Go Back   IceInSpace > Equipment > ATM and DIY Projects

Reply
 
Thread Tools Rate Thread
  #21  
Old 18-08-2015, 09:59 PM
ausastronomer (John Bambury)
Registered User

ausastronomer is offline
 
Join Date: Mar 2005
Location: Shoalhaven Heads, NSW
Posts: 2,618
Quote:
Originally Posted by mental4astro View Post

Matt, I commend you on exploring new alternatives. That is what we need more of!

WE (Australia that is) once upon a time used to create our own authority.

Today we have deferred this to outside our shores. Worse still, we shout down anyone who dares offer an alternative. I for one insist on using as much Australian know-how and products as possible in what I create and offer.
Note quite right there Alex. The process Matt is using on his scope has never been used outside of Australia. It was previously used on 2 large aperture telescopes in Australia about 4 years ago with excellent results.

Your not exploring new alternatives using 4552-90 Alex. I used it on a 10" telescope 14 years ago. 14 years ago I realised there were better choices and nothing has happened in the intervening 14 years that would cause me to change my opinion.

Cheers,
John B
Reply With Quote
  #22  
Old 18-08-2015, 10:04 PM
mental4astro's Avatar
mental4astro (Alexander)
kids+wife+scopes=happyman

mental4astro is offline
 
Join Date: Jun 2008
Location: sydney, australia
Posts: 4,979
Hooray! Some more logic in the conversation! One key here is the Obsession design. It is a very heavy, 30 year old but brilliant design. But that is not the only point. It is important to understand why the combination of PTFE (Teflon) and textured laminates work, and why a less textured laminate WILL work just as well. This is something that the Good Book does not explain well. What Matt is coming up with is wonderful, and my comments should not be taken out of context.

With 4552-50, the surface is highly textured and in practical terms only has a small surfahttp://www.iceinspace.com.au/forum/showthread.php?p=1196879#post119687 9ce contact with the PTFE at any one time. Critical to this is the flow point of the PTFE which coincides with the Golden Rule of 15lb/sq inch.

Now, use a less textured surface, and the effective surface area that is in immediate contact with the PTFE is significantly higher per square inch compared to the 4552-50. So to achieve the same flow characteristics with a less textured surface, the Golden Rule ratio needs to change to greater than 15lb. Closer to and even higher than 20lb/sq inch. In other words, the PTFE pads get smaller.

A glossy laminate will actually work too! But the PTFE needs to be a sharp point, which when put under load will deform until the flow point is achieved, and a dob will actually move just as well as with 4552-50. The problem here is that the PTFE will abrade quickly, increasing its surface area and so the quality of the action goes down hill quickly. This is not the problem when using textured laminate until the laminate itself eventually wears away.

4552-90 is as effective as 4552-50. The Golden Rule needs to be altered to suit.

4552-90 is still in production. I ordered more of it last week from the Australian importer.

Last edited by mental4astro; 19-08-2015 at 02:57 PM. Reason: tempering language.
Reply With Quote
  #23  
Old 18-08-2015, 11:02 PM
ausastronomer (John Bambury)
Registered User

ausastronomer is offline
 
Join Date: Mar 2005
Location: Shoalhaven Heads, NSW
Posts: 2,618
Quote:
Originally Posted by mental4astro View Post
4552-90 is still in production. I ordered more of it last week from the Australian importer.
No it's not

What your Australian Importer (HVG Building Supplies) is supplying you with is material that was actually manufactured some months ago. The current worldwide stock may last a few more years yet, who knows. The 4552 pattern type is not all that popular so it may take a while for stocks of 4552-90 to become exhausted.

4552-90 is no longer listed on the Wilsonart USA Website (the company that actually makes the stuff) and hasn't been for a couple of months.

In fact the whole Wilsonart #90 textured finish has been discontinued, not just in the 4552 pattern, it's gone right across the board.

Ebony Star (4552) is currently being manufactured in 4 different finish types #1, #7, #22 and #60. . You will note there is no #90 listed, she's long gone.

The current production Wilsonart finish types can be found here.
Of these finish type #35 will most likely be the best for telescope use, but it will be in a different pattern type to Ebony Star (4552); as Ebony Star is not manufactured in Finish type #35.

Cheers,
John B
Reply With Quote
  #24  
Old 18-08-2015, 11:09 PM
ausastronomer (John Bambury)
Registered User

ausastronomer is offline
 
Join Date: Mar 2005
Location: Shoalhaven Heads, NSW
Posts: 2,618
Quote:
Originally Posted by mental4astro View Post
One key here is the Obsession design. It is a very heavy, 30 year old design.
It depends on your telescope needs. While the design may be 30 years old it is sometimes still the best option, it depends on the individuals needs.

If weight and transportability are important considerations then the newer lightweight compact designs are clearly the best choice. If however, weight and transportability are less important than stability and the ability to fit a drive system, then the Obsession design is still better than most IMO. I have used a few different compact scopes and while they are much more portable / transportable than the Obsession / SDM design, they fall short in some other areas for mine, most notably in stability at the top end.

Cheers,
John B
Reply With Quote
  #25  
Old 19-08-2015, 12:19 AM
Steffen's Avatar
Steffen
Ebotec Alpeht Sicamb

Steffen is offline
 
Join Date: Feb 2010
Location: Toongabbie, NSW
Posts: 1,965
Whatever you do, make sure you switch your search engine to safe mode before searching for ebony star
Reply With Quote
  #26  
Old 19-08-2015, 04:33 AM
mental4astro's Avatar
mental4astro (Alexander)
kids+wife+scopes=happyman

mental4astro is offline
 
Join Date: Jun 2008
Location: sydney, australia
Posts: 4,979
I have reviewed my arguments in my posts below. It is easy to misinterpret people's meaning and intentions some times, and then react in a way which with hindsight is inappropriate. My ego is not so stubborn that I cannot own up to this.

From my side of things, as materials change with fashion and technology, we need to embrace this chsnge. Otherwise we would still be driving Model-T's. It also means we cannot be so pigheaded to recognize when materials are no longer available. The older materials and designs we owe a lot to. They still work. Very bloody well. I guess a compromise would be to find allternatives that will allow theold and new to both grow with the new materials that are replacing the old as these will eventually disappear, but we will still want to build our scopes.

I guess I am also saying we need to understand why the old materials worked, what is currently available that when adapted will do the job, and have an open mind to the alternatives and be prepared to use and acknowledge these.

Alex.

Last edited by mental4astro; 19-08-2015 at 03:37 PM.
Reply With Quote
  #27  
Old 19-08-2015, 09:18 PM
dave brock's Avatar
dave brock
Registered User

dave brock is offline
 
Join Date: Dec 2011
Location: hamilton nz
Posts: 82
Quote:
Originally Posted by mental4astro View Post

I also see some people saying you need to use "this" and not "that" model of Ebony Star.

What I do not see is anyone with any actual practical experience with repeated mount construction who in turn has used all manner of different laminate varieties. Sincerely,

Alexander Massey.
The recommendations I've made have certainly been from experience gained from making over 50 telescopes combined with over 35 years making laminate benchtops.
I've tried WilsonArt #50 and #90, Laminex Dimension, Pionite Texture and Formica Quarry. While the others "work", the #50 has been noticeably better with Quarry second and Dimension third. In NZ at least, Quarry is more textured than #90.
I still have various amounts of #50, Dimension and Quarry laminates but when I've used up my supply of #50 I'll be using the WilsonArt Aeon 35 finish.
I've compared #50 and 35 by sandwiching Teflon between them and seeing which slides more. They appear equal. Surprising, because the 35 doesn't seem textured enough but it does have a new type of coating. It's certainly easier to clean (ball point ink for e.g.) than any other laminate.
In my view the Aeon 35 is a better alternative than #90. YMMV.

Dave
Reply With Quote
  #28  
Old 20-08-2015, 04:20 AM
dreamstation's Avatar
dreamstation (James)
Registered User

dreamstation is offline
 
Join Date: Jun 2015
Location: Fraser Coast QLD
Posts: 159
Hey guys

My intention with this thread was not to create tension between fellow members and I apologize for that. As a beginner I am merely after some advice from people with more experience in these matters in the hopes that it would help myself and any other members seeking the same knowledge. I'd love to be able to try everything but as most people do I have a time and money budget so we have to rely on what other people have already tried and experienced.

It hasn't all been bad however as some potentially strong contenders for a replacement of the traditional ebony star have been named. I was generally curious as to what professionals use as an alternative as stock levels continue to drop.

Thanks.
Reply With Quote
  #29  
Old 20-08-2015, 06:16 AM
mental4astro's Avatar
mental4astro (Alexander)
kids+wife+scopes=happyman

mental4astro is offline
 
Join Date: Jun 2008
Location: sydney, australia
Posts: 4,979
Then Aeon 35 looks like the way to go for large instruments. Now to change my order... pixie dust needed here for luck. Thanks Dave. I should have looked more closely at your post.

Talk has been made that for lighter instruments 4552-90 seems to be a better alternative. Considering that the heaviest instrument I make (16" to 20"), start from 40kg total for the 16" (OTA & mount), and the other scopes max out at 21kg total for 12", I may consider needing to have both 4552-90 and Aeon 35 at hand. This would then give the best performance to each type. Won't change my order then just yet. Some more investigation needed.

Fruitful thread James.

Last edited by mental4astro; 20-08-2015 at 07:15 AM.
Reply With Quote
  #30  
Old 12-09-2015, 08:41 PM
Kunama
...

Kunama is offline
 
Join Date: Sep 2012
Posts: 3,588
Follow up on this discussion .....
I have now finished my scope and my azimuth bearing seems to be a success !!!

I ended up using 3mm aluminium plate which I sanded with 180 grit and then powder coated in AztecGold. I did however find a use for the Laminex Dimensions as well, it is now my UTA baffle. Being the postforming grade it worked out only 80 grams heavier than 1mm 3ply, and came in a nice glossy black......
Pics soon on my build thread.
Reply With Quote
  #31  
Old 24-05-2017, 05:41 PM
Astromaniac's Avatar
Astromaniac (John)
Registered User

Astromaniac is offline
 
Join Date: Nov 2009
Location: Macedon, Vic. Australia
Posts: 37
Ebony Star

While looking for sources of laminate for the 16" I'm building I came across this thread. I have been looking all over the place for the Ebony Star and I have seen countless discussion on forums about the demise of it. It looks like it is still in production because it is still sold all over the world albeit with hefty delivery charges to Australia. Last week I requested a sample of the Ebony Star laminate from Wilsonart (still advertised on their web site) and received it in a few days. On their web side there is also a list of dealers of their products. Two days ago I emailed the Victorian distributor, HVG in Derrimut Victoria and they had two sheets of Ebony Star in stock. I bought one, I had to buy the full sheet, 1830x765, for $102.08 pick-up I'll keep it for future project or maybe sell the left over at an enormous profit. Here is HVG full address:
Halifax Vogel Group Pty Limited
25 West Park Dr, Derrimut, Vic 3100 tel. 03 9394 3100. Web: www.hvg.net.au.

Cheers,

John
Reply With Quote
  #32  
Old 25-05-2017, 02:41 PM
Astromaniac's Avatar
Astromaniac (John)
Registered User

Astromaniac is offline
 
Join Date: Nov 2009
Location: Macedon, Vic. Australia
Posts: 37
A qualification: Ebony Star 4552-90 not, at the moment, the 4552-50.
I'll find out and report.

Cheers,
John
Reply With Quote
  #33  
Old 26-05-2017, 12:10 PM
Astromaniac's Avatar
Astromaniac (John)
Registered User

Astromaniac is offline
 
Join Date: Nov 2009
Location: Macedon, Vic. Australia
Posts: 37
Collected the Ebony Star from HVG (a long drive from Macedon). Asked the question about the 4552-50 and it is out of production. However it is sold in Europe by Spheretec, http://www.spheretec.de/10022.php. Delivery costs could be a problem. I'm sure there are other selling the 'good stuff' but I can't remember who and where I've seen them.
That's a search for another cloudy/rainy day.

Cheers,

John
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 07:14 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Bintel
Advertisement
Testar
Advertisement