Fast and accurate way to cut plasterboard to match patress boxes - how do *you* do it?

[dom]

Fast and accurate way to cut plasterboard to match patress boxes - how do *you* do it?

Is there a definitive method?

Tried a plasterboard saw (slow, not terribly accurate)

Tried a Fein multimaster with a tatty old blade in it (fast, can be accurate, but too easy to overcut)

With care and patience, any method will be no problem - but I have a lot of them to do, so it's worthwhile to find the *best* way.

I'd prefer to fix the patress boxes on the studs first, measure the loose board with reasonable accuracy, take out a core in the board, in approximately the right place with a holesaw, pull the cables through the hole, fix the board, then trim the plasterboard to match the patress box.

However, I could leave the cables loose, fix the board, cut the holes for the patress boxes (using a template), pull the cables through, then fix the patress boxes through the holes.

What works best?

[John Weston]

To install several Cat5e cable sockets, in a house with plasterboard walls, I've used the Bosch equivalent to the Fein (with a good plunge cut blade that, OK, is now tatty :-) ). I put tape around the blade as a depth marker and was able to cut the plasterboard without cutting the damp proofing membrane on the insulation in the cavity behind. I was able to extract the rectangular cut-outs, with no over-cutting in the corners beyond the lip of the front-inserted plasterboard-wall back box.

Neatest job I've done on a wall for some time... :-)

[Allan Mac]

Save yourself a lot of hassle and use fastfix boxes. Contrary to roumer in some quarters they do not rip out of the wall. Appleby are the best, avoid cheap ones from diy sheds. Get the joiners to bring the cables through the board at the correct height.(some are incapable of doing this!) Cut the backside out of one box to use as a template, offer up box with short sprit level draw around with pencil, cut out hole with plasterboard saw. Some saws have quite a thick blade which can make a rough edge, CK I find the best nice thin sharp blade, makes a nice clean cut. Use some scrap plasterboard to practice cutting holes. Allan

[george [dicegeorge]]

Which of the many bosch PMF blades is best for this job?

it's a fantastic tool, i'v bought one of each blade but only used a few so far (mainly i use it for aggressive sanding and floorboard cutting)

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[JimK]

do you mean dry line boxes or metal boxes already fixed to wall?

mmm is it any good? they cut on the push to avoid tearing the pboard paper "out",

If they have big teeth they cut quicker!

I have an ancient Stanley pboard blade (that you put in a stanley knife handle) but the teeth are small and it gums up quick then bends... the cheapo thick "proper" pboard saw is more accurate and the few large teeth cut quick....

spose if you can't use pboard backboxes (appleby et al) then I suppose that's it... if you *can* use applebys then I would defo use them and avoid all the s*1t you're pondering now...

Cheers JimK

[js.b1]

Tsk.

Angle grinder... with 12" diamond disc obviously... ... what do you mean you don't want 4 two gang outlets... and one in the door... can not please some folk :-)

[John Weston]

I used the HCS plunge cut wood saw as it was one I had available. It's only cardboard and soft plaster it's going through, but the plaster will wear the cutting edge so it's now relegated to plasterboard use only. I'm not sure the metal blade would be better since there is a lot of dust to get away from the cutting edge

[Dave Plowman (News)]

Cutting plasterboard to a pencil line with an ordinary hand padsaw surely isn't a problem? It doesn't have to be mm accurate as the fitting overlaps the cut.

If you are in a hurry, dry lining backing boxes are the easiest type to use - but I personally don't like them since they show behind the fitting

- and look very untidy with some of the newer 'flat plate' metal fittings which stand proud of the wall with them. If you have a stud or whatever behind to fix a metal box to then that makes a neater job. What I do if there's nothing to fix to behind - but it's rather time consuming - is to fix a couple of battens to the back of the plasterboard either side of the metal box and screw into them. You can either glue and clamp them in place until the glue sets or screw through the plasterboard with plasterboard screws and fill the heads. Depending on make, some metal boxes may need additional holes drilled for fixing screws. This method gives an extremely rigid and neat fixing.

[JimK]

yebbut if you fit 'em as intended *before* plastering they "disappear" in the skim coat...

Cheers JimK

[Dave Plowman (News)]

Fine on a new build where things are done in the correct order. ;-)

[JimK]

or in a refurb where new pboard & wiring going in - like the OP.......:>))

JimK

[Dave Plowman (News)]

Assuming you know exactly where you want all the sockets, etc. It's sometimes best to wait a bit and decide on room layout first. Instead of having most behind bits of furniture. But YMMV.

[dom]

Thanks for all the input.

This morning I made up a template in thin ply, single and double patress box cutouts, 450mm and 1100mm off the floor. It's designed to stand on the floor so that the square holes in the board are in exactly the right place for sockets and switches.

Cut plasterboard to size, slap template against board as it's stood where it will go, cut holes with multimaster, slip boxes through holes, and screw to studs, lean board forward and push cables through patress boxes and through holes in board, screw board to studs.

Speed - pretty good (I'll get faster). Results - very neat.

Upsides - absolutely consistent positioning of sockets and switches, and measuring errors eliminated. Downsides are it's a bit fiddly when there's several sockets on the same board.

[JimK]

yup - best to know where sockets are going before starting wiring and

*most definitely* before fixing plasterboard and plastering over it all etc.... erm....??.... ;>)

JimK

[Dave Plowman (News)]

Depends on the house design. I'm used to suspended ordinary wood floors and partition walls so the wiring is done via them - not through the walls. The only room in this house where I've fitted sockets before plastering was the kitchen which has solid brick walls all round, being an extension. And wish now I'd left it till afterwards - despite the additional work ;-)