Advice on repairing mangled top of body tube

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Joined
Mar 5, 2017
Messages
1,950
Reaction score
851
For some reason my ejection charge blew off (or blew apart) the nose cone on my glider
and made a mess of the front of the engine tube right where it meets the pylon (2nd photo).

Any suggestions on the best way to repair this?

IMG_9918.jpgIMG_9919.jpg
 
I can't. The front edge of the pylon goes right up to the (former) edge of the tube.
Seems like you should be able to cut it a few inches back, drop in a coupler & a new bit of BT to bring it back. Just need to go far enough to be sure the NC can seat well.
 
Seems like you should be able to cut it a few inches back, drop in a coupler & a new bit of BT to bring it back. Just need to go far enough to be sure the NC can seat well.

Just got a dremel so maybe I can cut under the pylon just enough to do just
that. Thanks!
 
You might try a razor saw. They're a little more controllable for small jobs like this.

Might be easier than a hobby knife. I'll still need some kind of cutting guide tho. Can't easily wrap paper around the tube because of
the pylon and impossible to get an Estes tube cutting guide onto there. I'll rummage thru my spare parts bin to see what I can
come up with. Thanks for the suggestion Steve.
 
Might be easier than a hobby knife. I'll still need some kind of cutting guide tho. Can't easily wrap paper around the tube because of
the pylon and impossible to get an Estes tube cutting guide onto there. I'll rummage thru my spare parts bin to see what I can
come up with. Thanks for the suggestion Steve.

When I bought one of my razor saws it came with a small aluminum miter box.


Steve Shannon
 
Only other fix would be to carefully smooth out all the crinkles (use the nose shoulder as a mandrel as needed) and then soak with CA. When dry, sand smooth. If you need a bit of filler in the process, baking soda works well with CA.
 
Only other fix would be to carefully smooth out all the crinkles (use the nose shoulder as a mandrel as needed) and then soak with CA. When dry, sand smooth. If you need a bit of filler in the process, baking soda works well with CA.

That sounds the least destructive and risky, glad I hadn't started on the fix yet. Worst case if it doesn't do the job is I'll have to fall back to hacking off the damage. Thanks for that tip on baking soda and CA btw.
 
That sounds the least destructive and risky, glad I hadn't started on the fix yet. Worst case if it doesn't do the job is I'll have to fall back to hacking off the damage. Thanks for that tip on baking soda and CA btw.

It's an old plastic modelling tip - pack the gap with baking soda, smooth, and flow in thin CA. It actually has a sanding density similar to styrene.
 
Turned out pretty decent considering the "before" damage. Some straightening with
a dowel and thumb followed by epoxy putty and homemade filler (polycrilic & baby powder)
and endless rounds of sanding brought it back to better-than-new. Took the tip to insert a
coupler to strengthen it and re-round the tube. Thanks everyone for the advice.

B4-After.jpg
 
If it happens again, I'd probably just pull off the whole tube and glue on a new one. Since the tube was beat up, you could just rip the tube off of the motor mount and glue it into the new tube.
 
Back
Top