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Replacing Felt Inside Tube Rings With Microfiber?

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#1 Dave Hederich

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Posted 02 October 2022 - 11:23 AM

I was about to go off searching for some thin felt to replace the badly worn felt inside my ST80's tube rings when the thought struck me that microfiber cloth has many of the same characteristics as felt and I have extra laying around the house that's roughly the same thickness as the ring felt. A quick search of CN and other astronomy sites showed no mention of this idea so I assume it's not a common replacement. I'd appreciate anyone's thoughts on how well you think this might work.



#2 CeeKay

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Posted 02 October 2022 - 11:36 AM

Dave, I'd think that there would probably be no difference between the two, other than how they are made (felt is from animal wool, microfiber is synthetic).

 

I'm a custodian at a local school and use microfiber to clean with.  The one thing to watch out for is that microfiber is a magnet for things like bark dust/chips.

 

Chris



#3 Couder

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Posted 02 October 2022 - 12:01 PM

Microfiber also seems slicker, so you might watch out for slippage.


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#4 Dave Hederich

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Posted 03 October 2022 - 01:42 PM

Thanks for the input. If no one else has tried this then the only way for me to know is to try it myself. If it doesn't work then it will be easy enough to peel off the microfiber cloth and replace it with felt. I've read that rubber cement is good to use because it's sticky enough to hold but not so sticky that it's difficult to peel off. I'll report the results here. But it might take me a few days to get around to this as I currently have several other projects going.



#5 archer1960

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Posted 03 October 2022 - 01:53 PM

I suspect the microfiber might be a little more compressible than the felt, so you might need to put a slightly thicker layer on, and then crank it down a little tighter. But it should still work, depending on how it is installed.


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#6 Tonk

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Posted 04 October 2022 - 12:22 PM

I stiffened the felt in my scope rings with a plasticiser made from PVA (polyvinyl acetate) disolved in IPA (isopropyl alcohol).

I removed the felt by peeling it away from the glue bonding it to the aluminium rings. The felt ws then soaked for 24 hours in the clear PVA/IPA gum, hand squeezing out air bubbles (wear rubber gloves). The felt was then roughly shaped to fit back to the rings and left to air dry until dry and stiff but still bendable. It was then glued back into the rings and the OTA replaced and the rings clamped down on the OTA barrel for two weeks. After two weeks I released the ring clamps to expose the now glassy plasticised felt. The felt is now smooth and very stiff but still compressable enough to grip the OTA.

This fully solved an issue I had with the OTA slowly settling in the felt lined rings after a meridian flip.


Edited by Tonk, 04 October 2022 - 12:23 PM.

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#7 joshman

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Posted 04 October 2022 - 04:37 PM

I stiffened the felt in my scope rings with a plasticiser made from PVA (polyvinyl acetate) disolved in IPA (isopropyl alcohol).

I removed the felt by peeling it away from the glue bonding it to the aluminium rings. The felt ws then soaked for 24 hours in the clear PVA/IPA gum, hand squeezing out air bubbles (wear rubber gloves). The felt was then roughly shaped to fit back to the rings and left to air dry until dry and stiff but still bendable. It was then glued back into the rings and the OTA replaced and the rings clamped down on the OTA barrel for two weeks. After two weeks I released the ring clamps to expose the now glassy plasticised felt. The felt is now smooth and very stiff but still compressable enough to grip the OTA.

This fully solved an issue I had with the OTA slowly settling in the felt lined rings after a meridian flip.

This is a fantastic solution, but I need to know, how did you even diagnose the issue of the scope settling in the felt?



#8 Tonk

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Posted 05 October 2022 - 03:52 AM

Star trailing in images taken immediately after the flip but not before the flip or well after the flip. I.e. there was a prolonged settling period



#9 luxo II

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Posted 05 October 2022 - 04:17 AM

The material used long ago was cork, and you can buy 1mm sheets from craft shops.

I’m a bit puzzled how you would secure microfibre (or similar fabrics) and the glue will soak in making the fabric fairly hard…

#10 mikerepp

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Posted 05 October 2022 - 05:34 AM

Ever try cutting microfiber?   It does not stay together well, you'll have bits of the stuff everywhere.



#11 Dave Hederich

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Posted 05 October 2022 - 09:21 AM

The material used long ago was cork, and you can buy 1mm sheets from craft shops.

I’m a bit puzzled how you would secure microfibre (or similar fabrics) and the glue will soak in making the fabric fairly hard…

Not an issue with rubber cement which stays flexible when dry without becoming hard. Apply rubber cement to the rings, let air dry for a few minutes to become tacky and then apply material of choice.

 

Cork is another good option, especially if as mikerepp suggests the microfiber comes apart when cut. I have never cut microfiber so I won't know if it will fray until I try it.




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