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homemade tube support and tube damaged


fr3dopyrox

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I pressed a rocket with an homemade tube support and bottle jack 4tons,but i haven't gauge!, When I removed the tube of the support, he was a little damaged, in your opinion I pressed too hardly? the tube is a little damaged and it's only a 4tons bottle jack press; how it possible? thanks a lot....

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An image of the tube and of the support will help. I'm damaging a lot of tubes, bending spindles, etc... Learning to make and use my own tooling. First suspect: Too much presure. Second suspect: Too big increments. Third suspect: Bad tube or support.

Edited by Baldor
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Everything Baldor said could be the case. Also consider what size rockets you're making. Even a 1" ID rocket would be getting over 10,000 psi with that jack, which is too much for many tubes to handle.

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If you are going to press with a bottle jack, you need one of two things, preferably both:

 

A force gauge: http://www.skylighter.com/fireworks/arbor-press-force-gauge.asp

 

Install a manometer in the jack: http://www.albroswift.com/jack.htm

 

There is no way you can know what pressure you are applying without those. Both you can make yourself or bought finished.

 

I missanotated the reading on the manometer when calibrating for 3/4" tubes. I wanted to apply 6500PSI, I finished applying 15000PSI without a sweat with a 6T press. I not only bursted the tube, but also bursted the tube support. I didn't feel I was overpressing until I saw the support open.

 

I also made some tests with bentonite and a 20mm diameter, 1mm wall thickness steel tube. You can make the tube swell a few mm without a sweat.

 

What I'm saying is... You can apply an enormous force with a bottle jack, and you can't feel it. You need instruments to measure it.

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I once saw the press tool to make 3" gerbes. The tube support bit was basically a 6" diameter piece of hardened tool steel with a bore for the card tube. Sometimes the sleeve needs to be strong, Maybe stronger than split pipe and hose clips.

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