Subject: Re: Stuck Filters
On Sunday, November 5, 2017 at 3:48:59 AM UTC-5, Savageduck wrote:
> On Nov 5, 2017, Rich A wrote
> (in article<email@example.com>):
> > On Saturday, November 4, 2017 at 7:33:04 PM UTC-4, rwalker wrote:
> > > Haven't checked in here in a long time. Greetings to all the
> > > regulars. I've got a Vivitar cicular polarizer (77 mm) stuck to a
> > > Firecrest IRND 18 sunfilter (77 mm). They seem to have become welded
> > > together. Any advise on how to get them apart. Tried putting on some
> > > heavy duty latex surgical gloves and seeing if that would give me a
> > > better grip, but no use. Any suggestions?.
> > Cast a flat piece of ice in the fringe, put one side of the filter on it for
> > a few minutes. The one filter will shrink as it gets cold and possibly loosen
> > up enough to screw off the other one.
> Think about it. The only area you will be able to get to is going to be the
> outer, or female thread which is trapping the innner, or male thread. Icing
> it will cause contraction, making the connection even tighter.
Wrong. The first filter touching the ice will get colder and contract from the second filter.
Which is why you don't leave it on the ice for a long time. I've done this before and it's worked.
Most recently with a large optical window in an aluminum cell.