BLUM hinge question

[rdpx]

Hi there,

I am making a mirrored door for a recess in a bathroom wall that I want to turn into a cabinet and I have a question about concealed hinges.

The hinge I want to use has a boss depth of 12.6mm and it says to drill the 35mm hole to a depth of 12.7mm.

Now I want to keep the door as thin as possible, and I was hoping to use 12mm ply or HDF, and have a 4mm mirror glued to the front. This would give me a door profile of c.17mm

I am wondering if it would be possible to drill the boss hole right through the 12mm door, and then fit the hinges which would then protrude through by 0.6mm. I would then stick the mirror onto the front of the door, using enough gear so that the adhesive layer was about 1mm thick, which would seem to provide enough space for the protruding hinge bosses.

The door is going to be about 900mm x 460mm, and I am thinking that if I use 3 hinges that this should provide enough strength to hold it all.

I suppose my question is about where the stresses are with BLUM hinges - is it the sides of the circular boss that take the strain, or is the flat circle surface of the boss integral to how these hinges work.

Picture attached for clarity - any help would be appreciated.

[I also had the idea of simply using a double sided mirror as a door using the BLUM Cristallo hinges. This would look great as it would just look like a mirror was attached to the wall - but am worried that this might be fragile and also the quote I got was around the £200 mark for the glass & hinges, which seemed kind of steep]

Thank you

Robert

 

[rdpx]

~bump~

 

[mailee]

Any reason for using 12mm ? Personally I would use 18mm with three hinges. I made a bathroom cabinet which was 800 x 400 and used 18mm MDF with a bevelled mirror bonded on and only used two hinges on that. HTH. :wink:

 

[Eric The Viking]

Any reason for using 12mm ? Personally I would use 18mm with three hinges. I made a bathroom cabinet which was 800 x 400 and used 18mm MDF with a bevelled mirror bonded on and only used two hinges on that. HTH. :wink:

I've done exactly that.

One cupboard is 6ft tall and split at waist height into two doors. It's from B+Q's cheap kitchen range, with the plain 18mm doors reversed (to give a flat surface) and with the mirrors bonded onto the flat sides. I drilled the 35mm holes right through, IIRC using the original holes to guide the Forstner-style bit. It worked a treat.

The second one is in another bathroom. It's about 4'6" tall, in one piece. That has rising butt hinges and a Blum soft-closing piston next to the magnetic catch. The MDF has heavy softwood "lippings" on both sides (2x2 for the hinges and 1x2 for the mag catch), which improves the rigidity - rebated for the MDF, which is glued and biscuited-in.

In both cases the doors were 18mm MDF, but one was 'Formica' skinned in manufacture and the other bare, non-MR MDF, primed both sides and edges with dilute PVA.

I had the mirrors (4mm toughened, IIRC) cut to size , linished and stuck on by a local glazier who specialises in mirrors. There's a special glue, but I strongly recommend having it done (then, if they drop off you have someone to complain to!).

One's been in service for about 10 years, the other about six or seven. No sign of the mirrors or hinges shifting from where they should be.

I used one of these:

It's described as a 'hinge boring bit'. I bought it for doing Yale locks years ago, and I like it because (a) it's easy to sharpen), and (b) it doesn't tend to lift the edges of the hole in MDF, like my cheapo Forstners do. It's almost impossible to get doors that size into my drill press (floor standing), so I used a hand drill with a jig that holds it perpendicular to the board (clamped-on, IIRC). You can pilot the hole with a 3mm twist drill too - helps it stay aligned until the 35mm perimeter is cutting well.

I did seal the inside of the holes with PVA, just in case, and the through holes don't seem to have caused any problems at all.

HTH,

E.

 

[rdpx]

Brilliant Thanks Eric that is exactly what I was after - someone who had done it without disaster!

Mailee - I suppose thicker MDF would be next step, but I am wanting to keep the door/mirror as flush to the wall as possible.

Thanks

Robert

 

[Newbie_Neil]

Hi Robert,

Brilliant Thanks Eric that is exactly what I was after - someone who had done it without disaster!

If I've read it correctly, Eric was using 18mm doors and not the 12mm that you are looking to use.

Neil

 

[Chrispy]

I bit that would concern me is getting a good fixing into something only 12mm thick these hinges usually need screwing on as well as the 35mm hole.
if you solve that problem and do go with this you could use a double sided mirror tape they are about 2mm thick (fix tape vertically).

 

[Fergal]

I've done exactly this using 12mm MDF for a mirrored cupboard in my ensuite. The mirrors were approx 900 x 450 x 4 mm glued on with mirror adhesive. Two hinges per door, and I added a length of aluminium angle along the bottom edge to act as a handle as I didn't want to drill holes in the mirrors.

Fergal

 

[Eric The Viking]

If I've read it correctly, Eric was using 18mm doors and not the 12mm that you are looking to use.

Spot on: MDF - 18mm, Glass - 4mm I wouldn't use less because it risks cracking the glass with the shock wave of a slammed door (and 4mm is the minimum for glass in/on doors, IIRC).

I used thick softwood reinforcements down the edges of the bigger door to make it even more rigid. That one closes onto the glass side (it's in a wall, not on a cupboard), so I didn't want to risk it. So far, no problems, but a couple of scares when a draught has blown through while it's closing (it opens into an attic, where normally the skylight /vent isn't open, but in the summer...).

That said, all three doors have large panels cut out to reduce weight. The glueing surface is about 5" wide all round the outside, with a central 'rail' of similar width left on the smaller doors, and two 'rails' on the larger one. It reduces the mass without compromising the rigidity much.

I drilled through for the hinges because it guaranteed alignment - the holes are close to an edge and were pre-drilled for the door by the manufacturer. I measured and was confident I could flip the door vertically, but didn't want to mess it up. It worked.

The thin wood behind the bottom of the 35mm hole doesn't do much structurally, I think, as most of the force is vertical, but the upper hinge (if only two) will want to split out from the side of the MDF. I didn't, but I guess that, if you're worried, you could reinforce the MDF with a loose tenon/spline glued into a kerf cut in through the edge (I've done similar with my biscuit jointer in the past - works well on a big flat bench).

E.