Achernar
Postmaster
Reged: 02/25/06
Posts: 5025
Loc: Mobile, Alabama, USA
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Today I was looking for some Ebony Star Formica for my 15-inch Dob that is being built right now. In fact, I mostly finished the mirror box and the altitude bearings. But I got a surprise when the salesman told me Wilson Art no longer makes the stuff. Has anyone here found another kind of Formica that works well or knows where I can find some Ebony Star? I need enough to cover two hollow arc 12-inches in radius and a rocker box that will be about 20-inches square.
Taras
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15-inch F/4.5 Dob under construction
10-inch F/4.5 Discovery Dob
6-inch F/8 Homebuilt Dob
4 1/4-inch F/4 Homebuilt reflector
A whole bunch of eyepieces, filters and other accessories....
Two curious cats
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davidc
sage
Reged: 11/24/05
Posts: 263
Loc: Mesa, Arizona
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Teras,
I use Fiberglass Re-inforced Plastic for my altitude bearings, and I can move my ota up and down with 2 fingers. I was told that is what was popular before Ebony Star came around. I cemented them down with contact cement, and 2 c-clamps. Cut into strips with an electric jig saw with a fine blade. I bought mine from a gentleman in my club. Search Google for Fiberglass Re-inforced Plastic.
David
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13.1 Inch-F/4.8 Royce Conical Homebuilt Dob
8 Inch-F/5 Orion Dob
4 Inch Celestron Reflector Camping Scope
25mm Meade W/A Ep
13mm Orion Stratus Ep
8mm Orion Stratus Ep
2X Meade Barlow
Meade Cheshire/Sight Tube
East Valley Astronomy Club
Searching For Rainbows In The Dark
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timo4352
super member
Reged: 04/16/07
Posts: 160
Loc: Northeast Ohio
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Try Scopestuff or Meridian Telescopes
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Orion 3.6CA Reflector
and 2 homebrew scopes --
8" Hubble Bubble ballscope
8" F/8 CHief - nearing completion 
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Jeff Morgan
Carpal Tunnel
Reged: 09/28/03
Posts: 1987
Loc: Prescott, AZ
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My local cabinet shop had Ebony Star strips sufficient for altitude bearings, and I got them for $5. For the ground board I would have had to custom order a 4 x 8 sheet for about $130. So, Ebony Star can still be had.
Tempting as it was, I read about #45 Facet here on CN, so I got a piece for about $10. The scope should be operational in 2-3 weeks.
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Jeff Morgan
Prescott, AZ
Wile E. Coyote School of Telescope Making
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ausastronomer
scholastic sledgehammer
Reged: 06/30/03
Posts: 936
Loc: NSW Central Coast (Australia)
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Quote:
My local cabinet shop had Ebony Star strips sufficient for altitude bearings, and I got them for $5. For the ground board I would have had to custom order a 4 x 8 sheet for about $130. So, Ebony Star can still be had.
Not for long. It is just the old stock sitting around that is available now and being bought up. Wilson Art haven't manufactured it for almost 2 years. It hasn't been available anywhere in Australia for almost a year.
Cheers,
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John Bambury
AS of NSW
AS of Hunter Valley
18"/F4.5 Obsession fully loaded with OMI optics
14"/F4.5 SDM fully loaded with Zambuto Optics
10"/F5 Newtonian with Argo Navis
Lots of Pentax XW's. 12mm & 17mm Nagler T4's, 31mm Nagler T5 & 13mm ETHOS. TV Paracorr and 1.8X TV Barlow and 2.5X TV Powermate
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Achernar
Postmaster
Reged: 02/25/06
Posts: 5025
Loc: Mobile, Alabama, USA
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How close an equivalent is #45 Facet to Ebony Star?
Taras
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15-inch F/4.5 Dob under construction
10-inch F/4.5 Discovery Dob
6-inch F/8 Homebuilt Dob
4 1/4-inch F/4 Homebuilt reflector
A whole bunch of eyepieces, filters and other accessories....
Two curious cats
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Jeff Morgan
Carpal Tunnel
Reged: 09/28/03
Posts: 1987
Loc: Prescott, AZ
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Ross Sackett (sp?) has posted about it on CN back in the late spring, results favorable. Perhaps he will notice this thread and give us an update?
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Jeff Morgan
Prescott, AZ
Wile E. Coyote School of Telescope Making
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RossSackett
professor emeritus
Reged: 08/17/07
Posts: 692
Loc: Memphis, TN
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Hi Jeff and all,
I used 45 Facet on a 6" f/5 single pole travel telescope this summer. While the scope was quite light and thus perhaps not typical, both the horizontal and elevation motions were very smooth without objectionable stiction. Its performance was comparable to old Ebony Star in a similar light 8" travel telescope. Now I wouldn't necessarily describe its motion as "buttery", which I've only felt (with Ebony Star or something else) with heavier scopes starting with "sidewalk" sonotube 6" or 8"ers.
I did the expedient teflon-block test with the microtextured 45 Facet and the golfball dimpled Formica Sparkle finishes, and they come out about the same. Next scope will be Sparkle, just to see how that works.
However, I have come to think that a bearing dressing like SailKote makes more of a difference than laminate choice. It consistently reproduces the feeling that the scope is just *oozing* in the direction I want it to go that I remember from old Ebony Star.
But even more important than that are the observer's motor habits. If you use your scope enough you naturally and unconsciously will tend to compensate for mechanical issues like friction, stiction, and scope flexure; and even for optical aberrations like stig, coma, and curved fields. Making a date with your telescope out under the stars and getting to know one another's quirks is more important than choosing the right bearing surface or plywood.
Ross
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"A craftsman relies on science when the state of knowledge allows it, tradition and experience when it does not, and makes art whenever he can."
12 scopes from 4.25 to 18" and a 24" in progress. 12 ATM awards. Webpage: http://stardazed.com/ Some more scope pix at http://www.flickr.com/photos/8315630@N04/
Anagrams: Amateur astronomer = A mature moon-starer; Dobsonian maker = Debonair as monk
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Achernar
Postmaster
Reged: 02/25/06
Posts: 5025
Loc: Mobile, Alabama, USA
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The reason why I was asking this question, is that I have found it is possible to make a telescope move too easily, as though it has ball bearings on both axis and moves in the slightest breeze. I guess I'm going to bring a piece of Teflon and look like the crazy guy asking about Formica, LOL.
Taras
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15-inch F/4.5 Dob under construction
10-inch F/4.5 Discovery Dob
6-inch F/8 Homebuilt Dob
4 1/4-inch F/4 Homebuilt reflector
A whole bunch of eyepieces, filters and other accessories....
Two curious cats
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sixela
Postmaster
Reged: 12/23/04
Posts: 10862
Loc: Boechout, Belgium
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Quote:
Today I was looking for some Ebony Star Formica
Ebony Star is a colour for a product from Wilsonart (and it's really the "Touchstone" finish you want, the colour doesn't matter).
Formica also has different textures, and apparently in Europe you want the -75 "quarry" finish and in he US the #42 "sparkle" finish.
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400mm f/4.46 self made Dobsonian on Tom Osypowski equatorial platform
Orion Starblast (114mm f/4 reflector, Alt/Az)
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kb4mxo
member
Reged: 07/17/06
Posts: 58
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Working on a 8" dob and used Wilsonart HD and works just fine. I ordered it from a local dealer and can't see using anything else.
Good luck on your project.
Steve
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Vincent Becker
super member
Reged: 09/16/08
Posts: 198
Loc: France
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On my 8" dob I used nylon strap for the altitude bearings. It works very well, is readily available and very cheap.
For the azimut motion, I used one teflon pad for stiction and two sets of roller bearings (used in rolleblades, very cheap too) on polyurethane-covered wood.
The movements are very smooth and allow to hand-track objects at 375x without difficulty.
It's hard to extrapolate if this setup will work as well on a 15". I'll give it a try on my 16" which is under construction
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Vincent Becker
10" dobsonian on EQ platform (home-made by my father)
8" string newtonian as travelscope (home-made by myself )
Orion 80ED and GSO 200/1000 on Atlas EQ-G for astro-imaging
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sec_1951
member
Reged: 01/26/06
Posts: 26
Loc: Phoenix, Arizona
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I just came across a Wilsonart laminate called Ebony Fusion 1799-7. I have been using the 45 Facet and replaced it with the Fusion. After a quick test in an alt-az for an 80 mm refractor, I think I can recommend it for further investigation by other DIYers.
My impression was that it was very smooth but with more friction than the 45. That is to say that while the movement was smoother it took more effort to make the movement. Stiction was seemingly non-existent and the small amount of backlash I had with the 45 disappeared. The increase in friction was a little problematical as you could notice the difference but the overall improvement in the motion more than made up for it.
I use 2 teflon bearings on both the alt and az surfaces and would also recommend trying that out. (ie the layout is as follows: laminate / teflon / teflon /laminate -- hope that makes sense.)
As a side note I have tried using the nylon strap as suggested by Vincent Becker and found it to be very good also. If they made that stuff in sheets it'd probably be on everyone's list.
Steve C.
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Achernar
Postmaster
Reged: 02/25/06
Posts: 5025
Loc: Mobile, Alabama, USA
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I got some good news on the Formica front. I was able to find some with the sparkle finish, and with a small piece of Teflon and Ebony Star I found it seems to work exactly the same. So I bought a large scrap piece from a local cabinet supplier and already put it on the altitude bearings. Thanks for the advice everyone, it saved me a lot of trouble.
Taras
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15-inch F/4.5 Dob under construction
10-inch F/4.5 Discovery Dob
6-inch F/8 Homebuilt Dob
4 1/4-inch F/4 Homebuilt reflector
A whole bunch of eyepieces, filters and other accessories....
Two curious cats
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ndelo
professor emeritus
Reged: 08/02/06
Posts: 529
Loc: Light-polluted New Jersey
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Quote:
Teras,
I use Fiberglass Re-inforced Plastic for my altitude bearings, and I can move my ota up and down with 2 fingers. I was told that is what was popular before Ebony Star came around. I cemented them down with contact cement, and 2 c-clamps. Cut into strips with an electric jig saw with a fine blade. I bought mine from a gentleman in my club. Search Google for Fiberglass Re-inforced Plastic.
David
I know you already found your soultion, but I have to add that the white Fiberglass Re-inforced Plastic with the bubbly surface (found in large, inexpensive sheets in Lowes or Home Depot) works great. I used it on the azimuth bearing for a homebuilt 18' dob and, after a two coats of Turtle wax, my dob has extremely buttery movements and can be pushed about with mere fingertips.
Anyone struggling to find Ebony Star can sleep well knowing that this stuff makes a fine replacement and is readily availible.
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imhotep
Pooh-Bah
Reged: 02/14/07
Posts: 1429
Loc: Tampa, FL
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FYI for anyone interested, ScopeStuff has stock on every single item listed on their website under the heading of Ebony Star.
I recently made the same discovery about Ebony Star being discontinued after placing an order with Meridian. They've several items on their website that aren't being stocked by them anymore, including kydex and teflon (their words, not mine).
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Curt
8" F5 Newtonian Astrograph
Orion 80ED CUSTOM
Edmund Optics 4.25" 'Palomar' Newtonian, 1968 vintage
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Achernar
Postmaster
Reged: 02/25/06
Posts: 5025
Loc: Mobile, Alabama, USA
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I did find FRP at the local Lowe's but I wasn't going to be using anywhere near a whole sheet of the stuff. At more than 30 dollars a sheet, it wasn't the bargain that a three by four foot piece of Formica was at five bucks. I now have enough for two, even three telescopes. Finding Formica with a Touchstone or Sparkle finish isn't easy anymore, therefore as you've pointed out FRP is a viable alternative. I would have just as soon used FRP if I could have bought a scrap piece large enough for the job.
Taras
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15-inch F/4.5 Dob under construction
10-inch F/4.5 Discovery Dob
6-inch F/8 Homebuilt Dob
4 1/4-inch F/4 Homebuilt reflector
A whole bunch of eyepieces, filters and other accessories....
Two curious cats
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arpruss
scholastic sledgehammer
Reged: 05/23/08
Posts: 858
Loc: Waco, TX
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For azimuth bearings, if the pads fit within a 12" circle, one can just drop in a vinyl record. Those can be had on ebay for no more than $2 shipped (I got one for $0.01 shipped and another for $2). I use one in my 13" and in my 8" travel scope, and Teflon on the record works great. There are also 16" radio transcription records, but they are a bit more expensive and I haven't tried them.
This won't work for alt bearings, of course, nor for larger az bearings.
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Coulter Odyssey 13.1" split-tube
Coulter Odyssey 8"
Home-made 7.8" F/4 dobsonian travel scope
Home-made 68mm F/5.3 achro (typically used as finder on 13.1")
Skymaster 15x70
BPTs4 8x30
32mm Plossl, 30mm Rini, 27mm Kellner, 13mm Hyperion, 6mm TMB/BO Planetary, Owl 2X Barlow
Palm TX with AstroInfo and RescoViewer
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