Building a CF Tube

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OverTheTop
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Re: Building a CF Tube

Postby OverTheTop » Sun Oct 06, 2019 11:54 am

Great result Joe!
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air.command
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Re: Building a CF Tube

Postby air.command » Sun Oct 06, 2019 2:35 pm

That tube turned out really nice joeman, well done! The epoxy to resin ratio is great. If you are adding epoxy to the outside I would recommend mixing it with microballoons before applying, that way you get a lighter weight finish and easier to sand as well. Though you would need to paint it a solid colour afterwards because the microballoons make the epoxy milky in colour.
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Aquaman33
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Re: Building a CF Tube

Postby Aquaman33 » Sun Oct 06, 2019 8:12 pm

This is an amazing project and the results look incredible.

I wouldn't dream of offering advice on how to build carbon tubes. :D

But have been fibre glassing some cardboard tubes recently and have had good success at extending pot life. After I have mixed the resin I poor it into a small plastic paint roller tray (from Bunnings). I then stand the tray on a frozen cold pack. I have an A4 sized thin flat cold pack designed for sports injuries. This keeps the resin really cool until its used and has a significant impact on pot life.

You may be able to incorporate something a bit like this in your process if you want to buy yourself some time.

Good luck.

joeman
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Re: Building a CF Tube

Postby joeman » Sun Oct 06, 2019 10:41 pm

Thanks guys for support - and advice.

Hi Air-Command
At first I didn't like the idea of getting rid of the nice CF pattern, but that idea of having microballoons softer surface means it will sand preferentially to the CF, which means easier to get that perfect looking cylinder. (After winding this tube, I like the idea of something easier to do). Something to mull over.

Hi Aquaman
Good idea RE: cooling. If I only had to make 4 x 200ml batches instead of 8 x 100 ml batches it would be nice. I am adamant that the Epoxy is curing a lot faster than a month ago on my first 2meter tube attempt. A few degrees makes a bit difference!

I have wondered if it might cause water vapour to condense out of the air and possibly spoil the Epoxy. Any thoughts on that?
I get heaps of frost on "everything" when I use Dry Ice...not surprisingly. mmm Perhaps I should invest it some cheap fridge of sorts that I can set the temperature above the dewpoint. Something to think about.
L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO

Aquaman33
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Re: Building a CF Tube

Postby Aquaman33 » Mon Oct 07, 2019 9:56 am

Have you considered using UV cured epoxy?

I have no idea of its strong enough for carbon tubes, but its very popular with people that make surfboards.

As long as you block out most of the UV in your workshop you can work with it for many hours. Then when your ready just put your tube outside in the sun. It then cures really really fast.

This video gives you an idea of how it works.



Because its activated by UV you don't need any catalyst, so no mixing!

sansspaceship
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Re: Building a CF Tube

Postby sansspaceship » Wed Oct 23, 2019 4:57 pm

Great thread - the engineering of the winder is fantastic!

Just an idea regarding surface finish, that I have used with general composites and is a little less maddening than going over it with a micro balloon mix. You can get a 3/4 ounce fiber glass and depending on the undulations one or two raps would flatten it out, and help to soak up any excess epoxy, and adding very little weight. Also give a little protection from when sanding, as you will know once you hit the toe everything goes sideways.

Additionally you could probably wrap with Teflon peel ply to help improve the surface finish again. (I must caveat that I have only recently got some of the Teflon release but haven’t ever used it), but have seen good results else where.

p.s. you are probably across this but with the micro balloons, the brown sands much better than the white.

Hope this helps, please keep sharing your journey.

joeman
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Re: Building a CF Tube

Postby joeman » Sat Nov 09, 2019 10:22 pm

Thanks for your suggestions. Haven't got to sorting out the finish.

I've been starting on the next thing to wind.... (while I ruminate over the way to "finish" the air-frame).



Code is VERY experimental... a lot of work to get it to do a "proper" wind job.

I'm thinking I'll just wrap 4 layers at 30 degrees...the nose cone is about 25degrees to about 90. But I cut it off because 90 degree orientation is useless. Then I'll create an Aluminium Nose Cone tip.

All taking a lot of time, but getting there!

Enjoy!!
L1 - Callisto (H133) - 11-Jan-2016
L2 - March Fly (1633K940) - 18-Mar-2018 - RSO


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