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Question for Spectralon owners - cleaning?


JMC

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I would definitely recommend going for a finer grit. I thought that 220 grit was too "scratchy" when I tried it. I use 400 and take a little more time.
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I just did all 4 of mine, and I could not be more pleased with the results!

I used the 220 grit I had, and it was fine, so I didn't finish it with the 320 grit.

The 220 I used was 3M Rro Grade Precision Wet/Dry. UPC 051141395395

It is red. Found it at Home Depot, could not find any 220 at the first place I went.

I am VERY happy with how that worked.

 

I did it like the woman in the video shows, but I put the glass sheet flat in the bottom of the sink, much easier, and had RO/DI water running on it while sanding,

so the water was constantly washing everything away and off the sand paper. My sink has a separate RO faucet hanging over the sink, so that worked perfectly.

You can really see the black washing away when you do the black disk.

 

Now this is "actual photography". ;)

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A few further ideas on cleaning and keeping your Spectralon clean.

Your Spectralon may come in a boxed set, and these sets, boxes, and foam linings may vary from one model to another over time,

but examination under 365nmm Nichia may reveal that the interior has a lot of dust and dirt, which may not blow out with compressed air very easily or entirely.

So I removed my foam and spray washed it on all sides with warm water. This got it very clean.

My particular foam lining has the rough cut surface facing down in the box, and I found a good amount of foam dust debris inside the bottom of the box under where the foam had been,

so this I also cleaned out with compressed air.

Now that everything is clean, it should help keep the Spectralon remaining cleaner longer.

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Dry sanding is recommended for the black disk! It crumbles more easily.

 

And while I am happy to hear the 220 grit worked for your disks, I do want to make it clear that 220 was too harsh on mine. So anyone contemplating sanding Spectralon, please do understand that YMMV as regards sanding grit. :lol: I would hate to see anyone scratch up their discs.

*****

 

Steve, have you sanded any PTFE? My big PTFE disc has some discoloration so I have been contemplating sanding it to see if that helps.

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Andrea, First let me tell you that if you sand your 99% white disk it will look a lot blacker in UVIVF.

The only one of my disks that looked totally black in UVIVF before sanding was the 2% black disk, now the only one that looks even a little gray is the 99% disk.

The 220 grit left no marks or scratches on my disks. They are absolutely smooth, better than before.

My disks have no cover tops, they came with glass circle covers.

I found that 52mm 'stacker' caps cover them perfectly without touching the Spectralon surface.

Thanks for the warning on the 2% black disk!

 

I have not tried sanding PTFE, I will do that and include that with the PTFE powder test comparison.

PTFE powder looks black in UVIVF.

 

Added:

Spectralon 99% white disk shown with 52mm filter 'stacker' used as cover.

post-87-0-79020400-1512432649.jpg

 

post-87-0-35062700-1512432656.jpg

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  • 1 month later...

I finally got my Labsphere standards, after they've been around the US, then Amsterdam before me picking them up in Austria (a friend brought them over from the US for me after I bought them at the end of last year). A couple of them have chips in the clear covers, and one cover is missing, and a couple of standards are obviously marked, but I shall have to have a go at cleaning/polishing them. Overall I think that was an ok purchase for just over the price of one new standard from Labsphere :)

post-148-0-60071300-1516721262.jpg

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Jonathan, Indeed, nice kit. Yours are like mine, same size and glass tops. These are different from the type that Andrea has. Hers have the screw on plastic tops.

I think you will be very happy if you do the wet/dry sanding, this will clean them up quite nice if they are dirty, which you will see quite evident with black light.

My kit is only 4, but the same foam and kit size, but with a wooden case. I like your sealed plastic case better.

You should find that the 52mm filter 'stacker' will fit perfectly over the top of these as covers, like I show above, and those don't physically touch the surface of the Spectralon like the glass does.

I have retied the glass circles and use the stacker covers instead.

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Hmm, interesting thanks Steve. I hadn't heard of the 52mm filter stacker caps before but will take a look at them. The box looks good, but it was bashed around a bit in the past and the 2 clips, which are used to hold it closed, have broken off it. So, a large elastic band will have to do the job for the moment (how professional it looks too)....
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Who makes/sells these Spectralon standards? I've never seen these with glass or clear covers or in a foamed box.

 

I did get a Pelican case (as Ulf suggests) for mine shortly after I bought them. :D But Jonathan's foam cutout is much neater looking than my plucked one.

 

Remember that if you are using an uncalibrated set, you cannot be assured of the stated reflectivity. One of mine (I forget just now) varies by 1%, another by 1.5% in the UV area. Of course, if you have a way to measure them yourself throughout the UV/Vis/IR region, then all will be well.

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Jonathan, your disks have a little label on the back of each, with the Spectralon part number on each? Right?

 

Pelican case would be best, but the foam might not fit the same, and the foam that comes with the disks is the best I have ever seen.

The foam can be a mess though, take a look at it with black light, spray wash it, get it clean before you put sanded disks back it.

 

Yeah, I like the stackers because they don't touch the Spectralon surface. They don't stay on, they just sit there and cover the surface.

These are a slightly different diameter than the ones Andrea has, so Labsphere has nothing else that will work. The ones like Andrea has are nicer with the screw on caps.

There might be a way to combine two regular filter ring, with the glass in the middle, stacked, to allow for a cover that is clear, yet doesn't touch the surface.

Have not tried that yet... Would stick up higher though... hmm...let me try that... be back...

 

OK, that will not work, the glass circles are 54mm, so they will not fit inside the 52mm rings.

Best idea I have there is to use a 52mm ring, and glue the glass on the top (being the bottom edge of the back threads) of the ring.

That way you can see what disk is under the hood.

Otherwise, you could label each stacker cap on top.

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Thanks for the link Steve. Yes mine are in a Labsphere plastic case, and have the code number stickers on the rear.

 

At some point Andrea I'll get them measured, but I need to get my measurement system up and running first. Alternatively, if I can get work with someone with a nice Analytical lab, I may, ahem, measure them there....

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