stud / metal detection

[Fred]

Hi,

I finally entered the 21st century and bought an LCD TV. I wanted to fit it to the wall but I had to find a noggin.

I tried using a Zircon stud detector but gave up. I don't think I was steady-handed enough: if I relaxed my grip or pressed too hard, it would set off the detector.

I know people here recommend using magnets to find the plasterboard screws. The walls in this house were built with studs 4' apart, so the plasterboard is only supported at the edges! There were no noggins. I did take the wall apart and add extra studs and noggins some time ago but it seems that I only screwed the plasterboard into the studs, not the noggins, so I had no screws to find!

I was wondering if I ever dismantle any walls ever again, whether to make it easier to locate the studs and noggins by some form of metal detection? I know you can get aluminium tape to put around plastic pipe. If I put this tape over the noggins, would this allow the noggin to detected with a metal detector?

How does metal detection work: is a big thick piece of metal easier to detect that a thin piece of tape? From how far away can this metal tape be detected? through one piece of plasterboard? Through two layers of plasterboard? If used on pipes, can it be detected four inches under a floorboard or is it only good for pipes in notches?

What about aluminium primer paint? If the noggins had a quick coat of that, would that trigger a metal detector?

Thanks.

[Dave Liquorice]

Why not simply mark the floor where they are? Might be covered bya fitted carpet, small notch in the bottom edge of the skirting would be hidden by the carpet.

Noggins are harder.

The basics is a coil that forms part of a tuned circuit of an oscilator. When metal enters the field from the coil it alters the frequency of the oscilation, you either relay that oscilation frequency to a speaker as in the "mine sweeper" type metal detector or just have go/no go indication based on the frequency.

Ferrous metal has a greater effect on the field than non-ferrous. The bigger the bit of metal the bigger the effect as well. Bigger effects are easier to detect.

[John Rumm]

Have you got foil backed plasterboard by any chance? I find my Zircond detector is very good at locating studs unless they are behind foil backed board.

[The Medway Handyman]

I know you can get aluminium tape to put around plastic

The tape is supposed to be placed 'over' the pipes. If placed 'under' plastic pipes behind 12.5mm plasterboard a detector won't pick it up.

DAMHIKTIJD.

[Roger Dewhurst]

There are detectors around that find the wood. I have one.

R

[geraldthehamster]

Why not take photographs of the noggined wall, and also measure where the noggins are? Store photos and measurements together on your computer. All you'll need to do then is meaure in from the edge, and/ or up from the floor, with the photos as a visual reference.

I've just renovated the first floor of my chalet (now dormer) bungalow, and found this approach invaluable when fitting skirting. I took lots of photos of every stage of the work, and am forever referring back to them for things like this.

cheers Richard

[Fred]

Good idea, will do, thanks.

[Fred]

Not as far as I am aware. The walls I have cut into have been "plain" plasterboard so far.

[Fred]

I was wondering about the detection range when using tape, it appears it is quite limited then? Still , it might work with noggins flush with the wall. I wonder whether it would work through a double layer of plasterboard though? I know some people here recommend a double layer for sound insulation.

;)

[Fred]

I have a detector that claims to find wood but that's not quite the same thing ;)

[Fred]

I have tried taking some photos for reference when I do work but sod's law says I get busy and forget to stop and take photos of the noggin/pipe/whatever that I later need.

[NT]

Whats wrong with using a knuckle? Work for me

NT

[PeterC]

But would it hold the weight of the TV?

[Adrian C]

Find a doctor somewhere and borrow their ultrasound baby scanner?

OK, this is DIY. And a rendition of graphics as the above isn't essential. Isn't there a cheap method of establishing the variable density of a material using a sonic wave?

Technical project for someone adapting one of those ultrasonic 'tape measures' perhaps?