Vacuum Bagging Tubes?

[Jack Stone]

Wondering if other folks have attempted to vacuum bag their cardboard rocket tubes.

But I've never found any articles on fiberglassing cardboard tubing.

Please share your experiences and feedback.

Goal is to beefup the structure without the weight penalty.

Assumption is that bleeder/breather - remove access epoxy, and ensure that the glass cloth makes strong contact to the surface consistently.

So again please share your thoughts and considerations.

Jack S.  

[Jesse Callaway]

That sounds like a fun experiment. If you think the cardboard fibers might absorb epoxy then a layer of parchment paper might help?

-jesse

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[William Kellermann]

Funny you can’t find articles on this because it’s really old school.  I am looking for an article I had about using a nylon stocking with resin to glass a cardboard tube.  If I find it I’ll post it here.  This was also done with phenolic tubes back in the day. 

There are a number of old timers who have a lot of experience with vacuum bagging who may chime in.  I also have Gene Engelgau’s 8’ curing oven but unfortunately it is in Nevada.

William Kellermann
wt...@me.com

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[Emma Humphries]

Have you seen Soller Composites' fiberglass sleeves which you cover with a heat shrunk plastic sleeve while it cures?

https://sollercompositesllc.com/tubular-sleeving/fiberglass-biaxial-sleeving/

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[Jack Stone]

Emma,

Yes 🚀

I’m using their products for my experiments.

I’ve done the Mylar and also the heat shrink tubing  previously on other projects.

What I’ve achieve strength vs. weight best results were with bagging for our competition sailplanes.

Since I have the equipment and the materials mostly I wanted to try it in my L2 build.

I ordered both size suitable for 4” tubing.

But after 30+ years it’s getting funky

Now waiting for my Gast parts.  

Found out that if I pressed the tube under vacuum it will collapse LOL.

So wanted to see the difference between fiberglass sheet and sleeve

Thanks,

Jack

Sent from my iPhone

On May 27, 2026, at 16:30, Emma Humphries <emce...@gmail.com> wrote:
Emma



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[Emma Humphries]

On Wed, May 27, 2026 at 10:04 PM Jack Stone <mediwh...@sbcglobal.net> wrote:

Found out that if I pressed the tube under vacuum it will collapse LOL.

Oh yeah, you'll want a mandrel for using the vacuum bag, and some sort of mold release for it! 

[Jack Stone]

Emma,

Mandrel are the two end tubes as you can see in the picture.

I’m using PartAll on them and Teflon tape on the other side.

Using a thick coupler tube to hold the tube

Jack

Sent from my iPhone

On May 27, 2026, at 23:55, Emma Humphries <emce...@gmail.com> wrote:



On Wed, May 27, 2026 at 10:04 PM Jack Stone <mediwh...@sbcglobal.net> wrote:

Found out that if I pressed the tube under vacuum it will collapse LOL.

Oh yeah, you'll want a mandrel for using the vacuum bag, and some sort of mold release for it! 

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