Is pond liner completely opaque?

[darthvader]

I dont have an observatory as such, I use a garden summer house to observe from most of the time (my long term plan is to somehow convert it into an obsy)

However, the summer house (basically just a big shed with windows) has three windows and double French doors (telescope normally points out of the French doors when observing) that are currently covered with thin material that was in place when I bought the house.

I have been researching different options to cover the windows (and doors) for the cheapest price and have come to the conclusion that pond liner may be the way to go, For the following reasons:

Cheap - I can get 4m x 4m sheet for around £25

Flexible - easy to cut, handle and fix to window frames (probably with staple gun or drawing pins or similar)

Easily removed - if I ever want to revert use back to summer house!

I have ruled out Black out material, hardwood, plywood and painting the glass for reasons such as price, ease of application, poor light blocking capabilities etc.

My questions are:

1. Has anyone used pond liner for this purpose? If so is it completely opaque?

2. If not, does anyone have a bit of pond liner lying around they could test for me

[NickK]

I think it depends on the type of liner.

I do have a pond and it's pretty dark but there's different liners - rubber based etc. However I've never looked through it at the sun lol.

[Mukv]

Greetings

I have a few meters laying in my shed, it is 1.2mm thick and no light passes through even using quite a powerful dive torch point blank and it would make a good choice for light blocking.

Andy

[tekkydave]

Try rubble sacks. They are basically very thick bin liners. I haven't tested them but might be cheaper than pond liner.

[darthvader]

Greetings

I have a few meters laying in my shed, it is 1.2mm thick and no light passes through even using quite a powerful dive torch point blank and it would make a good choice for light blocking.

Andy

Awesome, thanks for that

Try rubble sacks. They are basically very thick bin liners. I haven't tested them but might be cheaper than pond liner.

That's a great idea I do actually have a few of them - I could probably use them on the windows but they might be a little small for the doors without joining together( even opened up) but definitely worth a try before I buy some pond liner.

[Stargazer33]

Our pond liner is quite thick and no light could possibly pass through it. One thing to consider is that pond liners tend to break down in sunlight; they go brittle. Through glass this degredation may be accelerated. As long as nothing pushes/leans against it though, it should be okay and sounds like a good solution.

[darthvader]

Our pond liner is quite thick and no light could possibly pass through it. One thing to consider is that pond liners tend to break down in sunlight; they go brittle. Through glass this degredation may be accelerated. As long as nothing pushes/leans against it though, it should be okay and sounds like a good solution.

Hopefully will only need it for a couple of years until I convert the summerhouse into a more permanent obsy

[Dave_D]

i used a piece of thick black pond liner to make a screen to block out a local street light. worked a treat

[darthvader]

i used a piece of thick black pond liner to make a screen to block out a local street light. worked a treat

That's good to hear -I've ordered some now so I'll report back when it arrives

[darthvader]

Arrived yesterday, fixed to two of the windows to test and it works perfectly! No light at all passes through it

I attached it with drawing pins which means I can remove it easily if required and I've got loads left over from the 4m x4m pack to make a screen for the garden like Dave_d . Mind you it did cloud over shortly after I fixed it..... How on earth did the astro gods know it was for astronomy purposes - I thought I'd fooled them by buying a garden pond product! !

[NickK]

you may need it's waterproof qualities at this rate..