Invisible fixings for removable wall panel: suggestions welcomed

[Bert Coules]

I'm constructing a projection screen which will be semi-permanently mounted: a timber frame fixed to the wall, with a front panel which must be capable of being removed, not often but occasionally. Overall size is 8x4 feet and the main panel will be 5mm foamcore board. This is lighter than an MDF sheet of the same size but not by that much: it's still quite a weighty thing.

Here's a (very) crude drawing:

panel will be supported by the lower ledge and its bottom edge prevented from moving forwards by the raised angle strip but I haven't decided how to fix the panel as a whole. I would prefer no visible fixings, so what are my options? Magnetic catches at strategic points? Magnetic strips/metal strips along the entire other three edges? Velcro? Something I've not thought of?

Any idea will be very welcome. Many thanks.

[Alexander Lamaison]

I'd go for the magnetic catches at strategic points. In the past I've found the 45mm ones here to be very strong:

only knows what the 65mm ones are able to hold. At that price you can afford to experiment.

One note of caution, the screws are *crap* so you'll need some small ones of your own.

Alex

[Bert Coules]

Thanks for that. I've used them, or similar, before though never on something this big and heavy. It will need careful measuring to position the metal plates on the reverse of the main panel (that's one reason I wondered about longer strips) but it should be workable. I don't know, though, how well very short screws will hold in 5mm foamcore: it might be an idea to glue the plates as well (or instead).

It might also be tricky to get the right compromise between a firm adhesion and easy removability. If I use this method, maybe I'll start with just a couple of catches and add them slowly, experimenting with the force of the grip each time.

[Alexander Lamaison]

Good point. I'd forgotten you were using foamcore.

Now that I think about it again, you might struggle to get the board off using these magnets. First of all, how do you get your fingers behind it to lever it? Second, is the foamcore strong enough not to bend at the magnets as you do so ... did I mention the magnets were strong?

Perhaps a better solution would be those catches that release when you push the panel. That way you don't need to get your fingers behind the board at all and you won't strain it as they release gently. You'll still have the problem of how to fix them to the board but I'm sure there's an adhesive to take care of that.

Alex

[The Medway Handyman]

These any good?

[Bert Coules]

Ah, I thought by having a central cutaway in the top and bottom timbers of the frame to create a finger-space behind the panel.

If the magnets are indeed that strong then yes, that could be a problem.

That's an interesting idea. I'll take a look online and see if I can find out the exact configuration: presumably they have to hold the panel a slight distance away from the frame in order to give space for the push-in motion.

[Alexander Lamaison]

An 8mm throw is common:

[Dave Liquorice]

They tend to be quite long, I don't think there is enough depth in the frame. There might be short ones available but you still have the problem of fixing the latchy bit to the foam board.

With the board vertical it won't need much to hold it in place. Think I'd go with short lengths of self adhesive velcro on the frame face/back of board. Degrease the board and timber with lighter fuel or meths before sticking the stuff on.

What might be more of problem is the board tending to bow outwards under it's own weight, even if you fixed it with something all the way round the edge. I suspect that bracing or other support will be required. Bracing could be just bits of 3/4 to 1" square timber glued on vertically. You may also need something horizontal as well. "Adjust on test". B-)

[Jim K]

could Dave's frame for keeping the board flat "nest" into the frame on the wall? perhaps with some sliding pins to retain it (through the sides of the wall frame & into the board's frame) when mounted?

Jim K

[Owain]

I think I'd forget the timber frame, and use a U and a deep inverted U channels, as are used for fixing sliding glass doors into frames.

Metal channel could be fixed up the sides of the foamboard to supply rigidity if it shows signs of slumping its way out of the channels.

of thing

When the panel was removed the only things left on the wall would be the two channels.

You could use both sides of the foamboard for projection, each side masked with a different aspect ratio. Or wallpaper the back side to match the wall, or fit it with whiteboard laminate, to protect the projetcion surface when not in use.

Owain

[Owain]

Also

[harry]

secure to the feet on kitchen work units.

[Bert Coules]

I have considered that, but there are practical snags: even with a central gap in the top and bottom channels there wouldn't be enough clearance behind the panel to hold it while fitting and removing. Sliding doors in U channels are usually fitted by grasping the left and right edges, aren't they? You (or at least I) can't do that with a panel eight feet wide. Channels attached to a timber frame (with matching central gaps) might work, though: thanks for the thought.

I should have said that removing the panel is only necessary in order to get (infrequently) to the wall (and the window in the wall) behind it. It doesn't have to come down for aesthetic reasons.

I'm afraid that you're seriously underestimating the effort and difficulty involved in hefting about (let alone turning round) a panel of that size and weight. Different aspect ratios will be catered for by other means.

Owain

[Bert Coules]

That's too much, I'm afraid. In fact, any clearance would be undesirable: the panel needs to be positioned hard against the frame for rigidity.

[Bert Coules]

I was concerned about that, but experiments so far have suggested that it won't happen, fortunately. I'm reluctant to add anything which will add weight to the panel: even if it only has to come down infrequently, 8x4ft of foamboard is still an appreciable chunk of stuff to be hefting around. Mind you, *lightweight* added rigidity might make it easier rather than harder to handle.

Thanks for replying.

[Bert Coules]

That's a good idea, thanks, as long as the panel's "rigidity" frame doesn't add too much weight to it. I would certainly prefer catches of some sort to anything sticky, whether magnetic or otherwise. Maybe aluminium (or even plastic) angle could be used.

[Bert Coules]

Thanks for the idea, but the more I think about it the more reluctant I am to use anything which would involve having to pull the panel away from some resisting force, whether magnets, catches or anything else. An 8x4ft solid sheet is not something that's easily handled, especially not when it's halfway up a wall.

[Bert Coules]

Thanks for the link, Dave. At first glance I can't quite see how they work but I'll take a proper look.

[Dave Liquorice]

That is a good idea, pins(*) through the wall frame into holes in the rigidity frame. I haven't clue how heavy an 8x4 sheet of 5 mm foamboard is, I wouldn't have thought it was that much, though you said it was about the same as 5 mm MDF, which I do find surprising.

Angle would do instead of square timber, plastic might have to be quite thick and large compared to ali.

(*) Pins = 2" round nails. B-)

[Alexander Lamaison]

How about a thin frame attached to the panel for some rigidity and attach the catch to that. Then that fits inside the main frame with 8mm room for movement at the top.