Tubes out of round

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jransbottom

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Hi Everyone,

Anybody have a good technique for fixing body tubes that are out of round? I just got an older kit off of eBay that the tubes aren't round anymore. No creases, just a little out of shape. Any ideas on fixing them?

Thanks in advance,

JR
 

astronboy

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Depends on the amount they are out of round, and what you are willing to put up with.

I recently build a rocket with an out of round tube: One end was worse than the other, so I made the 'bad' end the engine end. The centering rings dealt with the out-of-roundness issue. For the other end... I simply massaged the tube back into roundness. At least close enough for the NC to pop off easily.

In a far worse case, when I first became a BAR, I found my old ESTES GOBLIN in the bottom of a drawer. No fins, no cone, just a waaay out of round tube. Since my Dad built this for me as my frist rocket back in 1971, I really did not want to throw it away.

Solution: I stuffed the inside of the almost flattened tube with a full length of BT-55 tube coupler from Totally Tubualr, and glued it in. The rocket is a bit heavier, and I re-tested for stability. But she is fine, and flies very well!!

Fred
 

Fore Check

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Originally posted by jransbottom
Hi Everyone,

Anybody have a good technique for fixing body tubes that are out of round? I just got an older kit off of eBay that the tubes aren't round anymore. No creases, just a little out of shape. Any ideas on fixing them?

Thanks in advance,

JR
What size body tube is it?
 

DynaSoar

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Originally posted by jransbottom
Hi Everyone,

Anybody have a good technique for fixing body tubes that are out of round? I just got an older kit off of eBay that the tubes aren't round anymore. No creases, just a little out of shape. Any ideas on fixing them?

Thanks in advance,

JR
A short piece of coupler tube for that size, inserted into the tube. This can be incorporated into the MMT if desired, or placed mid-body, and let the centering rings and nose cone shoulder handle the ends.
 

jransbottom

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It's Estes BT-67 or Centuri ST-20. It's the Estes Mercury Redstone kit (#1921) from the mid to late 80's that used to be the Centuri Redstone kit.

JR
 
A

Austin

You may be able to just build it as is... with a motor mount at one end and a nosecone at the other, it may be just fine enough to fly.

Carl
 

powderburner

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Plan A
Work the BT into the shape you want, swab/paint the interior with mass quantities of CA or thin epoxy

Plan B
Use the kit's motor mount/centering rings to fix the rear end.
Find a length of larger-diam BT that will fit ahead of the forward CR but stops short of the front of your main BT (to leave clearance for the NC shoulder to slide into place).
Cut a slot in the larger BT to reduce the circumference, roll it smoothly and gently to compress it, and slip it into place as an internal liner (thin some water-based glue and paint the inside of the main BT before slipping in the reinforcement).
 
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