The card stock centering rings were a loose fit on the inside of the couplers. Once again I built up the outside diameters with a bead of white glue on the outside edges.
These were "press-fitted" into the couplers on the flat surface of my cutting board.
I wanted to be sure they were flush so I only tacked them in place in four places. This would still allow me to make any adjustments as they weren't totally glued all the way around.
I've been using Q-Tips more and more when building. They pick up any overflowed glue after smoothing out the partial fillets with a rounded dowel end.
I let the ring dry inside the larger body tube to insure the coupler was glued perfectly round.
The instructions have you tie the attachment string before gluing the ring in place. I decided to do it afterwards. This was the string thickness wouldn't be in the way when I was leveling the ring flush on the flat work table.
The instructions have you tie the attachment string before gluing the ring in place. I decided to do it afterwards. This was the string thickness wouldn't be in the way when I was leveling the ring flush on the flat work table.
Here's the string tied through the two laser cut holes.
I didn't use shroud line string, I can assume the instructions meant to use 5" cut from the supplied parachute shroud lines.
I had some stronger black cord and used that.
Time spent on build: 1:00 build up centering ring diameters and glue to couplers
Total time on build so far: 5:15
Sorry - Part 7 of the build is listed ahead, between parts 10 and 11! Scroll up to find it. I skipped it by mistake and can't change the post dates.
Hello! FWIW the coupler on my Skylab Saturn V was extremely difficult to slide in place. Given the rather poor fit of a few parts on this kit, I wanted to make sure it would go in before actually gluing on the centering rings. I sanded a light bevel with 320 grit on the outside edge of the coupler tube and the inside edge of the airframe. Wasn't really easy but was able to get it in place.
ReplyDeleteYou are probably talking about the reinforcement ring inside the low end of the main tube. Check out this blog post: https://modelrocketbuilding.blogspot.com/search?q=reinforcement+ring
DeleteHere's another instance of a tight ring from the #1969 Saturn V kit: https://modelrocketbuilding.blogspot.com/2019/05/estes-saturn-v-1969-build-part-7.html
DeleteNo, this is the coupler with the centering rings, aft end of the third stage.
DeleteAlso: the original centering rings got trashed by my cat knocking over a cup of coffee onto the work surface. I made new ones from two layers of 3/32" balsa, epoxied with the grain at right angles. The surface to which the shock cord attachment knot is glued was reinforced with 110 lb cardstock wetted with epoxy, as I didn't trust the cord not to pull thru the balsa. Though it's a fair bit heavier, I'm using epoxy a lot because (a) I'll probably use slightly larger motors than the Estes ones and (b) I don't have to worry about the glue grabbing too quickly. Epoxy also doesn't shrink, so there were no dimples where the MMT centering rings were glued to the main body tube.