I was going to wait and do all the pins at the same time, but I'm still figuring out what to do with the nose cone, so the nose cone pins will have to wait.
Here is how I did the alignment pins for the av-bay to booster and av-bay to payload tubes. The advantages of using the pins include:
Start by aligning the tubes and taping them in place so they stay put. You have to make sure the tubes stay together tight. It doesn't matter if there is some rotation after drilling the hole for the single pin on the payload tube, but the two pins on the booster have to be drilled without any rotation or movement. I use a brad point drill to drill the holes. I find the brad point works best because it's easy to see that it is starting right on the joint and it cuts through without tearing up the fiberglass.
Rough up the inside around the holes so the epoxy sticks well
I guess you could use wood dowels, but I like the fiberglass rods. They are harder and I expect them to outlast the rocket.
I clamp the vacuum hose in place to pull the dust and cut pieces off the rod with the Dermal. I do it over the hole in the 2x4. The shop vac is pretty strong and this way the pieces drop in the hole and can roll away and gets sucked up by the vac.
I mix up a little 5 min. epoxy, put a little in each hole and tap the rods in place with a small hammer. The rods are a snug fit and I tap them down until they extend slightly above the outside surface. I'll use a file to cut them down smooth with the surface.
WARNING - If you use a Dremal to sand them down, be very careful you don't overheat the fiberglass rod. The resin in the rod will ignite if you get it too hot and then you have to get the slow smoldering fire out or your rod ends up as a loose bunch of black glass fibers. Don't ask.....
After the rods are in, use the last of your 5 min. epoxy to coat the inside where you roughed up the glass. This probably doesn't keep the rods in place so much as it eliminates sharp edges where wires and such could catch as you insert or remove your electronics.
Here is how I did the alignment pins for the av-bay to booster and av-bay to payload tubes. The advantages of using the pins include:
- Even though the av-bay is symmetric you can't install it upside down because there is one pin on the payload and two on the booster side.
- Any shear pin holes will be perfectly lined up, no spinning and twisting to get holes aligned.
- As with shear pins, any rivots/screws used to attach the payload tube will also be automatically aligned.
Start by aligning the tubes and taping them in place so they stay put. You have to make sure the tubes stay together tight. It doesn't matter if there is some rotation after drilling the hole for the single pin on the payload tube, but the two pins on the booster have to be drilled without any rotation or movement. I use a brad point drill to drill the holes. I find the brad point works best because it's easy to see that it is starting right on the joint and it cuts through without tearing up the fiberglass.
Rough up the inside around the holes so the epoxy sticks well
I guess you could use wood dowels, but I like the fiberglass rods. They are harder and I expect them to outlast the rocket.
I clamp the vacuum hose in place to pull the dust and cut pieces off the rod with the Dermal. I do it over the hole in the 2x4. The shop vac is pretty strong and this way the pieces drop in the hole and can roll away and gets sucked up by the vac.
I mix up a little 5 min. epoxy, put a little in each hole and tap the rods in place with a small hammer. The rods are a snug fit and I tap them down until they extend slightly above the outside surface. I'll use a file to cut them down smooth with the surface.
WARNING - If you use a Dremal to sand them down, be very careful you don't overheat the fiberglass rod. The resin in the rod will ignite if you get it too hot and then you have to get the slow smoldering fire out or your rod ends up as a loose bunch of black glass fibers. Don't ask.....
After the rods are in, use the last of your 5 min. epoxy to coat the inside where you roughed up the glass. This probably doesn't keep the rods in place so much as it eliminates sharp edges where wires and such could catch as you insert or remove your electronics.
