General Fiberglass Tips

I've worked with a bit of fiberglass through the years, in various applications. The G-10 type tubing and sheet sold for rocketry are very strong and durable. They are also heavy. My 2" Renegade (~1.3x upscale) weighs in around 2½ pounds with its heavy fiberglass nosecone. H-flights are marginal around 1500 feet.

Some of my minimal-shop-tool methods:

• I cut the tubing and 0.125" sheet with a fine-toothed hacksaw blade. I also use a jigsaw with an abrasive blade from Remington made for fiberglass (Home Depot,etc) to cut sheets. Regular drill bits are fine, just cut slow and with little pressure to keep the edges from fraying. When possible, drill smaller holes and use a round file to finish them. Fin slots are a pain, but far from prohibitive. I start them with drilled holes, then slot with the aforementioned saw blades. A *sharp* razor will finish rough or crooked cuts surprizingly well.
• I typically cut fins with a hacksaw blade, and bevel them with a bench grinder.
• Centering rings can be cut from G-10 sheet with a holesaw, just be patient. If you can't find the correct diameter saw, don't fret. Cut the outside diameter large, and the inside small. Use the bench grinder to turn the outside down, and dremel with drum sanding attachment to work the inside.
• Always, always, always, use a respirator when sanding or grinding this nasty stuff. The dust does horrible things to lungs.
• The smooth factory finish must be sanded off in order for adhesives to bond well. Use 150 grit for areas like fin roots.
• I use slow-cure laminating epoxy for most everything I do. You'll find lots of arguments and opinions. Stay away from fast-cure epoxies, they are usually thicker and may not thoroughly adhere to the full surface area.

Build rockets from fiberglass tubes. They are nearly indestructible. I have one that has fallen from 3000' on a tangled chute on one flight, then came in ballistic from 5500' to core sample on another flight. It took nearly an hour to dig it up, but flew again without repair. (Really, I have witnesses.)

Submitted by Tim Smith