James, I don't want to hijack this thread into a discussion of Ebony Star, and I should have been a little more cautious about this. My apology Tim.
But I need to clarify the situation now that is up.
Ebony Star CAME in two textures, as you pointed out James. 4552-50 is the more textured one, 4552-90 is not as textured. BOTH work, though 4552-50 has been preferred for scope bearings. The textured laminates that were produced by Laminex and Formica were also recommended, and again if 4552-50 was not available, these were considered close to equal to 4552-90.
Now, 4552-50 has not being in production for close to ten years (from my understanding). The textured laminates by Formica and Laminex were also discontinued soon after. The ONLY textured laminate that is still produced is by Wilsoart, and of the textured laminates they produce, 4552-90 is still the most highly textured, and it is still more textured than the laminates produced by Formica and Laminex.
HOW GOOD IS THE REMAINING EBONY STAR 4552-90?
Best way I have is to give my own personal scope building experience.
In the first scope I built, I used Ebony Star on the az. bearing. As it happened, it was 4552-50. I did not know any better of the texture differences 20 years ago, but the piece I got did surprise me at how textured it was. But for the altitude bearing I used an iron-on laminate that was no where as textured. Both axis also use Teflon pads. The scope works beautifully (I still have this scope, and it happens to also be a 10" dob). The scope was designed to follow John Dobson's principles of large diameter bearings, a balanced OTA and careful material selection. When the bearing surfaces are clean and waxed, I cannot say I notice a difference in the action of both axis.
Scopes I have built since that instrument (and prior to starting Gondwana Telescopes), I have used a few different laminates on the bearings, none of which was Ebony Star of either type. What they all had in common was a textured surface. The action of all these scopes is not just governed by the laminate. Bearing design is also a major part of the action. All these scopes I have built all work very smoothly in their action. I have had many experienced dob users exclaim to me how lovely the action of these instruments is, all far better than mass production instruments. Remember, I had not used Ebony Star with these scopes, only laminates that were as textured as I could get my hands on.
When I started Gondwana Telescopes, I knew that the type of laminate I used would be judged upon, wrongly or rightly. What I always wanted to offer is the best materials I could offer. My sourcing of Ebony Star led me to situation as I understand it now on textured laminates. So as things stand for my production capacity, 4552-90 is the only textured laminate that is still available. Is it any good? Please ask anyone who has handled my scopes. Better still if you can handle them yourself to judge for yourself. Jason, I will be at Astrofest over the second weekend of its running. I will have there three Gondwana scopes, two of which have Ebony Star 4552-90, the other scope has a non-Ebony Star textured laminate. You, and everyone else too for that matter, are always welcome to come and have a feel of the action of these instruments. It is the only way you can actually understand what a dobsonian scope
can actually feel like.
Laminate quality is only one part of the dob equation. Above this actually is bearing design! Design the bearings properly, and work with the centre of gravity of the OTA, and as long as the laminate is textured and you keep it clean and waxed, it will work like a charm.
~x.X.x~
Yes, I can supply fellow scope builders with Ebony Star. I can also cut to size. Price depends on the size sought as this also affects packing (a strip can be coiled, a sheet needs to be sent flat and padded) and postage.
I will need to address this in a more formal way in IIS, probably as an article, shortly. I will speak to the Iceman about this.
Again, Tim, my apology for the hijacking of your thread.