# 13mm fiberglass tube

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#### David Schwantz

##### Well-Known Member
Does anyone have them available? Checked, Wildman. Madcow, Mach 1.

#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
The FG tubes that are used in FAI competitions are hand-rolled over a mandrel. Not a commercial item AFAIK.

#### David Schwantz

##### Well-Known Member
Thanks for the replies, I am doing a 13mm MD project. I made it in cardboard already, but would like glass instead.

#### georgegassaway

"MD project"?

If you need more strength/stiffness but increasing the diameter and mass a bit would be OK, you could consider wrapping 3/4 oz glass cloth around a paper 13mm tube, using a good quality epoxy resin. Just I can't tell from your posts what the specific need is for a fiberglass tube.

Worst-case, 13mm drill rod could be used as a mandrel for making an all fiberglass tube. After a good coating with spray on mold release before layup, the ID of the resulting tube should work for holding a 13mm engine.

#### David Schwantz

##### Well-Known Member
Just prefer the toughness of glass instead.

#### caveduck

##### semi old rocketeer
Having personally made all-glass competition tubes, I can vouch that it's a certain amount of work. Usually you do it to *reduce* mass - 3 wraps of 0.7 oz cloth will end up at around 1/2 the mass of a paper tube but it's pretty fragile and bendy. You can use more wraps or heavier cloth to get a sturdier tube, or just glass over a paper tube like George said. You'll get a stronger tube doing that if you peel off the glassine layer first (if there is one).