Fixing an Oops :)

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Papa Elf
Jan 21, 2009
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Penns Creek, PA
I did not notice this till I was packing up the car after the last CMASS launch. My Ladyrobin suffered some damage during the last flight. Looks like when I set the ejection charge down, it was seated so the top of the charge was facing the airframe. The 2 gram charge I used almost completely blew out the side of the airframe tube :eek:!!!. I know I am not the first one to ever do this, but this is the first time I seen it happen. Now time to fix the Oops.

The attached two pics show the damage.


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First things first, fixing the buldge. This is used with a norml electric sander. of course the fiberglass is sanded off so that will need to be replaced. Also, as I figured the thickness of the airframe at the peak of the mountains is very thin.

Since the wall is so thin, I decided that I want to add a fiberglass patch to the inside of the airframe tube. I used 5 minute epoxy for this because its thicker and dries faster, and since its inside the airframe, does not have to be pretty. During the fitting the patch, the thin airframe did crumble, so I used the epoxy to fill in the holes. I also used the epoxy to fill in the cracks on the airframe.


Once the five minute epoxy was dry, I once again sanded the surface, and then installed the top layer of fiberglass. This time I used the normal thin slow cure epoxy resin.


I have whole rockets that look like that. Patches on top of the patches....
Did some more work on the repair. I sanded the fiberglass so its nice and smooth, being careful not to sand into the glass. then I covered the repair with bondo.

The next day I sanded the bondo, Followed by some primer.

I am pleased with the results. going need a couple touch ups with bondo but soon it will be hard to tell that a patch was put on the tube :)





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