Trimming Plastic

To model Apollo 15, I have to remove the 4 ullage rockets from the Interstage wrap, and then patch the holes. Tim Van Milligan of Apogee Components recommended cutting patches from a second wrap; the question then became just how to get the patches to fit and to look good.

My first attempt: cut a patch that was too big, place the patch behind the wrap, and line up the stringers and other molded features. The slightly different plane is makes the patch too obvious, though. On to a second method: cut the patch so it fits perfectly inside the hole from the ullage rocket. This seems to be working, despite requiring much more precision and being much more tedious. It's now just a matter of being patient: start with the patch very close to the right size, but perhaps ever-so-slightly too big, and trim a thin sliver at a time until it fits, carefully ensuring the stringers stay aligned. With luck (shouldn't take too much), a tiny bit of filler and a coat of primer will complete the illusion.

The Joys of Tools

It sure is helpful to have good tools. It's even more important when you have someone who knows how to use those tools!

As yet another diversion in the Saturn V build, I'm working on an interesting two-stage rocket. More on some of the interesting bits later. For now...

The booster will be a D12, the sustainer will use an 18mm blackpowder motor. The booster's body tub is 35cm long, BT-80; the sustainer is BT-60. A transition between the two is needed, with a hole bored through to enable sustainer ignition. I have a 60-80 transition from BMS that just needs the hole.

How to bore the hole? I'd like the hole to be tapered, fairly smooth, dead center, and straight through. I don't have a drill press, a lathe, or a milling machine, and I'm certainly not trusting my hand drilling skills for this. (Yes, in fact, I only really need the two ends to be centered up, and the first, oh, couple of centimeters to be straight along the axis. Still, I'm not trusting this to my hand drilling!)

While checking with various friends, I ended up scheduling a business trip east that included a weekend swing by my parents' place for a visit. Dad has a small workbench drill press. He doesn't have quite the right size drill bits or mills, but he does have a couple of hole saws that are close. To make a long story a bit shorter, between the drill press, the hole saws, and the mill, along with Dad's skill at jury-rigging things and adapting tools and techniques to purpose, we have a hole that's nicely centered up, fairly well tapered, cleaned out of all the excess stuff in and around the edges (hole saws leave a plug in the middle of the work if you don't saw completely through—and the saw, though deep enough for our job, is only about 70% of the length of the transition), and ready for final fitting to the two motor mount tubes.

Pictures coming soon to the Nescorna Rocket Works Web site.

Good tools, good skills.

Cutting Wraps

Minor mistake: I chose the wrong sequence for cutting out the wraps. It should be obvious (shouldn't it?) that you start on the easy one, and work on progressively more difficult ones, not the other way around. Oops. I started on the hardest wrap.

Luckily, that wrap, the Interstage wrap, will likely end up as the fodder to patch the ullage rockets I'll remove from the other Interstage wrap, the one I actually did cut out last.