Re: [ATM] VIVA towels protect optical surfaces?

[Mike Lockwood <melockwo@uiuc.edu>]

Hi,

Jeff Rowe wrote:
> My point was to check with the coater. Spectrum has some good
> advice. 3/4 inch thick  plywood and 2X4s might not be necessary
> with  modest sized optics....... Usually ( in my experience) the
> coating folks return the product in the box it was shipped in.
> YMMV. I'd guess Mike Lockwood might chime in. Cheers JR

OK, I'll chime in.

First, on the subject of protecting the optical surface, the coaters I 
have used typically cover the new coating surface with many layers of 
tissue paper, taped tightly across the face and around the side.  The 
important thing here is that the paper CANNOT SHIFT across the face of 
the mirror.  So, if a particle were to be in the paper, it would not 
make a long scratch, it would just abrade a small spot.

I have used kleenex, paper towel, clean soft rags and tissue paper to 
cover (clean) optical surfaces on the way to the coater.  In a pinch, 
a cheap towel costs $5 and it will cushion the surface of a large 
mirror (assuming both are clean).

So far I have not had scratches on the way to or from the coater, and 
that's for ~50 mirrors I have shipped.  Remember, the glass itself is 
far more scratch resistant than a coating.

Doug Hudgins wrote:
>> Consider: I once purchased a 24" mirror from Steve Swayze.  When
>>  Steve finished the mirror, he shipped it to the coater and then
>> they shipped it to me.  They packed it in a cardboard box with a
>> few layers of cardboard padding along the edges and a couple of
>> extra layers of cardboard above and below.  The shipping company
>> (Airborne Express) delivered a box of broken glass to my house.

Ouch.  I never ship finished mirrors in cardboard, though my blanks 
arrive in similar packing from United Lens.  No problems so far (knock 
on wood).

My rule is this - up to ~20" or ~50 lbs, I pack mirrors just like 
Spectrum says, using a cardboard box and foam.  For this class of 
mirror I feel the extra weight of a heavy wood crate will just get the 
package treated rougher, as the handlers assume it can take a beating. 
  I want at least 2" of foam surrounding all parts of the mirror.

Larger and heavier mirrors typically get packed in the same foam, but 
in a wood crate or a cardboard box with wood between the foam and the 
cardboard for extra stiffness and "armor".  For a wood crate you don't 
need 2" of foam above and below the mirror, but I still want that much 
at the edges.

	Mike Lockwood

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