Flocking

[iceman]

I've flocked bits and pieces of the inside of my OTA (opposite the focuser and down around the mirror), but I used a fairly thick felt and some adhesive that didn't really work very well.

So the end result, is a pretty messy job (though it still works ok). I want to clean it up and do the whole tube.

After seeing Dave47Tuc's excellent flocking job at Snake Valley, this thread is specifically for him, to tell me:

a) What material he used
b) What adhesive he used
c) How much they were
b) Where he bought them from

So Dave, take it away :)

Looking into his tube, there was zero light reflection and it looked great.

[xrekcor]

Yes Dave! I'm all ears too. Was this on a GSO dob Mike? as I think my 8" would benifit
from some flocking.

regards,CS

[iceman]

Yes Rob, it was on the 10" GSO Dob. It would benefit all sizes of GSO dobs (8-12") and of course non-GSO dobs too :)

Ken's 12" was painted Matt black on the inside, but it still was more reflective than the zero reflection in Dave's tube.

[dhumpie]

Mike you need to get those adhesive backed felt from Bunning's or Mitre 10. They used to have some pretty good stuff but lately I have not been able to find them (maybe someone else might know where to find these). I got some Protostar flock paper from the states and they are a shocker. They don't stick down very well when overlapped so my flock is quite messy as well. But I like to think of the wrinkles as offering additional baffling :)

Darren

[davidpretorius]

cmon Mr Tuc47, i listening as well!

[5ash]

If you go to one of the big art supply shops you can get black flock paper. It is really inky black when stuck inside an optical tube . I used it once inside the focusser and eyepiece barrels of a 6 inch refractor.I used double sided tape to secure it .
philip

[Starkler]

Took me about 2 minutes to find the answer with the search function.

http://www.iceinspace.com.au/forum/showpost.php?p=26455&postcount=3



THe flocking I used is noticably darker than Daves, but being a vinyl based product with some stretch in it had caused it to let go in some placed :(
I got mine from Bunnings but its no longer available .

[Dennis]

Hi

I found this link http://tinyurl.com/bzbv7 in a discussion in the C9.25 Yahoo Groups. It points to a flocking thread on sci.astro.amateur in which luminaries such as Roland Christen (Astro-Physics) made comments. Well worth a read (if the link still works!).

Cheers

Dennis

PS - to whet your appetite, here is an excerpt from that thread which spawned some quite interesting discussions.

Start copy+++++++++++++++++
"Flocking doesn't change the sharpness of the optics, does not eliminate
any optical aberrations, does not smooth out rough surface finish, does not
reduce the central obstruction, etc. These are the primary things that affect
planetary contrast. Flocking does affect the ability to see faint deep sky
objects in light polluted skies, but again does not help any in really dark
skies. Planets are so bright with respect to the background sky, that it makes
virtually no difference if baffles are there or not. The light from the planet
is blocked from coming directly into the eyepiece by the secondary mirror, and any light that does come in on the side from the background sky does not have enough brightness to register with respect to the planet itself."
End copy+++++++++++++++++++

[xelasnave]

Gee I dont know that flocking does not help in really dark sky. I "invented" a long dew tube with 8 baffles (2.5 feet) in an effort to reduce stray star light entering the tube for my 150ar and it made a noticable difference in my dark sky. The tube inside in not flocked yet (cant find the stuff locally) but I recon that will improve things more.
alex

[Dave47tuc]

Hello, hello calling Dave!! Yes I'm here. :lol:

Everybody has an opinion on flocking. Mike has seen my scope and as I say the proof is in the cooking. :lol:

I say it works for me and thats all that matters to me.

So Mike, I got my flocking material locally from Mitre 10. It seems the stuff is not in all stores nor at Bunnings anymore. :confuse3:

On the backing sheet(I still have some) it has a Logo "alkor" Deco Design.
Dem Trend voraus. :help3: It is self adhesive.

It cost me about $14 per Metre.

Hope that helps Mike and you can Pm me is you want more details. :)

[iceman]

Thanks Dave. How many metres did you need to cover the inside of your OTA?

[bird]

All those points are correct, but they left out the most important one! (well for high res imaging, is there anything else? ;) ) Flocking isolates the air from your tube so that "supercooling" of the metal tube under the night sky won't cause waterfalls of cold air to start running down inside your scope and across the mirror.

It also (slightly) reduces the ability of the air inside the tube to lose heat as it's no longer in direct contact with the metal, but for people with open ended tubes this isn't a problem anyway.

I'm very happy with the results on my tube, I bought adhesive black felt from one of the craft stores, but in hindsight the mitre10/bunnings idea sounds like the better one. Felt does shed a little when you first put it in the tube, but that stops after w hile when all the loose fibres have come out.

Bird

[Dave47tuc]

Gee I can't remember exact :doh: I think 2.5 metres did the job. I got 4 metres but have over 1 metre left over.
Good luck with it.

[xrekcor]

I'm not certain, but you could try Bunnings in Lismore. Prolly the nearest for
you/us next time I'm over there I'll be dropping in to have a look. Not sure
when that will be, haven't been there for a few months lol

regards,CS

[xrekcor]

Hmmm just read Dave47tuc's post, there is a Mitre 10 in Casino, albeit a lil expensive one. Bunning in Lismore is absolutely huge!

regards,CS... nope looking like lightening : (.............

[Loupy31]

Hi Guys, I found that "spotlight" has it in rolls of 1 mtr wide and any length you need, and with a VERY sticky adhesive backing, So you had better make sure you place it where you want it to be.


Peter

[Thiink]

I was thinking about flocking the inside of my OTA this weekend to give me something to do (yer, like I dont have enough already :P). Where did you end up getting your felt from Ice? Do the different flocking materials people use differ in any major way? I havent seen any so Im guessing its just thin felt with a sticky back? Id rather not use spray on adhesive as its shocking stuff to work with.

John: did you find out what Spotlight call their product? If I know in advance it will save me sounding like a dork trying to explain myself.

[iceman]

I bought some new material about 3-4 weeks ago.. haven't redone the inside of my scope yet, but still plan to.

I got some self-adhesive black suede/felt from Mitre 10. I bought 3 metres of it I think, costs about $20/metre. Looks like great stuff.

And will be much easier to install without worrying about contact cement.

[ving]

how bout the stuff you put on the outside near your focuser mike? would that work well?

[iceman]

Yep that would work too.. that's 1 sheet of stuff I bought from Lincraft a few months ago as a test, it's more of a felty material whereas the new roll I bought is a suedey material.

They're both almost exactly the same cost.. the lincraft one comes in squares, the mitre10 one came in a roll.

[iceman]

btw here's a photo of that black felt around the focuser.

[ving]

the lindcraft one is avaliable in spotlight as a roll :)
of course this doenst help you, cause you have already bought your suedey material :P

[Thiink]

I just tried Mitre10 Bathurst and Orange and neither have the part number that Dave listed. :(

edit: hm I just went for a walk down to Spotlight and they only have the 25x30cm squares for $2.50 each. Id need roughly 15 of them to do the length of the tube. and one more for around the focuser.. ouch!

[Roger Davis]

Something else about the black flocking you may wish to know is that it does not reflect IR. Tests done with a GenIII image intensifier and an infra-red source show no reflection whatsover.

[ving]

what does that translate to roger?

[ausastronomer]

Simon,

Thats exactly what I used to flock my tube over 4 years ago and its still working perfectly.

I also did a number of other baffling mods including 3 annular knife edge baffles one either side of the focuser and one just above the primary mirror. I also used 1/4" wide self adhesive foam weather stripping and baffled the inside of the focuser drawtube. You need to be careful when you do this that you get the foam in the right place and the also the right height so as to work properly but not vignette the light cone with long focal length eyepieces. You should also blacken the unsilvered bevelled edge of the secondary mirror with a black texta if you have a steady hand.

If you do all the mods properly the contrast will be improved enormously.

CS-John B

[Thiink]

Did you flock the whole tube with the squares John (I didnt get a chance to see your scope or accessoris case at Lostock.. I kicked myself afterwards!), or only the areas you mentioned? If you did the whole OTA, how did the squares fit into the tube? Did they overlap, or did you need some thin strips to get it all the way around. With my maths Im getting a tube cir. of 94.24cm, which is going to make things interesting (three and a bit squares around).

I only want to do the tube and a patch around the focuser like in Ice's pic at the moment.

[ausastronomer]

Simon,

I did the entire tube from 1" below the top of the primary right up under the retaining ring at the top of the scope. IMO its worthwhile doing the entire tube. I butted each square up to each other, then with the left over squares I cut strips 1" wide and covered all the joins with the 1" wide strips.

Have a look next time, its like the "Black Hole of Calcutta".

I actually have some pics of the scope showing the internal baffle rings and the focuser baffles which I will post over the weekend.

CS-John B

[Roger Davis]

Sorry about the delay in reply, been busy.
IR reflection is good to know about if you are doing CCD or DSLR photography.

[Thiink]

Yes its Thiink again on the flocking subject (I can hear the groans). After attempting to source some flocking material locally, Ive finally given up. I brought one felt square to try out from Spotlight, but because none of them were square, and the material didnt cut well, I have decided not to use it.

I have, however, found this company (http://www.fpi-protostar.com/) in the US which sells a few different flocking options. Im thinking about ordering some flocking material from them and found they also sell tube liners as well. Can you thermal gurus have a look at the tube liner (http://www.fpi-protostar.com/tubeliner.htm) and tell me if there would be any added benefit in it over flocking paper alone? The tube liners are also lined with a flocking material. If its not worth it I will just order some of the basic flocking material and put this flocking issue behind me. :)

ps. it got to 0.1c here last night, brrr!

[Vermin]

I've used the Prostar Hi-Tack flocking material to completely cover the inside of my 16" secondary cage and the mirror box. Installed as per the instructions (scored/cut every 2" or so) it continues to look perfect even after a number of hot/cold cycles. It's a bit difficult to see anything but black in this image but I'll post it anyway: http://www.iceinspace.com.au/forum/attachment.php?attachmentid=9941&d=1140919456

[astronut]

Hi Simon, I bought the black felt from spotlight, it's easy to cut as long as you use a sharp implement. You can also by it in rolls as long as you like, and half a metre wide;)