Using garbage bag material to make a shoud

[John K]

Hi guys,

I am wondering in anyone on IIS has ever used the thicker type garbage bags to make a telescope shroud.

As I need to make a new shroud for my 12.5" f/5 truss reflector, and constantly have to put the shroud on and off, thoughts that 2 x tie up garbage bags with their bottoms cut out and joined could be a low cost way of doing it giving a tie around mechanism as well on either end.

In terms of joining them together either a glue like Aqua seal which works a treat on synthetic material or even trying to iron the bags together at low heat with a domestic iron could work.

Look forward to thoughts.

John K.

[JA]

Hi John,

Perhaps a step up from garbage bags (not that there's anything wrong with that , ), you could try 14 inch /350mm spiral duct or one of these (unfortunately 18 inch) tunnels....

http://www.ebay.com.au/itm/Kids-Chil...QAAOSwOdpXzlTR

http://www.ebay.com.au/itm/5-9-Feet-...0zjgmfhZcdcfNQ

Of course it would be better in Black (paint or dye it? or look a for another) and it's a little large at 460mm, but perhaps you could upgrade to an 18inch

Best
JA

[glend (Glen)]

I made a shroud for my 10" f5 truss newt out of lycra, easily obtained on ebay. The problem with plastic is it will not breathe and thus condensation is likely to be a bigger problem, inside and out.
You could also look at thin neoprene, say 2mm, also available on ebay, also breathes. Neoprene is easier to sew than lycra imho.

[ZeroID (Brent)]

I used a black plastic bag for a while on the 10" F5 Serrurier in the early days (before Ob). Works ok as top and bottom were open so no moisture issues but I had concerns with the internal shiny black surface and possible random reflections.
It was also a nuisance to secure and could be noisy but when you're dealing with too much incoming scattered light as I was at the time it solved a lot of problems.

[NoTan2 (Paul)]

Originally Posted by glend

I made a shroud for my 10" f5 truss newt out of lycra.

How did you sew the lycra, Glen?

My wife tells me that her domestic sewing machine would not easily sew fabric like lycra.

I bought a commercial shroud - the one with the three vertical tubes - and have never used it (waste of $70). I find it too fiddly to fit and, because of the tubes, I can't leave it fitted all the time. Unusually for me, I didn't research it sufficiently and naively assumed that it was the same design as the Astrozap with the lateral ABS bands which can be left in place when the scope is collapsed.

I've been thinking of making one similar to the Astrozap but it might mean sewing it by hand.

[glend (Glen)]

Originally Posted by NoTan2

How did you sew the lycra, Glen?

My wife tells me that her domestic sewing machine would not easily sew fabric like lycra.

I bought a commercial shroud - the one with the three vertical tubes - and have never used it (waste of $70). I find it too fiddly to fit and, because of the tubes, I can't leave it fitted all the time. Unusually for me, I didn't research it sufficiently and naively assumed that it was the same design as the Astrozap with the lateral ABS bands which can be left in place when the scope is collapsed.

I've been thinking of making one similar to the Astrozap but it might mean sewing it by hand.

There is infornation online about sewing lycra. I did it myself with a cheap sewing machine i bought at a Salvo shop.
I used to have an Astrozap on my 16" dob but it suffered from droop into the light path. You can make your own stiffening bands out of ABS plastic. Just go online and buy a cheap electricians snake - used to feed cables through conduit or walls. You can join the ends with a piece of plastic tubing. Since they are naturally coiled the electricians snake makes a nuce round circle. Attach them to you struts or tubes using adhesive velcro.

[NoTan2 (Paul)]

Originally Posted by glend

There is infornation online about sewing lycra.

Thanks Glen. I found a youtube video showing how to pin "toilet paper" to the lycra and you can then sew it on any machine. I'll see what my wife thinks.

[mswhin63 (Malcolm)]

I made one for my 12" Skywatcher DOB many years back. It was from Lycra but I did not sew it,instead stapled it to wooden struts.

It worked a treat. I am trying to locate photos for it, although I still have it stored away somewhere. I will place it up when I locate the images

EDIT: I double layered the Lycra

[fbk (Fraser)]

I have a solid tube dob but nearly bought a SW flex. At the time I thought ahead about making a shroud for it, never did need to obviously but I was going to get a meter or so of 2mm neoprene and make a cylinder out of it. I think it would hold its cylindrical shape well, you could either stretch it over the focuser and tube, or put a velcro join in it.

[Wavytone]

Another material worth considering is a lightweight ripstop Dacron as used in spinnakers and paragliders, you can buy it from sailmakers and is easily sewn with a domestic sewing machine. Strong, doesn't stretch and available in black.

Best method is to make a hem along the edges with a Dyneema or Spectra string inside, this will give you neat edges that won't stretch.