wrote:

Are the cheap end versions any good ?

As a general rule, no. However you may get lucky, some of them may be
better than useless.

http://www.tooled-up.com/Product.asp...ensor-0-77-110

Specifically I want to use them to detect studs behind plasterboard
(1930's house) so I can hang shelves, pics
etc.

For ones that definitely will work try the Zircon range. They are not
that cheap but can usually reliably detect a number of things.

Or should I invest in a couple of powerful magnets ?

Magnets can be handy in some cases anyway. Even the best stud detectors
will fail with foil backed plasterboard (or with foil covered insulation
behind s the plasterboard)

(rswww.com do a good range of Zircon scanners)


--
Cheers,

John.

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