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Balloons for tube making?

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HyperSpeed

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I need to make some motor liners which fit the inside tube diameter. I have heard that you can use long balloons inside of the sleeve to do this.

I want to give it a try, but I want to make sure I use balloons which are thick enough and also long enough. Liner lengths will be up to 28" and around 2" diameter.

Anyone know where I can order the right type of balloons for doing this?

I was afraid the standard party shaping balloons may pop trying to do this.
 

Gillard

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i've never heard of using balloons to make tubes, but ithink your right about the party balloons. would it not be easier to go to a wood store and buy a pole of the correct diameter, or if the pole is too thick, attach the pole to a drill and then sanding down to size.
 

HyperSpeed

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The "Rocket Team Vatsaas" web page has an article on forming tubes using balloons:

http://www.vatsaas.org/rtv/construction/tubeform/tubeform.aspx

According to the page, they used "a LARGE party balloon -- 36 inches round, purchased at a party supply store."

-- Roger
That's a big diameter tube which they made. After some thought, I think I will try the wood mandrel. The problem is, I will probably have to sand the tube back down to get it to fit snugly.
 

MarkII

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How about making the liners by wrapping material around a spent motor or a reload case? If one spent motor isn't long enough, try taping several of them together end to end with scotch tape or clear package tape. You could also push a thin dowel down through the series of joined motors to help hold them together.

Mark \\.
 

Peartree

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How about making the liners by wrapping material around a spent motor or a reload case? If one spent motor isn't long enough, try taping several of them together end to end with scotch tape or clear package tape. You could also push a thin dowel down through the series of joined motors to help hold them together.

Mark \\.
Even cheaper, I often join spent 24 mm casings with spent 18mm casings. White or yellow glue locks them tight.
 

FROB

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I tried something similar for fiberglassing the inside of a large nose cone and coupler, with very disappointing results. It got very messy very quickly, and after many attempts, I gave up on the balloon and just kept pushing the soggy fiberglass into place with my gloved hand and various squeegees till the epoxy gelled.
I later had some success at inside molding fiberglass tubes in a polished aluminum form tube, using a section of bicycle tire inner tube as a balloon, but getting the darn thing out proved to be a real b****, even with the release film and lubricant.
It probably works better with stiffer materials like paper which tend to roll into a neat circular shape, but considering the difficulty in extracting it after, i'd suggest the normal mandrel method might be less trouble. Or search for an appropriate size of off-the-shelf tubing- depending on the size you need, vendors like Totally tubular, Aerocon, or others may have what you need.
 

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