Mirror Frame Construction.

[Andy Kev.]

Morning All,

I've got a mirror for the bathroom and want to make a frame for it. A little research has shown that frames typically have a couple of rebates on the rear side; one for the mirror and one for backing which holds the mirror in. It occurs to me that it would be simpler to just groove the frame and hold the mirror in that. Am I right in guessing that rebates are preferred over grooves in case the mirror gets broken because you obviously cannot replace a mirror which is housed in grooves? I'm thinking of using thin ply for the backing and just tacking it in place. Is that a sound method?

I fancy using walnut as the wood (although I'd consider using any wood other than blasted pine). Is walnut suitable for use in the occasionally steamy environment of the bathroom? Out of interest, are there any woods which should not be used in such an environment?

 

[custard]

Morning All,

I've got a mirror for the bathroom and want to make a frame for it. A little research has shown that frames typically have a couple of rebates on the rear side; one for the mirror and one for backing which holds the mirror in. It occurs to me that it would be simpler to just groove the frame and hold the mirror in that. Am I right in guessing that rebates are preferred over grooves in case the mirror gets broken because you obviously cannot replace a mirror which is housed in grooves? I'm thinking of using thin ply for the backing and just tacking it in place. Is that a sound method?

I fancy using walnut as the wood (although I'd consider using any wood other than blasted pine). Is walnut suitable for use in the occasionally steamy environment of the bathroom? Out of interest, are there any woods which should not be used in such an environment?

A rebate is used because you want to be in the position of gluing up and applying a finish without a vulnerable mirror getting in your way. Also, the mirror reflects the interior surface it's resting against, so in quality work you might want to finish this or even paint it matt black, a tricky job with a groove. Finally, it's difficult to get a groove so it's a snug fit, it'll probably be bigger than the mirror which will make it rattly, with a rebate you can get a snug fit using "sprigs" to push the backing against the mirror (use one rebate, or make the mirror rebate shallower than the mirror thickness).

Walnut's fine for bathrooms.

 

[AndyT]

I've only done mirrors using rebates. I can't imagine grooves being easier - with rebates you can get all the assembly and glueing done without the complications of trying to keep a mirror unbroken and free of glue.
The trad way was to make the mirror a loose fit and then wedge it with little bits of wood or leather. I expect most people would use silicone for this nowadays.

A rebate can easily be coloured black before the mirror goes in - this looks better than seeing the bare wood through the edge of the glass.

I have noticed commercial work where a thin mirror is just stuck on plywood which forms the panel of a conventional frame and panel construction - it didn't look as bad as it might have done and I bet most people would never notice.

 

[Trafalgar]

Glass sits in a rebate so that it can be replaced if broken.

 

[Andy Kev.]

Custard and AndyT,

thanks for the replies: rebates it is then!

The reasons you give for that being the right approach are why this forum is so good. It's much more convincing to be doing something when you know what the reasons for it are as opposed to just using a plan which is little more than a set of instructions.

 

[AndyT]

Thanks Andy

As the cogwheels in my mind slowly ground round, I realised it might help to direct you to this thread traditional-mirror-framing-t88530.html !

 

[Seiken]

You may already be aware of this but does the mirror you've got have a foil or film over the silvering? If not its recommended that it's added to stop moisture ingress damaging the silvering when a mirrors used in a damp environment such as a bathroom.

 

[Nelsun]

A very timely thread with some great tips and advice. Guess what I'm making this weekend (homer)

 

[Cheshirechappie]

Joyce also has a section on mounting mirrors; pages 445-447. Nothing in Hooper and Wells, though.

Joyce recommends letting the mirror into a rebate in the frame a little larger all round, and fixing it by pushing in softwood wedges between the side of the rebate and the glass, fixing the wedges with glue and pins, as AndyT mentioned above. The plywood back is then either applied to the frame, or let into a separate small rebate, secured with brass screws, and with a gap between mirror and back-piece. That allows the back to be removed easily should the glass ever need replacing. He also suggests that frames should be of a light section only, since the glass will keep the framework square and rigid, and the plywood back will strengthen the jointing.

One method of construction he gives is to make a frame of squared stock, jointed by either a single dovetail or a mortice and tenon at each corner, then creating the rebate by applying strips (often cross-grained in older work) about 1/8" (3mm) thick to the front, overlapping the inside of the frame by enough to cover the mirror edges.