Flocking

[iceman]

Hey guys.

Next project on my 10" dob is flocking the inside of the OTA. I want to clean the mirror next week, and so I figured I may as well flock the tube at the same time.

I looked for some adhesive black velvet, but neither Bunnings, Mitre 10 or any paint/wallpaper shop had any.

I ended up buying some black plush anti-pill stuff, it's a few mm thick, but it won't obstruct the light path, it looks like there's about 10mm each side of the OTA to where the mirror is.

Anyway this stuff looks nice and anti-reflective, but of course it's not self-adhesive. What do you recommend I use as an adhesive? It needs to stick material onto the aluminium tube.. i'm sure there's some sort of contact cement/adhesive that would do the job?

Any advice as to the flocking itself?

I've read recommendations to do the length of the tube in strips.. How many strips? (how wide each strip)
Do the length in one strip, or half the length, and tackle each lengthways half separately from opposite ends?
How much glue?
Overlap or not overlap?

Also is it definitely worth doing the whole tube rather than just around the mirror and opposite the focuser?

I figure I also need to paint flat black on the shiny bits inside the tube, especially the shiny new screws for the moonlite, and perhaps the mirror cell as well?

Oh and the secondary mirror - I assume I need to take out the spider and 2nd mirror.. is it just the 4 screws holding the spider in? Do I remove the secondary first and then the spider veins?

Advice and suggestions appreciated!

[Orion]

Ice I did the inside of the mirror cage with velvet I used contact cement (the yellow stuff) and applied it to both surfaces let them touch dry before you bring both surfaces together and they will stick immediately.
I didn’t use strips I just cut enough to do the whole job but I did a section at a time. Roll the telecope as you go. Rub your hand over the felt making sure you get no creases.
It is time consuming but it is well worth it I believe and it looks great.

[Starkler]

The biggest gain from flocking is to do areas that are visible from looking into the focuser. ie the area directly opposite the focuser and the bottom of the OTA immediately above the primary.

If light cant get to the focal plane with one reflection off the tube wall then its not nearly so important as the two areas I suggested.

[ballaratdragons]

An alternative thats works! And it's easier too.

Black Flock can be purchased in a powdery form from good craft shops.

Spray the inside of the tube with Spray adhesive, throw the flock substance in, turn the tube around and around, shaking, tapping,
until the total interior surface is covered in flock.

Let let glue totally dry and lightly air blow or lightly vacuum out the loose particles. Hey Presto! Job done!

[iceman]

Thanks for the help guys - so starkler you suggest just doing those 2 areas?

Is taking the secondary + spider out an easy enough thing to do?

I got enough of the material to do the whole tube, but just wonder if it's worth doing all of it or just the areas you suggested.

Thanks

[gbeal]

Mike,
do the whole tube. I use black felt, and bought it from a fabric supplier/drapery type place, in a roll a metre wide. The spary on idea that Ken suggests sounds good as well though.
In my cases I divide the tube into segments, with a spacer/light baffle at the join, and this spacer/baffle is effectively held insitu by the felt either side.
I have heard thought that baffles like this can be harmful to the tube currents.
Gary

[Dave47tuc]

Mike,
When I had my Newt, I used black board paint with a matt powder to do my tube inside!!!:P

Also If you make a extension for the front or your tube say 25 to 30 cm long. Say out of black poly or something like that, the same as a SCT dew sheild this will help greatly.:D

Good luck with it all.

Best.


:astron:

[Starkler]

This topic just came up on a yahoo group.

http://groups.yahoo.com/group/skyquest-telescopes/message/28774

But if you want to flock the whole tube it will look prettier :)

[iceman]

Thanks Geoff, sounds like there's consensus.. i'll do the whole tube, may as well do it all when the mirrors are out.