

Semroc Laser X, KV-33 Build, Part 6, Fin Spikes & Carded Shroud

Now that I'm using thicker fin stock, the toothpicks on the outside edge looked spindly. I decided to go with a 1/8" dowel.

On the left: Why do they use overly sticky glue on the labels? I had to use some Goo Gone to remove the paper.

To start, rough taper the dowel ends with a pencil sharpener.




Clean up and smooth out the ends with 220 then 400 grit sandpaper.

On the right is my older Laser X showing the black toothpick next the to the new 1/8" diameter dowel.

Scissor cut shroud arcs are never perfectly smooth.
TIP: Run your fingertip around the curved shroud cut and you might feel an uneven lip edge.
You can smooth the arc a bit with some 400 grit rolled over a fingertip.






GOTCHA:
A dry fit around the ST-5 tube showed the the shroud was small!

Good thing I scanned the shroud before cutting it out!
I'll load it into Corel Draw and enlarge it a bit.

2 comments:

  1. As for dealing with shrouds, one could also use online tools like:
    https://rocketry.gonnerman.org/shroudcalc.html

    ... and of course there's also the somewhat more involved route -- work out the required formulas, then plugging in the numbers into an electronic calculator* (or go full "old fashioned" and use a slide rule), then draw out the shroud using a compass.

    * if your calculator isn't a scientific one with the trig functions, you could always use lookup tables (books like the CRC Handbook come in handy from time to time).

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    Replies
    1. Hi Naoto,
      Thanks for the link - My go to for home print shrouds is payloadbay.com, then hit the "Tools" button.
      The reason I brought it up on the blog build - A kit supplied shroud should be the right size. Shrouds are difficult enough to form and look good on a finished model. I wish vendors (big and small) would include a second card stock shroud in their kits.

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