WARNING: Flocking materials NOT stable over time!!!! Nightmare stuff!

[mental4astro]

OMG!

What a freaking dust bowl nightmare!

I've just looked into a Maksutov that was flocked a few years ago. And the inside of the OTA looks like a cat has been sleeping inside it!! :eyepop: :eyepop: :eyepop:

The flocking over the years has been degrading, and the damned fibers have been shedding from the flocking like snow in a blizzard!

The scope has been well looked after, but the flocking material has proven to be a ticking timebomb that has detonated in slow motion. . . . .

In the everyday handling of the scope (picking up, transport, set up, take down, variations in temp and humidity , etc), the freaking loose microfibers lift off the flocking material and contaminate freaking EVERYTHING inside the OTA!!! :eyepop: :eyepop: :eyepop:

I've always been unconvinced by the use of these flocking materials, especially knowing what they are made of, and I've always had a suspicion that they ARE NOT STABLE OVER TIME. And now that suspicion has been proven correct!

If you are thinking about flocking the inside of your scope, DON'T.

If you have already flocked your scope, BEWARE OF THE FLUFFY BOMB THAT IS ABOUT TO ERUPT!

And if you have fans inside your flocked scope, boy, you are in for a real FLUFFY treat!

Note also that NO scope manufacturers FLOCK the inside of their scopes! They know that stuff is a disaster.

And to clean out this mess will be a really crap job :(

Alex.

[FlashDrive]

Never done it myself, but thanks Alex.

Col....

[billdan]

Well I painted the inside of my 8inch newt with Matt black paint and after 5 years its all starting to flake off as well.

So I think either way flocking or paint it has to be re-done regularly.

[casstony]

I'm not sure flocking or baffles are needed at all on cassegrain style scopes since light can't reflect off the outer tube and reach the eyepiece. The central baffle is the critical element for preventing unwanted light reaching the eyepiece.

Matt black paint would do as well as anything else.

[ngcles]

Hi All,

One fabric I know works very well and stands the test of time is German 100% black cotton velvet. This is amazing stuff and when you spread it out on the floor it looks like a hole -- it swallows light. I have used it on several telescopes and it does not shed -- even after 15 years. Synthetic velvets look shiny by comparison. It is quite expensive and not easy to source either.

Don't expect to trip on down to the local Spotlight or some such place and pick it up my the roll. You'll have to source it from a specialist draper or on-line. You can stick it down on the tube interior with wall-paper paste, though I have also used an epoxy style glue in the past on my old 10" (that had a 12" id tube). For a tube like this, strip out the interior fixings and optics and then roll the velvet up on an old broom handle. Paint say, a 20% strip of the inside of the tube, put the broom handle with velvet attached down the tube, roll it out, smooth with hands, paint the next section with glue, roll it out, smooth with hands etc etc. Works very well though if you do use epoxy-style glue you may end up stoned (on the glue) by the end of the job (as I did) as you will spend a lot of time with your arm down the tube smoothing out and your head almost inside it.

Another (cheap and very effective) alternative is to crush up some peanut shells (or walnut) with a mallet or rolling pin into 2-3mm diameter fragments, coat the interior of the tube with glue and apply the nut-shell fragments very liberally, pat them down into the glue. Allow to dry and then paint this new (very rough) surface with two coats of matte black paint using a roller designed for stippled surfaces. If you buy a cheap roller handle you don't need afterwards, you can straighten it out to paint the interior of the tube more conveniently.

Trust me though, German cotton velvet is the duck's guts!

Best,

L.

[mental4astro]

The merits or otherwise of flocking or baffles in any scope is up to the individual person. What needs to be avoided IS FLOCKING in all scopes! These synthetic fiber materials are not stable, degrade over time, and shed their fibres over everything! These materials are a disaster for all scopes.

Now, again looking at scope manufacturers, NONE use flocking, but they do use baffles and good quality black matt paint, and use the appropriate primer if painting onto bare metal.

Les, that German material may be good, but no scope manufacturer is going to go with it. While that stuff may be good, there is no control over the glue used by people who stick the flocking to the inside of their scopes. The solvents in these glues are one of the major problems don't forget. It is more complex than just the flocking material unfortunately.

Alex.

[AG Hybrid]

You sure its flocking grade material lining the inside of your MAK or just craft shop black velvet?
So far I have flocked all my scopes with protostar flocking. Either the adhesive back and the flocking board.

That's the 12" newt, 4" refractor, 6" Mak-Cass.

My 12" has been flocked for at least 6 years now. Still performing like its new with nothing falling on my primary and you know what I've done with that work horse over the years. I used protostar flocking board though.
In fact I like it so much. I bought another flocking board piece for my new 8" f4 newt.

[mental4astro]

Good question Adrian.

What the stuff is neither I nor the scope's owner can say - was done by someone else, so also no idea what adhesive may or may not have been used. Nor if there has been any batch variations.

I have asked about some of the history of this scope, and the flocking was done at least 13 years ago. Untidy job too.

I am not saying flocking isn't effective - I've seen through your scopes too Adrian :) . But I also have seen synthetic materials degrade over time, glues, substrates, etc. If manufacturers won't touch the stuff, regardless of brand, and only go to the greater trouble of installing a large number of baffle rings inside OTAs, I can only also relay my experience and warn about these flocking materials. And if I'm am wrong about proprietary brands, then my warning needs to be made strongly directed towards NOT going cheap with flocking materials.

And Les, if it is the case of cheap vs the Real McCoy, then I welcome your sage advice and experience! :)

Alex.

[multiweb]

I've used the protostar material for a long time. The only issue is when it comes off the tube occasionaly but that can be glued back. I found that if you slice it into narrow strips with a razor blade after it has been laid then it won't come off when the tube is expanding or shrinking with the heat. Other than that I never had any issues with it degrading or peeling and I have stuff that's ~10 years old.

[AG Hybrid]

I reckon Alex.


Get some of the flocking board, naturally cut to measure for your maks tube, and put it over the top of the crap stuff. The boards tension will hold it in place and keep that crap that's peeling off from coming loose.


I think its better then trying to remove the stuff that's already on there.

Any thermal changes affecting the tube causing expansion or contraction wont really affect the flocking board or the flocking on the board.

[Steffen]

I've used Protostar FlockBoard in the past and would use it again without hesitation. It didn't shed, and hadn't changed at all after several years in service.

[LewisM]

Televue does. (their "special" paper flocking that detaches quite regularly - posts here on IIS and CN).

[tlgerdes]

I've got a Protostar'd Newt thanks to Marc A, and it's as good as when Marc laid it 8yrs ago, and I wouldnt say I've cared for it meticulously either.

[N1]

Hi Alex, could you elaborate on the exact damage that the loose stuff does - trying to determine whether it might be a non issue for my GSO dob (got some self adhesive velvety stuff on Aliexpress for this) - i.e. does it stick to, or contaminate/degrade any surfaces, or is it just some loose crap that will wash or vacuum off? If which case it wouldn't worry me too much...mirror gets washed every year or two, and the EPs are waterproof.

[Wavytone]

Mirko all fine and dandy in an open tube dob which probably benefits from being hosed out occasionally to get the dust out.

But closed - tube SCTs, Maks and refractors are another matter entirely where there is a considerable degree of precision involved in their assembly and they are not intended to be opened by the owner and doing so raises considerable risks of damage to the optics.

Secondly as Alex points out no manufacturer has ever flocked their OTA - not even Questar, TEC or AP - for good reason.

[Tropo-Bob]

I suppose this all goes under the heading: It seemed like a good idea at the time.

Not this one, but I have had a few like that! :(

[mental4astro]

Mirko, the "damage " involved is thousands upon thousands of tiny little fine short fibers plastered all over the optics and continuously raining down from the flocking material. What it does is not only dirty the optics & screw up contrast due to the significant amount of scattering these thousands of little fibres cause, but who knows what chemical damage these fibres will be doing to the reflective surfaces!!!! There's not just petrochemical but also the stuff from your hands left on the flocking material when it was installed.

The more I think about it, there is no way I would or could ever recommend any type of flocking of any scope. The risks are just too great, my scopes too precious, and no maker of these flocking materials will warranty their stuff against aging and degrading with time, and certainly NOT cover the cost of cleaning the optics or repairing any chemical damage their stuff causes.

Proprietary or not, I'm not going down the flocking route.

Alex.

[mental4astro]

I managed a few pictures of the fiber coated optics. Flaming EVERYWHERE these fibers, corrector plate, primary, secondary, and they will be all over the rear of the primary, inside and outside of the baffle tube, and it will affect contrast :( . Photos show the really dirty corrector (most of the dust is one the inside) and the fibers on the primary - tricky photo to take that of the primary's surface.

Alex.

[LewisM]

:lol: I’ll say it again - Televue flocks their refractors. Paper based at that

[DarkArts]

Note to self: don't use flocking paper/fabric. :thumbsup: Thanks, Alex.

At some point, though, if it keeps up, this thread is going to sound a bit like flocking a dead horse. :D

[LewisM]

You could use the glue from the horse to hold down the flocking

[gts055]

Alex, the flocked material used in your telescope must have been poorly made cheap material. I have two Televue refractors, both have the Televue installed original flocked fabric lining the tubes. The Pronto is 25 years old, the NP101 is 20 years old, with no issues whatsoever in either telescope. Mark

[Wavytone]

Methinks Alex is flocked ;)

[casstony]

I've only noted a few instances of problems with Televue flocking. Takahshi focusers though, my god..... it's a struggle to find a good one :)

[LewisM]

:lol: That’s only on American Taks where they have no clue how to adjust them or feel they must put a FT on them “just because”

Matt and I have been lucky I guess :P

[LewisM]

I believe TV will reapply new flocking free if it happens. Seems they had a bad batch or people used the scopes for solar.

I am fixing a Tak reflector now with major black paint loss internally. Just as bad if not worse than flocking when it fails

[Paul Haese]

Well I flocked my C14 in 2007 with spotlight adhesive felt for flocking. It's still in place and never once shed any lint. The scope resides outside under a Telegizmo cover all year round. Sorry to hear of someone else having this issue.

[N1]

Thanks Alex and Wavy, makes sense.




This has to be one of the best opening lines to a thread I've seen in a long time :P

[xelasnave]

Thank you Alex for your warning.
I have been thinking about flocking my eight inch rather than my old method of baffling paint and sawdust.
I have had a look at my six inch that I baffled and did the sawdust trick a decade ago and it shows no signs of failure.
Thanks again.
Alex

[Nikolas]

you make it sound so dirty :eyepop:

[Wavytone]

Hi Alex,

It has had me thinking for a while too.

I’m beginning to think a fair solution is to start with a sheet of stiff rag paper as used by artists - the kind with a rough surface and ideally in black - and paint this with Black 2.0 (from Stuart’ Semple’s website) and fit that neatly into the OTA.

This way it could be inserted into an OTA without the need to remove the optics and everything else bolted to the OTa (as with paint).

This way it can be easily removed or replaced later, if need be.

[xelasnave]

I think baffles are the go and I plan to use them to resist flex.
I may use resin and saw dudt as a base and that with sawdust should add strength one could think.
But hsving hsd the eight for a year and yet to do any adjustment I cant se doing it for a while...its on a very long to do list☺
Alex

[multiweb]

Looking at these pics it does look very bad indeed. This fabric sheds a lot for some reason. I guess it was flocked with the wrong type of material. I've never seen such a mess before. Even a door mat is cleaner than this. It shouldn't deter anyone from flocking their scope with good quality material that is opaque across the spectrum. You get what you pay for.