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Best cotton wool for cleaning primary


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Hi guys recently tried cleaning my 10" primary 1/10th Orion optics. I tried submersing in water for 10 minuets  with a few drops of washing up liquid.

Used a shower head to try and get grub off. Then a final rinse with distilled water. But its not really worked well enough. So am thinking of submersing in water again

And gently dragging the surface with cotton wool. Does anybody have any ebay links of brands of cotton wool. That are safest for this ? What should i be using ?

  I have seen the fingertip method of rubbing the primary. But feel cotton wool submerged can be a lot lighter. I am also using this distilled water from the ebay. Which seems good quality. But again hard to know what to trust ?

Distilled Water 1L Pure Chem | eBay

Any discussion appreciated as these mirrors are not cheap. And i want to get it right.

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Instead of cotton wool you could get a box of zeiss optical wipes. Each wipe is individually packaged and so is clean and free from particulate contamination, and already impregnated with cleaning solution (Isopropanol & ethanol, a preservative mixture of : 5 - chloro - 2 - methyl - 2 H - isothiazol - 3 - one and 2 - methyl - 2 H - isothiazol - 3 - one (3:1).

Currently less than £15 for a box of 200 online. 

I use these and gently drag over the mirror surface from inside to outside, fresh wipe for each drag (after blowing or rinsing all the dust and loose material off first).

 

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Posted (edited)
18 minutes ago, CraigT82 said:

Instead of cotton wool you could get a box of zeiss optical wipes. Each wipe is individually packaged and so is clean and free from particulate contamination, and already impregnated with cleaning solution (Isopropanol & ethanol, a preservative mixture of : 5 - chloro - 2 - methyl - 2 H - isothiazol - 3 - one and 2 - methyl - 2 H - isothiazol - 3 - one (3:1).

Currently less than £15 for a box of 200 online. agreed

I use these and gently drag over the mirror surface from inside to outside, fresh wipe for each drag (after blowing or rinsing all the dust and loose material off first).

 

Hi Craig. The optical wipes being Zeiss can be trusted to be free of contaminants agreed.  I seem to get sleeks with the slightest pressure. As such I still feel cotton submerged lightly floating over the mirror is my safest bet. Sleeks can be a hit and miss affair whatever is dragged over the surface. Would feel more comftortable doing techniques i have done before. But i am unsure of the best quality cotton wool. 

 

Edited by neil phillips
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I did my 300PDS last year, I just used supermarket cotton wool, there was no issue with streaking or contaminants.

This removed all of the surface muck and then the most effective thing I found was using a sprayer like this https://www.amazon.co.uk/Hozelock-0-5L-Spraymist-Trigger-Sprayer/dp/B0017RKEJM/ref=sr_1_26?dchild=1&keywords=sprayer&qid=1615718387&sr=8-26 with the distilled water (I have lots of this from working on cars). I found it incredibly effective at shifting any small bits of dust/hairs and left no marks at all.

 

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Last time I did one of mine; began with an air blower, then any stubborn fibres are gently swept using a fine sable haired paint brush. Next I placed the mirror i.e. 14" into a small inflated paddling pool and resting flat on a foam mat and pour over RO Distilled marine type III, to soak. The water is available in 5 litre containers and I get this free, after purchasing the container (with a tap fitted) at a local garden centre aquarium. I have only used cotton wool balls once, very lightly placing them on the mirror surface once wet and pouring some water over, before lightly lifting. I used some we had in the house which seemed fine, although the recommendation above for surgical grade cotton wool from a chemist is a preferred option. Also a good idea as suggested above for a trigger sprayer, something to consider for next time. 

To prevent streaks and marks forming, prop the mirror up, use a hair dryer on cold setting. Surplus distilled water (plenty left over from a 5 L container) store in a dark cool location.

The finger method, will that not potentially leave residue from the finger tips and how light can you apply this?

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2 hours ago, scarp15 said:

The finger method, will that not potentially leave residue from the finger tips and how light can you apply this?

As lightly as you can you touch something lol. Very lightly I would suggest. The advantage is that the cotton wool can catch something and drag it across the mirror without you noticing. This can be felt with fingers. It's not possible for your fingers to actually scratch the coating the skin is softer than the mirror coating, it is particles of grit you need to worry about. You wash your hands with pure soap first as per the method. The last disadvantage of cotton wool is that I find it always leaves little fibers on the mirror. 

For a refractor I use cotton wool as you can't run water over it. 

Edited by Adam J
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5 hours ago, JSeaman said:

I did my 300PDS last year, I just used supermarket cotton wool, there was no issue with streaking or contaminants.

This removed all of the surface muck and then the most effective thing I found was using a sprayer like this https://www.amazon.co.uk/Hozelock-0-5L-Spraymist-Trigger-Sprayer/dp/B0017RKEJM/ref=sr_1_26?dchild=1&keywords=sprayer&qid=1615718387&sr=8-26 with the distilled water (I have lots of this from working on cars). I found it incredibly effective at shifting any small bits of dust/hairs and left no marks at all.

 

Used a shower head to do similar. The primary needs contact cleaning unfortunately

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4 hours ago, Adam J said:

I find that for mirrors the finger method is superior. 

Please elaborate. I am interested in peoples experiences. And finding the safest way to clean this. If the finger tip method is the best. Then i should certainly be doing it

Thanks for the feedback

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2 minutes ago, neil phillips said:

Please elaborate. I am interested in peoples experiences. And finding the safest way to clean this. If the finger tip method is the best. Then i should certainly be doing it

Thanks for the feedback

I too use the fingertip method. I degrease my hands and then use a sprayer water mix to soak the mirror, hands sprayed too- the soap is a lubricant. Works for me.

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2 hours ago, Adam J said:

As lightly as you can you touch something lol. Very lightly I would suggest. The advantage is that the cotton wool can catch something and drag it across the mirror without you noticing. This can be felt with fingers. It's not possible for your fingers to actually scratch the coating the skin is softer than the mirror coating, it is particles of grit you need to worry about. You wash your hands with pure soap first as per the method. The last disadvantage of cotton wool is that I find it always leaves little fibers on the mirror. 

For a refractor I use cotton wool as you can't run water over it. 

Your fast convincing me this is what i should do. Thanks for the discussion

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9 hours ago, neil phillips said:

Hi guys recently tried cleaning my 10" primary 1/10th Orion optics. I tried submersing in water for 10 minuets  with a few drops of washing up liquid.

Used a shower head to try and get grub off. Then a final rinse with distilled water. But its not really worked well enough. So am thinking of submersing in water again

And gently dragging the surface with cotton wool. Does anybody have any ebay links of brands of cotton wool. That are safest for this ? What should i be using ?

  I have seen the fingertip method of rubbing the primary. But feel cotton wool submerged can be a lot lighter. I am also using this distilled water from the ebay. Which seems good quality. But again hard to know what to trust ?

Distilled Water 1L Pure Chem | eBay

Any discussion appreciated as these mirrors are not cheap. And i want to get it right.

Any Surgical grade cotton wool balls

Most others may contain bits of husk etc which may scratch your mirror, check manufacturers site before buying.

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I found a thread on CN about this method. Some big names in the industry recommend the fingertip method...

https://www.cloudynights.com/topic/331653-how-to-clean-your-telescope-mirrors-cheap-and-easy

i too am at the point where I need to give my OO 1/10th 12” its first ever clean

Magnus

Edited by Captain Magenta
misspelled my own name!
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1 hour ago, neil phillips said:

Just noticed your using a Antares 1/30th. Just installed mine. Do you know if the secondarys are silicon over coated. 

not to sure. i seem to remember what you say is correct though. only bought it xmas

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1 hour ago, Captain Magenta said:

I found a thread on CN about this method. Some big names in the industry recommend the fingertip method...

https://www.cloudynights.com/topic/331653-how-to-clean-your-telescope-mirrors-cheap-and-easy

i too am at the point where I need to give my OO 1/10th 12” its first ever clean

Magnus

I go against the grain and use more dish soap that many say, not by much just a couple of good squirts. I use RO water ie a couple of Aquafinas. Spray the soap water mix on and keep spraying until all lose junk is off, then its nice and lubed. Spray de greased hands and use finger tips then repeat soap rinse, Final rinse is pure water, no fingers involved. The soap is a lube so no scratches.

Edited by jetstream
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I prefer cotton wool but each to their own. Look for “Cotton wool BP” on the label in the UK. BP = British Pharmacopedia = medical grade

Light touch is a given but I also try to rotate the cotton wool as I move it across the surface so the overall effect is lifting rather than polishing. One swipe per cotton wool ball then discard. Imagine you’re a nurse trying not to cross contaminate different parts of the mirror surface.

There used to be a great video online of David Sinden cleaning a refractor lens with the proper technique but I’m not sure it’s available anymore.

My worry is always dragging whatever’s on the surface over the surface. It’s not exactly analogous but next time there’s a sunny day look at the reflection of the sun on a car bonnet. What you’ll see is scratches in a circle around the reflection of the sun. That’s because there will be scratches in random directions all across the bonnet and it’s the ones in a circle around the solar reflection that bounce back to your eye. Why are there scratches in all directions on car bonnets? Because when cars get washed whatever’s on the bonnet usually gets dragged across it before it gets removed.

There’s a huge difference between cars and telescopes but as a general principle if you assume whatever’s on the surface of your mirror and could be abrasive and think about your technique from that starting point you won’t go far wrong.

 

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12 minutes ago, hunterknox said:

I prefer cotton wool but each to their own. Look for “Cotton wool BP” on the label in the UK. BP = British Pharmacopedia = medical grade

Light touch is a given but I also try to rotate the cotton wool as I move it across the surface so the overall effect is lifting rather than polishing. One swipe per cotton wool ball then discard. Imagine you’re a nurse trying not to cross contaminate different parts of the mirror surface.

There used to be a great video online of David Sinden cleaning a refractor lens with the proper technique but I’m not sure it’s available anymore.

My worry is always dragging whatever’s on the surface over the surface. It’s not exactly analogous but next time there’s a sunny day look at the reflection of the sun on a car bonnet. What you’ll see is scratches in a circle around the reflection of the sun. That’s because there will be scratches in random directions all across the bonnet and it’s the ones in a circle around the solar reflection that bounce back to your eye. Why are there scratches in all directions on car bonnets? Because when cars get washed whatever’s on the bonnet usually gets dragged across it before it gets removed.

There’s a huge difference between cars and telescopes but as a general principle if you assume whatever’s on the surface of your mirror and could be abrasive and think about your technique from that starting point you won’t go far wrong.

 

Thanks for the info on BP british Pharmacopedia = medical grade. I was always of the opinion you should not touch a mirror. So always used cotton. But i can see some merit in doing that way. Certainly a split of opinion on this it seems.

As fas as distilled water is concerned there is so much choice and price variance. Hard to know which to trust. Anyone have any ideas about the purest distilled water ?

Great discussion guys. Its most certainly helpful

 

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HIi i have a fuller scopes 6inch reflector, I made a stand off cover for the mirror and this helped to keep off most  grunge 

 I still have a copy of the fuller scopes catalogue and there is a paragraph that covers the cleaning of the mirror which I have followed on the very rare occasion when it needed a clean.

ie immerse the mirror in Luke warm water which has had pure soap flakes dissolved in it, leave to soak for a while then rinse off under tap

repeat this and swab the surface with a lint free cloth.

remove the mirror and rinse in chemist distilled water stand the mirror on edge and let the water run off any drops of water that remain can be picked off with blotting paper this  worked for me this was written  in the 60s just like to add that my mirror is 1.25 thick and only 6inches in diameter so it stands on its own with no problems this may help   

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