Carbon Fibre supliers anyone?

[garymck]

Per my earlier question regarding rotating tube rings, I've decided to make a new OTA out of carbon fibre.

Does anyone know of suppliers in Melbourne for the cloth and epoxy? Who's the cheapest etc.

Also wondering if anyone has done this before, what weight of cloth I should use etc.

At this stage I think I'll make a sandwhich design with a layer of balsa sandwiched between two layers of carbon. Any other ideas?

cheers
Gary

[MrB]

Can't help on Melb. supplier, but do remember seeing a very detailed description with heaps of photo's on the web somewhere years ago on how to make an OTA. Can't remember if it was glass or carbon.
Was done with a home-made collapsable wooden tube former.
Haven't a clue where to begin looking, but some time on Google should get you there eventually.
I'll do a quick search.

Edit: Strange... a google image search for "homemade fibreglass ota" brings up pages full of photo's of Zimbabwean politicians!

No joy with a quick search, maybe someone else remembers the site and can provide a link?

[Astro78]

Hi Gary,

The key i've found is looking for 'polymer' companies. It's not cheap though.

parksoptical.com do them cheaper in the US and protostar use some interesting material. I'm considering their tube for the 10"

[Suzy_A]

I bought some from this mob in Perth - http://www.fibreglass-resin-sales.com.au/home.html They also have some useful info on their website.

It cost me about $350 to make a 10" tube - actually the tube is about 12" diameter by about 1.2 m long.

I made a two-piece mould using a piece of 12" PVC tube and normal fibreglass and resin, then the actual tube out of carbon and resin. I vacuum-bagged it to get a nice finish and get rid of the excess resin.

The tube weighs about 3 1/2 kilos or so and is single layer woven mat but double layer at the ends for about 200 mm to provide extra stiffness and support for the mirror cell, spider and focusser.

[Astro78]

Do you have any pics on how it turned out Suzy?

Sounds easily less than half the price of getting it made professionally.

[davewaldo]

You might also like to try Pacific Composites. They seem to have good prices for the matt.

:)

[MrB]

I've also bought through them for non-astro projects, great people and huge range of glass/carbon in different weave/weight combo's.
The elderly woman there(don't recall her name) has an amazing encyclopedic knowledge, sure knows her stuff!

[Ian Robinson]

I couldn't anyone in December except a local boat repairor who quoted me an outrageous amount to make a tube from carbon fibre ($400), thought about importing a ready made tube from the UK (Orion Optical) or USA (Protostar) but the shipping was prohibitive (the volumetric mass is murder), then looked at rolling a tube from aluminium sheet 2mm thick ($250), and was given an offcut of PVC stormwater pipe (306mm ID) by a friendly subcontractor and that solved my new tube requirement problem so I can upgrade from my old Formatube.

[CoombellKid]

Kill the tube and go with truss :thumbsup: about $30 in ali :)

regards,CS

[Suzy_A]

I once made a large (24") diameter tube for a 20" newtonian. I used cardboard tubing (about 10 mm thick) on which I put on the ouitside a single layer of fibreglass matt and resin. On the inside, I also put a layer at each ends but only for about 200 mm up the tube. The rest of the inside I just varnished with epoxy resin and then painted matt-black. I didn't vacuum bag it or anything like that.

To finish the outside, I coated it with two coats of white-gellcoat. For the first coat, I used a roller and this gave it a sort of stippled finish. I then sanded it and gave a second coat with lots of styrene wax in it which gave it a very smooth (but still stippled) and tough surface.

This tube was very stiff and there was no need for carbon or kevlar.

For my 10", I wanted to do the same (but with carbon fibre and vacuum bag it to make it lighter) but I couldn't find any 12" cardboard tubing - the place that I got the 24" had closed down and I was unable to find anywhere else in Perth that sold large diameter light-weight cardboard tube.

So as a result, I made a mould using PVC stormwater pipe and then used the mould to make a tube with a smooth ouside.

It took a long time and a lot of extra cost - first sand and polish the PVC, then make a two-piece mould, polish that, then the tube.