Black or White? - Page 2

Photon · #21 20-01-2006, 09:55 AM

Hey Dave,
Interesting Rajah's comments. Maybe if we go "White" we may not have to use the hairdryer again!! Boy that last meet was a 'wet' one.
IanG

Suzy_A · #22 20-01-2006, 12:45 PM

Quote:

Originally Posted by ballaratdragons

Not much help are we

No, but mildly amusing...

ving (David) · #23 20-01-2006, 01:38 PM

glad to be of sevice m'am

made up your mind yet?

Suzy_A · #24 20-01-2006, 02:12 PM

Quote:

Originally Posted by ving

glad to be of sevice m'am

made up your mind yet?

Maybe chequered?

Or hot pink?

Actually, still undecided. On Monday I'll go to the place that sells fibreglass, carbon fibre, polyester and epoxy resin, gelcoat etc and ask them about the practical aspects of making the tube.

The main problem that I see is actually constructing the tube.

The mould is no problem - a two piece mould - ( and ) - if you know what I mean, with the smooth side on the inside of the mould. Basically just sand, polish and prepare the PVC tube outside and then make a two-piece mould around it using fibreglass.

Then make the actual tube - and this is the hard part.

Either I can join the two parts of the mould together () and try and use a single piece of carbon fibre wrapped around the inside of it. I can see that this may be difficult and a bit messy, but will give a one-piece seamless tube. If I first use a layer of clear resin or gelcoat, then the carbon fibre, then the epoxy or polyester resin, then it will look nice and shiny and black. Or I could use white gelcoat, then carbon, then resin, for a seamless white tube.

The other way would be to make the two halves and then join them later. This would be much easier to do but if it is only clear resin and the carbon, then there will be two obvious joins. Using white gelcoat, carbon and resin would mean that the join would be invisible.

iceman (Mike) · #25 20-01-2006, 02:27 PM

You should talk to forum member "Bird". He got his own tube made out of aluminium, and there was a thread a while back about it and how it is much better in resisting dew.

It looks great too, nice and shiny.

iceman (Mike) · #26 20-01-2006, 02:27 PM

Here's one of the threads about it. some interesting reading.

http://www.iceinspace.com.au/forum/s...=dew+aluminium

stinky · #27 20-01-2006, 03:40 PM

As for colour and bumping the tube - on sailing boats it's an old trick to paint deck fittings black so that they stand out at night (obviously the deck could not be black!). Visibility in low light is a question of contrast - black to any other colour in low light is as extreme as it gets.

ving (David) · #28 20-01-2006, 04:47 PM

thats brilliant sco.... i mean guest!
have your tube black and the area surrounding the telescope a brighter colour so it stands..... hang on, do you have an ovservatory?

RAJAH235 · #29 20-01-2006, 06:46 PM

Do you really need to go to all that trouble to mould a tube? Why not use 'Sonotube' like Meade do. Cardboard concrete/pillar moulding type tube. Lots of sizes.

L.
ps. If you paint it white, you'll have less prob with dew as well.

pps. Good thermal Q's 2.

fringe_dweller · #30 20-01-2006, 07:20 PM

Quote:

Originally Posted by RAJAH235

ps. If you paint it white, you'll have less prob with dew as well.

pps. Good thermal Q's 2.

pssst ...over here ... paint it black..dont tell rajah ;-))

Suzy_A · #31 20-01-2006, 07:23 PM

Quote:

Originally Posted by RAJAH235

Do you really need to go to all that trouble to mould a tube? Why not use 'Sonotube' like Meade do. Cardboard concrete/pillar moulding type tube. Lots of sizes.

L.
ps. If you paint it white, you'll have less prob with dew as well.

pps. Good thermal Q's 2.

Sonotube is unavailable in Perth.

Large diameter cardboard tubing use to be available in Perth but not anymore. I once bought some large diameter plain tubing (not coated) and fibreglassed it and it was perfect! But the place that made it was bought by a multi-national and then closed down.

The largest size of 'formatube' now available in WA is 250 mm diameter. A few places offered to get some 300 mm for me, but the cost of shipping was unreasonable - it works out only a bit more to buy the PVC tubing, make a fibreglass mould and then a carbon fibre tube.

Not only that, I think that using carbon fibre/epoxy only, I can make a tube that weighs only 2 - 3 kg, as against about 7 for sono/carbon/epoxy, or 11 for PVC. The other option is 1 mm aluminium as that would only weigh about 3 - 4 kg.

stinky · #32 20-01-2006, 07:27 PM

Quote:

Originally Posted by ving

thats brilliant sco.... i mean guest!
have your tube black and the area surrounding the telescope a brighter colour so it stands..... hang on, do you have an ovservatory?

..don't paint the walls black - it's not cool anymore.

But seriously if there is ANY light at all black stands out.