Brief:
The G3 is a bare-bones 3FNC dual-deploy kit with high-quality G10 fiberglass parts.

Construction:
The kit comes with a gel coated 3:1 ogive fiberglass nose cone, two sections of 3" G10 airframe tube (22" long payload and 44" long booster), 3 clipped-delta fins, a 12" long 54mm MMT, two centering rings, five bulk plates, and a 6" coupler/avbay. All of the flat G10 parts are 3/32" thick.

To this I added a 20-foot section of 1/8" Kevlar® shock cord, an Aeropack motor retainer, a 50-in Top Flight parachute, a Nomex® chute protector, a 15-foot section of TN, eyebolts, all-thread, and rail buttons.

There are no instructions, but there's a wealth of information about how to assemble PR kits on various online rocketry forums. I used the epoxy injection method, where you drill or file small holes in or near the fin slots so you can inject internal epoxy fillets into the tight space between the inside of the airframe and the outside of the MMT at the fin roots. (An alternative is to extend the fin slots and build the entire MMT-fin assembly outside the airframe.)

(As an optional step, I cut down the trailing edge of the fins with a Dremel cutoff wheel to reduce the risk of landing damage and because I thought it looked cooler. This probably moved the CP forward a couple of inches, but the rocket is so long and the CG so far forward that it would be tough for it to be unstable.)

I started by sanding all areas that would contact epoxy with 60-grit sandpaper. (Make sure to wear a fiberglass mask, gloves and a long-sleeve shirt. You don't want to breath fiberglass dust and it's very itchy.) The centering rings and bulk plates were a bit tight, as was the Aeropack on the MMT, but a quick pass or two with a Dremel corrected that. (Sanding down the G10 takes forever by hand, so the Dremel is definitely a win here, but be careful not to remove too much.)

Note I used Devcon 30-minute epoxy throughout, but you may want to invest in a higher-quality epoxy like West Systems -- it's stronger, and more convenient since you can easily tweak the viscosity as needed and use additives to increase strength.

After everything was sanded, I then carefully dry-fitted the fins, rings, and MMT into the booster and tacked the lower ring in place with thick CA. You should mark which of the fins go in which slots in case there's any difference in fit, because you don't want any leaks when you inject the internal fillets. I then epoxied the upper centering ring on the MMT, followed by the Kevlar® all along the MMT, passing it through a notch in the upper centering ring. (I used 1/8" Kevlar® but in hindsight I think 1/2" Kevlar® ribbon would be a better choice.) You're trying to get the fins to fit perfectly between the rings with no gaps.

After that had cured, I epoxied the MMT assembly into the booster with a ring of epoxy just above the fin slots and put the fins in dry to make sure the MMT was positioned correctly. After letting that set, I put a fillet around the bottom OD of the lower CR and then tacked the fins onto the MMT with 5-minute epoxy.

Now the injection. Using epoxy diluted with alcohol in a 10cc syringe, I injected epoxy through the hole on each side of each fin, two at a time, until that space was full (each fillet took about 7-8 cc.) You can see the shadow of the fillet if you hold the rocket up to a bright light. Make certain your holes are large enough to pass the tip of the syringe and clean your syringe with alcohol between sessions.

I then added external fin fillets using epoxy mixed with cabosil.

Epoxying the bulk plates together and the NC bulk plate into the NC shoulder (after adding an eyebolt) completed the assembly. I drilled the bulk plates for two pieces of 1/4" all-thread in the usual manner to form the avbay, and held it onto the payload section with 2 PML plastic rivets.

Finishing:
Other than light sanding with 320-grit paper, there's nothing to fill on these G10 kits unless you are more obsessive than me. I used Rustoleum auto primer followed by Rustoleum cobalt metallic blue and got a very nice finish. A coat of Future floor wax added some gloss, and I put on a strip of chrome adhesive Monocote to aid visibility.

I waited until after painting to put the Aeropack on, JB Weld per the instructions. I had previously masked the rail button attach points, and two holes were drilled and tapped for them. After drilling rivet, altimeter vent, shear pin, and relief holes in appropriate places, I was ready to fly.

Construction Rating: 4 out of 5

Flight:
I decided on a CTI 54mm J210 for the first flight. Since the CTI delays are pretty accurate, I decided to use motor ejection at apogee and let my RRC2 handle just the main deployment. I put some folds in the Kevlar® shock cord between the booster and the avbay and taped them with masking tape to reduce the shock loads, followed by a big wad of masking tape covered with duct tape at the point where the Kevlar® hit the lip of the booster tube. I prepped the main charge and the avbay, then attached the TN to the avbay and to the NC, folded the chute, and wrapped the whole bundle in the Nomex®. It was a snug but acceptable fit in the payload section. The Aeropack, of course, made installing the motor a snap.

Recovery:
The boost was straight and the J210's long 4-second burn was awesome. Drogueless descent looked acceptably stable (descent rate was around 65 fps), and the main popped out right on schedule, slowly lowering the rocket to a perfect landing. Somehow the 9V battery came loose after main deploy, but the RRC2's flight log reported an altitude of 4410 feet.

The only damage was a tiny amount of fraying in the Kevlar® shock cord near the top of the booster tube. More duct tape here is in order, and using wider Kevlar® ribbon and some TN in this section to provide some stretch would be a good idea.

(I'll mention that on my second flight on a CTI J295 a couple of hours later, the rocket came in hard when the battery apparently came loose at motor ejection. Landing on the unforgiving desert floor, one fin was broken out of its slot but the rocket was otherwise undamaged, and the fin was easily fixed after I chiseled off the old fillets. Landing on grass, it probably would have survived without a scratch.)

Flight Rating: 4 out of 5

Summary:
As my first G10 fiberglass rocket, this was a learning experience. One could imagine a more complete kit and maybe some instructions, but building from parts provides a lot of opportunity to learn new techniques (or make new mistakes?) and pick recovery components to taste. G10 has its challenges (I got several cuts and abrasions, not to mention itching) and it's not that light, but you can't beat it for smoothness and durability.

On the weight issue, note that the kit specs say built weight is "about 4 lbs". The parts alone weighed more than that out of the box, and mine tipped the scales at over 5.5 lbs ready to fly. That said, this rocket just begs for large motors; I definitely see some big Ks or maybe even Ls (and a tracker) in its future!

Overall Rating: 4 out of 5

Other:
You can't pay enough attention to battery retention, as my second flight with the G3 demonstrated. Select your booster shock cord carefully; if it's epoxied to the MMT you won't have another shot at it.