Flocking

[xmal]

Simple question- what is it?? I have heard it being mentioned numerous times in threads. I would appreciate it if someone could answer me

Cheers,

xmal

[Astro_Baby]

Its basically a material or treatment to make the inside of the telescope tube as non-reflective as possible....

it can be done by adding woodchips to flat black paint and various other methods but its most comonly done with a kind of sticky back felt. The most well know is Protostar which is designed to not shed its fibres (cos you dont want black flecks of fibre all over optical bits).

Heres a pic of my own scope with flocking in - its been over-flashed so the flocking material shows up but under nrmal light its a completely non refelective surface and looks like your looking into a black hole. The left pic is with lots of flash - the right as it appears (kind of) to the eye.

[xmal]

Astro_Baby did you mod the flocking or is that photo stock? Looks very dark compared with mine....

[Gadget]

I often wondered what the meaning of that was when I see a telescope being sold as being "flocked"

Might be a silly question is there a reason why manufactures don't make the inside of an OTA to be as non-reflective as possible if it does make that much difference to performance

Kev

[xmal]

I often wondered what the meaning of that was when I see a telescope being sold as being "flocked"

Might be a silly question is there a reason why manufactures don't make the inside of an OTA to be as non-reflective as possible if it does make that much difference to performance

Kev

That is exactly where I am coming from. If it makes a big difference one would think all scopes would become hi-grade "flocked".

[Astro_Baby]

Yes thats my tube after applying Protostar flocking. Its kind of a fine fuzzy felt and once its applied the inside of the tube is totally non-reflective.

Does it make a difference to views ? I cant give you an honest answer based on experience. After I flocked my tube we had clouds for about 4 months straight and by the time I got to use the scope again it was impossible to say. Some people say it makes no difference others say it does. It makes the scope look cool though And for me it covered up the nasty hole in the tube where the focusers were changed over so made the inside of the scope look nicer.

Manufacturers usually apply a spray paint finish which is cheap and less bother. Although stuff like Protostar isnst tough to apply it is time consuming.

Some manufactureres of premium scopes do in fact apply either flocking or something a bit more complex like baffling - which is a series of ridges down the scopes body to knock out any reflections. This isn't as usual on Newtonian scopes as it is on refractors but some high spec scopes or scopes geared for astro imaging do have it.

Its hard to photograph protostar and show much of a difference really - taking pics of things that are black and then a pic of something thats even blacker is quite tough

[TopHouse]

Flocking nice job Melanie!

To the OP, here's a thread where I did mine with some pics etc, to me it certainly made a difference, not only were features of the moon a lot more defined but I also got more detail on Saturn after flocking.

http://stargazerslounge.com/astro-lounge/99648-project-stealth.html

[red dwalf]

have a word with "johninderby" if you want to flock your scope, he sells it,

i did my skywatcher 130p with it and i`m sure that the contrast was better with it flocked, very sticky stuff but easy to do and it looks great as well

[Astro_Baby]

Well there you go - it does work

[Arushin]

I agree,

definate improvement after flocking my 12" lLightbridge.

Noticable difference in contrast, although it wasn't easy felting the truss tubes. With a shroud I now have a totally black tube inner.

I have no idea why Meade left so much shiny white surface inside the Lightbridge tube on all but the 16". I would hope they have sorted it now as I have had mine about 3 years.

[Rusty Strings]

Flocked my 200p and also painted any bolts/nuts and the edge of the secondary matt black, did it make a difference? I had the same problem as Astro baby, unremitting cloud, so I can't say for certain, anyway it was a good excuse to take it apart and work out how it went back together.

[Glider]

I recently flocked my 200P and have to say it has improved contrast on the moon which is all I've seen since I did it. I also painted the back and sides of the secondary and focuser barrel like Rusty.

I bought 2 sheets from johninderby like red dwalf. At first I just flocked the secondary end of the tube because I had read threads where people thought that this was what really made a difference. However, when I looked down the tube the difference in reflection from the flocked and unflocked tube made me do the whole lot. It was like someone sitting down the bottom of the tube shining a torch up at me. The black painted wall was clearly far more reflective than the flocking.

If you are going to do it my experience was;

...Strip the reflector down to just the tube.

...Trim the flocking sheets to be 'square'.

...Cut and apply 3" wide strips at a time.

...Start at the seam in the tube.

...Finish 'on' the seam with no overlap onto the first strip of flocking.

I found that the flocking stuck instantly to the metal tube but kept peeling from itself where it overlapped.

I guess you could add extra glue of some sort to the overlap but I didn't.

Flock over screw holes and focuser hole, cut them out later with a sharp knife. Stop about 1" short at the primary end so you can get the mirror assembly back on. Have about 1/2" overlap at the secondary end of the tube, trim with a sharp knife and fit the tube end trim back on.

Took about 2 hours. Enjoy.

[Coco]

Probably worth it on a Newtonian but not on a well baffled Frac

[Rob]

I've heard of others using extra glue in the form of spray on carpet tile glue. Is that required?

Rob

[Astro_Baby]

Coco I dont think you could do a frac really - the tubes pretty narrow and all the baffles would make it a nightmare to install.

Even on a 4.5" TAL 1 its near on impossible to flock because of the narrowness of the tube. If you had to deal with baffling I think it would be a non starter although some people flock just the between the firts and last baffle.

[xmal]

Back to basics. What is flocking? A paint? A stick on veneer? Sorry for the basic question...

[Glider]

It's like a sticky back felt sheet.

I bought some carpet spray to try on the overlap but the problem was it doesn't ever seem to 'go off' and stick the sticky back to the felt. Hence my solution of stopping on the tube seam.

[Astro_Baby]

Ahhh well its a generic term really though most people will think of it as ptofessional flocking paper.

It can be almost anything really such as;

Flat black paint mixed with woodchips

Thin polysyrene foam painted flat black (also acts as a thermal insulator)

Felt (most common - Professional flocking paper is a kind opf soft felt type material)

I cant think of other stuff though there are probably other ways of doing it - Hessian cloth I suppose could do it.

In a nutshell when most people talk about flocking they are talking about a felt like material.

[TopHouse]

Extra Glue & Seams

No extra glue is needed for actually sticking the flock, however it doesn't overlap well at all, what I did was this. On the overlaps it does stick temporarily, so, after flattening it down I ran a line of medium thickness cyanoacrylate down all my joints, it has never come unstuck.

[Glider]

TopHouse, cyanoacrylate. I'll give that a go, you are right, the flocking on the tube needs no extra glue, the sticky back is very good, it's just the areas where the flocking overlaps on itself.

I had tried various sprays, wood glues, epoxies, etc on offcuts but they all came apart or left big white stains on the nice black velvet.

Thanks.

[acey]

"Flocking" is one aspect of "baffling", and an excellent article on the subject (which could save you time and money) is this:

http://www.urania.be/forum/download.php?f=1&file=baffling.pdf

Basic aim: eliminate stray light reaching the eyepiece (i.e. for Newtonians, anything not coming from the secondary).

Basic strategy: look through the focusser and see where the stray light is coming from. Flock, paint or shield those parts. (The worst offender may turn out to be the interior of the focusser drawtube itself; another problem area may be the edge of the secondary).

I did it on my Flextube (for which I needed just one sheet of Protostar) and it definitely made a difference:

http://stargazerslounge.com/equipment-discussion/99482-improving-flextube-contrast.html

Just remember the golden rule: what counts is the view through the focusser, not the view looking down the front of the tube. Stray light bouncing back into space is not a problem.