Magnetic screening for oscilloscope - paractical?

Hi All,
Here's a question that's been knocking around in my head for a while.
I recently bought a Hitachi V1050 'scope - it's a great instrument but, in common with other 'scopes of the same make that I've used, very sensitive to external magnetic fields.
My preveous instrument (an Iwatsu) used to live with my function generator balanced on top of it - if I try the same trick with the Hitach the trace is unusably wobbly.
Now, I'd like to be able to stack equipment in close proximity as I'm quite tight for space, but I'd also like to have confidence that my trace is as flat as possible when grounded. So...

Would it be possible to add any screening/shielding? Of course, mu-metal springs to mind, but I know very little about it besides the name. Is it available to the hobbyist (in the UK), it is affordable, what forms are available, and how it it best worked? Or am I barking up the wrong tree?

This is a [one of many] rainy-day project, but any opinions would be very welcome.

Mu metal can be used for magnetic shielding: https://en.wikipedia.org/wiki/Mu-metal

My Heathkit oscilloscope has a mu-metal shield around most of its picture tube to prevent your problem.

Would the best approach be to shield as close as possible to the tube, to reduce the amount of shielding material required (rather than, say, trying to line the entire inside of the casing with shielding)? Or is placing such a material close to the tube likely to have an effect on the deflection (can't see why it would, but...)?

Maybe I should inspect my old scope to see how that's constructed.

The best advice on that Wikipedia page is on the first line...

"Mu-metal
From Wikipedia, the free encyclopedia
...
Not to be confused with Nu metal."

My Tek scope also has a Mu-metal shield close to the tube. If you put the shield inside the case, there will be other wires and sources of magnetic interference that aren't shielded from the tube. Closer to the tube has the advantage you mention plus it shields locally generated fields.

John

That all makes sense to me...
Thanks for the interest folks.

Thanks canadaelk. I've done the thing I should have done for a start and popped the lid - it does indeed have a cylindrical shield around the neck of the tube and a rectangular box further up where it flares out.
I must admit that balancing gear on top of a scope is bad practice I know, but this does seem more sensitive than my preveous one. I've also got a smaller one of the same series (1020 I think) at work, which seems similarly sensitive and is also very susceptible to the earth's field - moving it around the bench throws the trace rotation way out.

Does anyone have experience of fabricating mu-metal sheilding cans? My metalwork is reasonable, but anealing in an atmosphere of Hydrogen sounds like a bit of a challenge...

A simple heavy steel plate case 1/8' - 3/8" plate around the O scope on 5 sides would make for a considerable magnetic shield.