Need Help Repairing My 1st HPR

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.


May 24, 2004
Reaction score
OK. Im new to HPR and I need your advice. Heres a pic of my first high power rocket, a BSD CDN Sprint. On it's first launch I certified L1 (NAR) ! Well on it's 2nd flight I got this damage. :mad: Would this be called a crimp, a wrinkle ?
The forward (larger) wrinkle is just forward of the centering ring. As you can see the aft wrinkle is much less pronounced. Actually it still seems like its strong enough to fly as is and I've gotten differing views from guys in my club.
What do you all think ?

I guess the best way to fix this is to cut the body off forward of the wrinkles and rebuild the entire fin / motor mount section....uugh. Do I have any other options ? I saw one hint on Essences where someone said you can poke small holes right on the crease line , fill with thin CA , sand and repaint. Is that a decent idea ?

Any ideas you all might have would be greatly appreciated as I'd like to keep this, my L1 bird, flying a bit longer.

One way or another this bird MUST FLY AGAIN !

Thanks for your help.

- John
If you have enough space between the forward centering ring and the large wrinkle in the body tube, cut out the bad section, and attach the two together with a copuler. As for the smaller wrinkle, I think if it is between the two centering rings, it should be OK the way it is, but you can make very small holes and fill them with CA fo extra protection. Its like making rivets for the body tube.
I have a BSD Thor that got a bit of a kink in the tube from one flight, although it wasn't as pronounced as yours. I chose to reinforce the crimped area by sliding & epoxying a coupler inside the damaged area. That might be more difficult to do on your Sprint though unless you've got small hands/arms. Be sure to sand the coupler real well so it can slide all the way through the body tube!

hope you can fix it
looks like she came down pretty hard
is it possible the the chute is too small?
The idea of putting a coupler inside the tube to reinforce it sounds like a good plan! Make sure you put lots of CA around the coupler , to stop that from doing the same.
I would score the tube and then peel off half the thickness over the wrinkle then stick a couple layers of cloth in there and epoxy it down
OK. Bear with me here. Obviously all of you are more experienced than I am. I think there are some good suggestions here but Im afraid I dont fully understand them. The idea of putting a coupler inside the tube to reinforce it seems like the most straight forward way of going about it however would this still apply if the wrinkle is right at the forward centering ring ? Thats where it is if my calculations are correct. I'm fairly sure this is the case so I guess after I cut the body tube (couple inches forward the wrinkle?) I need to somehow push the wrinkle out so that the coupler will fit all the way down to the centering ring , correct ? If so can I then sand the wrinkle on the outside and put on some touch-up paint ? Im sure Im coming off like a newbie ie trying to keep it looking good but I may as well try eh ?

Also, after I repair this there is still going to be a small amount of bend in the tube overall. How much will this affect performance ?

Thanks for all your help,


I think I understand your idea but how hard is it to get centering rings away cleanly from the bodytube if theyre epoxied in ? AM I right in saying that what I'd end up with is the fins ,motor tube and centering rings ? Would I cut the fillets off of the fins too ? Also wouldnt these slots cut into the new tube extend aft of the fins ? How wouldnt I deal with that ? Thanks.

Here's a pic just before it's maiden on my homebuilt rail launcher...
This is what I would do . Score around 1 1/2" - 2" above the wrinkles with a exacto knife/stanley ect , and below the bottom wrinkle. Peel a bit of the Bodtube away , not too much though! Using 2oz Fibreglass , glass the section you just peeled away . Leave to cure (24hrs at least) , sand , then repaint.

Does this make sense ? Score a line maybe 1" above the wrinkle and then score another line maybe right above the fins (1" below)? Since I've never done it, how do you then pull away the paper ? How much of the paper do you pull off, half maybe ? This idea looks to be the easiest for me as I dont have any couplers . However would I be able to bend out the crimp to get the tube straighter this way ? Would the oucome look pretty nice or what ?
Also, can the right kind of cloth be found any place other than a good hobby shop ? And should 30min epoxy be used ?

Thanks (a lot of questions),
As far as I know you must use a Epoxy that has a 30min pot life or more , this means when it's mixed , you have 30min working time. But you can get Epoxy that is designed for fibreglassing (Its much thinner than normal 2 part Epoxy) Like West Systems .
You should be able to pick up the Fibreglass Weaved Cloth at most automotive stores , car shack ect. I think model shops that specialise in BOATS should have it ! The finished product will look nice ! Score the lines in your tube (not too deep) , then score a slit from the top score to the bottom and peel away . Take about a quarter to a half off , the glass will replace it .