Damaged screw-thread

[carregwen]

Thank you all for the interesting suggestions, but I can't stress this enough. I screwed the adaptor to a stout piece of timber and after drilling a hole in the side of the UV (I knew I should have been a surgeon) I hit it really hard with a hammer and pointed tool just like some red-neck in the back-woods might whack a dodgy engine cylinder-head from a Ford pick-up truck after swigging a few Budweisers late at night. It was stuck fast.

PS Do not try this at home.

[Wirefox]

Honestly - when it comes to liquid nitrogen, my advice is to keep a healthy distance away from it

Absolutely. I do not advocate that this is in any way advisable...

[Colin Southern]

Absolutely. I do not advocate that this is in any way advisable...

I remember in my Air Force days they gave us a demo using Liquid Nitrogen as a "safer" substitute for Liquid Oxygen - they dipped a variety of items in it and then dropped them on the floor ... they all shattered like glass. Years later I saw a science teacher pouring it over balloons to get liquid air - without any safety equipment. Have to say, it made me REALLY nervous!

[revi]

I remember in my Air Force days they gave us a demo using Liquid Nitrogen as a "safer" substitute for Liquid Oxygen - they dipped a variety of items in it and then dropped them on the floor ... they all shattered like glass. Years later I saw a science teacher pouring it over balloons to get liquid air - without any safety equipment. Have to say, it made me REALLY nervous!

Liquid nitrogen is fairly common at least in biochemistry labs (handled it myself often enough: grinding plant tissue in a mortar full of liq. N, we did use gloves), and a lot safer than liquid oxygen: you do not want to get a fire started in oxygen-enriched atmosphere

As for that teacher: as long as the kids were kept at a safe distance, that would be darwinism in action... (though the stuff boils away fast, and the boiled-off gas protects what's underneath)

In the case of the filters, the danger would come when handling the frozen metal: skin sticks to the frozen metal and could freeze.

[carregwen]

In the case of the filters, the danger would come when handling the frozen metal: skin sticks to the frozen metal and could freeze.

The hammer method give more satisfaction by the use of brute force. More physics than chemistry!

Next week: How to remove stubborn dust from a camera sensor.

[Colin Southern]

Next week: How to remove stubborn dust from a camera sensor.

One step ahead of you there Rob.

http://images.toolstop.co.uk/product...a0b5bfbfd0.jpg

[carregwen]

One step ahead of you there Rob.

http://images.toolstop.co.uk/product...a0b5bfbfd0.jpg

Don't forget the safety goggles.

[Colin Southern]

Don't forget the safety goggles.

Yep - got em covered thanks.

http://www.thepartyshack.com.au/imag...dnaglasses.gif

[Klickit]

Steaphany - you make an interesting point there about the ambient temperature. I'm very cautious about not over-tightening any filters that I fit, but have often tried to take them off for cleaning and found them much, much tighter, so much so that I thought I would do damage getting them off.

I'm wondering if a smidgen of penetrating oil might unstick stuck filters. Or is that a no-no?

And Colin - I expect to have no trouble identifying you wearing those.

[PopsPhotos]

I've been out for a couple of days, so missed this. A trick we use with rifle scope sights and such is to pop them in the freezer for an hour or two. That almost always works.

Pops