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Flocking a 5" F/5 reflector (aka polishing a *BLEEP*)

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#1 SteveTheSwede

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Posted 10 January 2013 - 07:26 PM

First, let me tell you what this post isn't: it is not a how-to for flocking scopes by an expert.
Rather it is a documentation of my first attempt at flocking (and for that matter first attempt at any scope modification). I thought it would be worth posting anyway, in case someone can extract something useful from my endevour.

I decided to try my hand at flocking this scope precisely because it is a cheap one. Some might argue it's a waste of time to mod an entry-level Chinese newton, and perhaps they'd be right, but my main purpose was to get some experience in modding scopes. With this instrument it wouldn't matter too much in case I, well, flocked up.

This scope has been standing unused for the past three years, me relying on binocs, the astronomy club scopes and friends' scopes in the meantime. New scopes are forthcoming so I thought my little newt would be a good candidate for some tinkering. The mirror was also a bit dusty so I decided to clean it while I was at it (something else i have not attempted before). The only thing I have done to this scope in the past is to take apart the focuser and the EQ-2 mount, remove the glue-like substance passing for grease, sandpapering off the rough edges (of which there were many) and applying some good grease. On a side note the effect on the EQ-2 mount was dramatic, huge improvement, it went from barely usable to fairly smooth. But I digress.

While I consider myself reasonably handy, I am not a mechanic or engineer. Nor do I have a personal machine shop. This project was done literally on my kitchen table and with simple tools (a couple of screwdrivers, a box-cutter and scissors). The whole thing took one afternoon, with breaks for walking the dog and making food.

The flocking material I used is a black cotton velvet that my wife bought for me in a fabric store. The clerk said it was used by studios and theatres for sucking up light and killing reflections, which sounded perfect. I have no idea how it compares to specialized scope flocking material, but it seemed right to me. I decided to use double sided tape instead of glue and got a 3M product intended for carpets. It was thin and specifically for fabric so I figured it would do nicely. The cost for the fabric was 15 Euro for on square meter and 12 Euro for the tape. The total cost of this project therefore landed on 27 Euro (about 35 USD).

I used less than half of the fabric. Before and after application I rolled it with a lint roller to remove dust and fluff. I also took my wife's suggestion to iron the fabric before application. I did not follow any specific instruction when doing this. I just read up on flocking (here and elsewhere) and then tried to apply common sense.

Ok, let's get on with stuff. The scope in question is a Sky-Watcher 130 F/5 reflector.

EDIT: holy manure, I can't believe how sensitive the naughty words-filter is :D Well you will get what is being polished, I'm sure.

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#2 SteveTheSwede

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Posted 10 January 2013 - 07:26 PM

Scope taken apart with the flocking material and tape in the foreground.

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#3 SteveTheSwede

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Posted 10 January 2013 - 07:29 PM

First strip of tape applied. I decided to leave a little space between the strips, in retrospect I could have taped the whole tube but this worked. I didn't use any measures or tools to get everything perfectly straight but I tried to make sure the tape was flat and smooth.

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#4 SteveTheSwede

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Posted 10 January 2013 - 07:30 PM

More strips going in...

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#5 SteveTheSwede

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Posted 10 January 2013 - 07:32 PM

Flocking material going in, I just rolled it up and applied it in one piece. The first and last bit was the trickiest but it was easier than I had expected to keep it smooth.

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#6 SteveTheSwede

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Posted 10 January 2013 - 07:34 PM

All of the material is in but not yet cut to size at the tube ends.

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#7 SteveTheSwede

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Posted 10 January 2013 - 07:36 PM

After cutting up the velvet for the focuser I simply super-glued it to the tube on the outside. Not pretty but the focuser will cover the mess.

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#8 SteveTheSwede

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Posted 10 January 2013 - 07:38 PM

Cleaning the mirror in the sink. I followed the instructions in this video How to Clean Your Telescope Mirror and it worked just as advertised.

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#9 SteveTheSwede

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Posted 10 January 2013 - 07:40 PM

Scope put together again. Getting the material under, around and inside all the edges and things took more time than I expected, perhaps two hours, but I thought it turned out rather well.

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#10 SteveTheSwede

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Posted 10 January 2013 - 07:41 PM

I didn't get any folds or wrinkles anywhere in the tube, completely smooth all around.

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#11 SteveTheSwede

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Posted 10 January 2013 - 07:44 PM

Done.
I'll do the collimating tomorrow (hoping that I didn't somehow mess things up with the mirrors when I reassembled). I can't do any testing tonight anyway due to overcast skies, snow and high winds.
Assuming things will collimate fine I am rather satisfied with the result of the flocking. I'll come back with a totally subjective report on any detectable improvement as soon as I get a chance to observe.

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#12 Ed D

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Posted 10 January 2013 - 07:52 PM

The picture of your mirror in the sink is simply awesome!

Ed D

#13 SteveTheSwede

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Posted 10 January 2013 - 07:53 PM

Thanks and I also thought it turned out nice. That was the scariest part of the whole thing, taking the picture one-handed while not dropping the mirror :)

#14 Tom and Beth

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Posted 10 January 2013 - 07:54 PM

I also did my tube, but then as my pic shows, the inside of my Hastings Irragation tube was SHINEY.

It's been over 5 years The effect on contrast was much more pronounced than putting polish on *bleep*

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#15 The bear

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Posted 10 January 2013 - 07:58 PM

looks like it worked very well and thanks for sharing.
doc

#16 GlennLeDrew

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Posted 10 January 2013 - 10:02 PM

One thing which should noticeably improve things further is a tube extension on the front--flocked, naturally.

#17 SteveTheSwede

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Posted 11 January 2013 - 05:12 AM

Oh right, good idea, thanks. I should've thought of that. I've got plenty of flocking material left so no problem.

EDIT: Do you (or anyone) have a suggestion to what material to make an extension tube from? Cardboard probably isn't a good idea if it dews up and get wet.

#18 hottr6

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Posted 11 January 2013 - 08:33 AM

The picture of your mirror in the sink is simply awesome!

+1 :waytogo: All of Steve's photos are excellent.

#19 SteveTheSwede

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Posted 11 January 2013 - 08:46 AM

Thanks!

Ok, collimation done. The secondary was unsurprisingly out of wack, but the primary mirror was much to my surprise spot on. I expected it to be way off since I removed it to clean it. Anyway, I didn't ruin the scope it seems. Now one would wish for clear skies but the solid grey cloud-cover tells a different story, as does the weather reports :(






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