Metal Back Box Sticks Out

[Eddman]

I have installed some metal back boxes on the side of my very old chimney breast. I chipped away the plaster back to brick but the back boxes still stick out a bit. Can you get narrow back boxes or do i need to chip out some of the brick too?

Chipping out brick sounds messy and tricky!

Eddy

 

[ban-all-sheds]

Boxes come in different depths - don't know what size yours are, nor what size you should be using given what you plan to put in them.

Cutting into brick is standard procedure - use a bolster or scutch chisel. Stitch drilling can be a useful technique.

 

[MarkBarl]

As your chimney breast is old, the bricks will probably be crumbly, I would advocated drilling a pattern in the whole area to the depth you require before carefully removing the required with a bolster, my house has old bricks (1890) I found this is a fairly reliable way of not taking too much away when recessing the back boxes.

 

[Taylortwocities]

You'll need to use whatever depth box is required by whatever you are mounting on it (socket, etc). Dont forget to leave some extra space for the wiring!
Roughly, standard sizes are 25mm, 32mm & 47mm.

 

[Eddman]

i (think) i am using the 25mm ones and the plaster is only 18/20mm in places. I guess i will be drilling/banging with a chisel at the weekend! Do i just repeatedly hit it until bits fall out sufficient to get the box in?

 

[Taylortwocities]

As above, if you just whack at the brick, and the mortar is of a certain age, then you'll loosen the whole brick and you will then have real problems.

Take the existing box out and drill lots of holes in the back, especially round the rear edges of the box. Then carefully chisel out the brick until the hole is deep enough.

See this video, around 1m24s

After all of this, if the brickwork is crumbly, set the back box in some quick set mortar. That will be easier than trying to drill/plug/screw the fixing.

 

[Simon35]

i (think) i am using the 25mm ones and the plaster is only 18/20mm in places. I guess i will be drilling/banging with a chisel at the weekend! Do i just repeatedly hit it until bits fall out sufficient to get the box in?

I usually find working across with a bolster chisel gives you a reasonably flat back surface to your chopped out hole. If your bricks are like those in my 1930's house, you'll find that they are red bricks, easy to chop the surface, and 5-10mm below the surface they have a blue centre, hard as nails to chop out.....so good luck

 

[Eddman]

very helpful video, thanks - i wish i had the thought of looking on youtube now! i have for most other things!!! thanks again everyone

 

[EFLImpudence]

Chisel on a stick.

 

[cjard]

Fit your socket face over the box. The lip on the edge of some faces obscures part of the box. If a few mm of box is still visible, hit the box with a grinder fitted with a flap wheel or grinding disc and shave a few mm off the lip of the box

When fitting the socket, pay attention to routing the wires well. Just stuffing them in in a rats nest mess will probably mean they fold up overlapped and force the socket to stick proud

 

[Iggifer]

Fit your socket face over the box. The lip on the edge of some faces obscures part of the box. If a few mm of box is still visible, hit the box with a grinder fitted with a flap wheel or grinding disc and shave a few mm off the lip of the box

When fitting the socket, pay attention to routing the wires well. Just stuffing them in in a rats nest mess will probably mean they fold up overlapped and force the socket to stick proud

I think grinding 5-7mm off the front of a box is rough as f..k. If it's one or two mm, then maybe. But if you take 7mm off, that leaves you with an 18mm box. Ever tried to fit a single socket to a 16mm knockout?

 

[sparkwright]

I should think grinding 7-5 mm off the front of a knock-out box would probably take off the fixing lugs, and disturb the knock-outs round the edges, and the corners where they fold together, and pretty much render the thing useless.

 

[Iggifer]

Quite. He probably doesn't mean take the whole 7mm off, but unless the OP is using square edge plastic sockets, he'd probably have to chop a pretty decent amount off if his knockout was 7mm proud.

 

[sparkwright]

Very occasionally I have seen double 16 mm metal boxes.

But the only answer here is get the hammer and chissel and do it properly.

Chain drilling round the edge of the box first really does make it very easy.

 

[Iggifer]

I've SEEN double 16mm boxes, I've always assumed they were just for 4 gang lightswitches. I'd never try and squeeze a socket into one.

Try and get an MK USB socket into one of those things!!