Epoxy... Cured or not?

[bronicabill]

I just posted a few hours ago in the “Recovery” forum about finishing up my latest MPR rocket build, an AeroTech ARCAS. One thing I didn’t mention at the time was what I experienced with my kevlar shock cord in the lower section.

Since I converted this model to dual-deploy, much of the original building instructions were not followed. One of those was the need to reinforce the upper motor mount ring with epoxy after insertion in the lower body tube.

I used 30-minute epoxy, applied with a Q-tip taped to a long rod. I would have preferred 5-minute epoxy, but the 30-minute was all I had at the time (that issue has now been corrected!)

So why do I make this post? Well, even though I glued that upper ring in place about 2 weeks ago, I still had a problem!

When I attempted to pull out the kevlar shock cord tonight to rig the drogue chute, the kevlar cord was stuck to the epoxy on the upper motor mount ring! Thankfully it was not a serious bond, and a good tug pulled it free, but a lesson was learned here... either use 5-minute epoxy for the task, or be freakin’ sure the slower epoxy has cured COMPLETELY before letting your shock cord drop back down into the lower body tube!!!

 

[teepot]

I had that happen once too. A lot of pulling freed it. Lesson learned.

 

[OzHybrid]

I had that happen once too. A lot of pulling freed it. Lesson learned.

fit an automatic food dispenser and get the cat to check it at 5 minute intervals. When the footprints stop it's cured.....