Sharing Wilsonart Laminate Sheet for Dob Bearings

[Brickbots (Richard)]

Hello!

I'm in the process of rebuilding my 16" scope, and I've been on the prowl for an appropriate laminate to use with PTFE (Teflon) pads.

Seeing as Ebony Star is hard to find, I ordered several samples of other Wilsonart laminates that have been suggested and was pretty pleased with the #45 finish. It has a nice bit of relief and seemed to glide well on teflon with minimal stiction.

I'm just about ready to pull the trigger and order some, but I can't seem to locate anyone in Sydney who will sell less than a 1830 x 1530 sheet. I need a square meter at most, so this leaves quite a bit of extra. With all that said...

- Has anyone sourced any laminate recently? Is there anything better than the #45 finish available?
- Does anyone have a lead on a supplier in Sydney I may have missed?
- If a full sheet of something with #45 finish is my best option, is anyone in the Sydney area interested in sharing the materials?

Thanks for any advice... this laminate is the last bit I need to finish the project and it's been terribly difficult to find a supplier.

[dave brock]

Have you tried kitchen joinery companies? Particularly ones that make kitchen benches,

Dave

[Kunama]

Richard, I used powder coated aluminium for both my alt and azimuth bearing surfaces, works brilliantly.

My azimuth bearing is a 600x600x3mm aluminium plate powder coated in Aztec Gold and glued to the base of the rocker box. Alt bearings are cast aluminium but powder coated strips glued to the current bearings works too.

Allow the powder coat to harden for a week before fitting it out.

Teflon pads glide on it ever so nicely. Due to the weight of my scope I fitted a teflon pad around the centre pivot and shimmed it up 0.6mm.

[Brickbots (Richard)]

Hi Dave! No, but that is a great idea. I was going more through the authorized distributers/wholesalers but maybe I should move one step down the food chain, especially as I'm after the scraps

Sounds like it might be a fair bit of calling around, and being grunted at, but it might come to that. Thanks for the suggestion!

Originally Posted by dave brock

Have you tried kitchen joinery companies? Particularly ones that make kitchen benches,

Dave

[Brickbots (Richard)]

I've heard of people using this for cast aluminium altitude bearings, and I suppose it should work just as well for the azimuth bearings.

The idea would be to purchase really thin aluminum sheet stock, cut it (water jet?, hand snips?), and then powdercoat it and glue it as if it were laminate?

Seems like it might work out a bit more expensive than standard laminate, but I've never priced powdercoating. The laminate seems to run ~ $50 per sq meter, but that gets a bit pricy if it's a whole sheet...

What made you decide on aluminium for the azimuth bearing? Was it to match the motion of the altitude ones, or is the motion really much nicer than PTFE/laminate?

Originally Posted by Kunama

Richard, I used powder coated aluminium for both my alt and azimuth bearing surfaces, works brilliantly.

My azimuth bearing is a 600x600x3mm aluminium plate powder coated in Aztec Gold and glued to the base of the rocker box. Alt bearings are cast aluminium but powder coated strips glued to the current bearings works too.

Allow the powder coat to harden for a week before fitting it out.

Teflon pads glide on it ever so nicely. Due to the weight of my scope I fitted a teflon pad around the centre pivot and shimmed it up 0.6mm.

[Kunama]

Another option Richard,
I wanted some post forming laminate for the baffle on my Dob, went to the Canberra Laminex Group warehouse, was directed to the loading dock to see the warehouse supervisor there who gave me a full sheet of discontinued laminate in black for the cost of a case of beer.

[Rod]

Hi Richard

One option for the altitude bearings I have used is the plastic strapping you see in Bunnings for wrapping bundles of timber. It is a little more slippery than ebony star but gives a very smooth motion and it's free.

I get my laminate from a place near me that sells offcuts. I was able to get ebony star that way. I noticed that there is this place in Sydney advertising on eBay which appears to be similar:

http://pages.ebay.com/link/?nav=item...obalID=EBAY-AU

Whatever azimuth laminate you use, I find polishing it with silicone based car polish improves motion significantly. I don't usually find it necessary for the altitude bearings.

Rod

[Brickbots (Richard)]

Hey Rod,

Thanks for the ebay link, I'm feeling a bit sheepish that I did not think about calling some cabinet makers/joinery shops as you and Dave suggested. I see that Trademaster (the company in the ebay link) is open on Saturdays. If I don't find anything before I'll have to grab some teflon and head down there to see what I can find.

Originally Posted by Rod

Hi Richard

One option for the altitude bearings I have used is the plastic strapping you see in Bunnings for wrapping bundles of timber. It is a little more slippery than ebony star but gives a very smooth motion and it's free.

I get my laminate from a place near me that sells offcuts. I was able to get ebony star that way. I noticed that there is this place in Sydney advertising on eBay which appears to be similar:

http://pages.ebay.com/link/?nav=item...obalID=EBAY-AU

Whatever azimuth laminate you use, I find polishing it with silicone based car polish improves motion significantly. I don't usually find it necessary for the altitude bearings.

Rod

[speach (Simon)]

Whats wrong with getting a bit of Teflon? Easy to get and very slippy or Polytetrafluoroethylene (PTFE) very very slippy and easy to get.

[Kunama]

Originally Posted by speach

Whats wrong with getting a bit of Teflon? Easy to get and very slippy or Polytetrafluoroethylene (PTFE) very very slippy and easy to get.

But it has to glide on something that provides just the right amount of stiction, that's where the laminates or powder coated aluminium comes in.

alternately you could get a 600x600 sheet of teflon and small laminate pads but you wouldn't be able to afford food for a few weeks.......

Here is my solution:
600x600x3mm aluminium plate powdercoated in Aztec Gold and the ground board with 4mm thick PTFE pads at 45º to the direction of movement, edges of pads are bevelled to glide over any imperfections in the powder coating. Pivot bolt with brass bushing and PTFE pad under the middle to reduce the perimeter load, this pad is shimmed 0.6mm with aluminium shim.

Smooth as silk

[mental4astro (Alexander)]

I carry Ebony Star that I use on the scopes and mounts I build, and am happy to supply it. I can also cut to size and shape.

That's a neat solution too, Matt

Alex.

[tempestwizz (Brian)]

Taking heed of other atmers within my club, I've now built three dobs ranging from 10" to 18" and have confirmed that Teflon running against aluminium seems to be ideal. I've not used powder coated aluminium. Just raw aluminium which can be polished with scotch rite scrubbers. There is enough stiction to hold, but there is no 'grab then jump' as you try to delicately move at high magnifications.
I recommend this approach.
BC

[DJT (David)]

Originally Posted by mental4astro

I carry Ebony Star that I use on the scopes and mounts I build, and am happy to supply it. I can also cut to size and shape.


Alex.

Hi Alex

pm sent on that offer. Cheers