While removing a tight A10-3t motor, I pulled out the engine mount!
It had been glued in using epoxy, the only glue I thought would best adhere the BT-5 tube to the plastic Birdie interior.
On the left is the interior of the Birdie. On the right is the engine mount with the epoxy still at the top.
I went to my all-purpose glue for adhering plastic to a body tube, Beacon Fabri-Tac. I left the old epoxy in place.
A bead of Fabri-tac was placed inside the top interior of the Birdie.
The engine mount assembly was pressed into the Birdie making sure the launch lug was slipped between the ribs at the top of the body.
I let the glue dry before giving the engine mount a good tug. The bond seems strong!
It was loaded with an A10-3t for an upcoming launch.
Chris pulled my birdie apart a few years back. I epoxied it back together, but it hasn't flown the same since. I should figure out why someday.
ReplyDeleteWe may need to investigate what type of plastic is used in the body of the birdie -- this might provide us with a clue to what adhesives would be best. The epoxy probably failed because it tends to dry hard, while the material of the birdie flexible -- eventually it ends up "peeling away" from the epoxy. IIRC Fabri-tac remains flexible, so it might work a bit better (though might not provide a permanent bond). Perhaps scuffing the mating surfaces could give more "tooth" for the glue to hold on to the material?
ReplyDeleteHi Naoto,
DeleteThe original epoxy lasted for 10 years - for a tube to plastic bond I consider that a pretty good bond. For now the Fabri-Tac seems pretty strong. Time will tell!
I do recall back when Polar Lights released a plastic model of the Jupiter II (from the 1960s Lost in Space TV show), a lot of people were having problems with gluing the kit since the kit was made of ABS rather than the usual polystyrene. Usually plastic model glues work by chemically "melting" the plastic of the parts -- when the solvents evaporate the plastic re-hardens and the parts are essentially "welded" together. ABS was resistant to the solvents found on the usual plastic model glues, so you needed to use a glue with stronger solvent.
ReplyDeleteFascinating video on how shuttlecocks for badminton ("traditional" type rather than the cheaper synthetic ones) are made.
ReplyDeletehttps://www.youtube.com/watch?v=XS7HLzQZFgk
Hi Naoto,
DeleteGreat video. I guess that's why real feathered Birdies are so expensive! The wind tunnel and final feather angle adjustments was interesting.