Magnet Question, Answer Needed Asap

[Calpol]

I have a wood sample board (no picture though!) which I'm looking to wall mount. It's basically a block of Iroko with a big old deep mortice routed out which the samples sit inside between shelf pegs. The samples are about 250 x 200mm or thereabouts.

Anyway I'm planning to hold them in with rare earth magnets so they don't fall out but can be removed. The plan is to use a magnet on the rack and on the samples so they're well and truly held in there.

Enough writing, my question is how should I stick the magnets to the samples and the rack? Obviously CSK magnets are handy but the poles will be the same if they're both screwed in... How about good ol' Araldite?

Could do with ordering them tonight so if you could reply by about 10 that's be fantastic

Thanks a'body

 

[jasonB]

You really only need one magnet and a metal disc, just a slice of a mild steel bar will do. And I'd stick them into a hole with araldite, you could even recess them and glue a bit of veneer cut from the same sample over the top.

Jason

 

[srp]

Do you need 2 magnets? How about a csk magnet on one component and a csk steel screw in the other?

 

[yetloh]

I agree with the other replies; you only need one magnet and a csk screw. A 10mm magnet will be plenty strong enough. Epoxy or superglue will work fine.

Jim

 

[moz]

I use 10mm diameter rare earth magnets (like the ones you get at Axminster) and drill a hole with a 10mm forstner for a snug fit and glue them in with 10 minute, two part epoxy http://www.axminster.co.uk/zap-z-poxy-e ... prod23719/ You could substitute a steel disk for one, it depends on how much security you need. When I use them for door catches, I drill a little deeper and glue on a shallow, matching plug to cover it in which case having two magnets overcomes any loss of hold because of the small separation.

John

 

[p111dom]

Why rare earth magnets? For this purpose I would have thought they would be a little stong unless the samples are quite large. Personally I'd use magnetic sheet. You can buy it in A4 singles in various thicknesses. It has a self adhesive back, it is rubbery and easy to cut with a craft knife. When the samples are off the board, I think the back would look better too.

 

[9fingers]

If you go down the route of two magnets, then remember they are polarised N and S. You need to make sure all the magnets on the board are fitted one way round and all the ones in the sample are fitted the other way round.

Like poles repel, opposite poles attract.

Using one magnet and one steel disc will avoid any such mistakes.

Bob

 

[p111dom]

Thats true but I should have said that you can get magnetised and none magnatised sheets so one of each would do the trick. I used some to attach engraving plates to a trophy base I made for someone. The trophy was laser etched crystal and very expensive. They didn't want to send the whole thing off every year so I used this sheeting to make the plates removable. That way only the plates themselves need to go off for engraving.

 

[9fingers]

My comments about polarisation was mainly aimed at rare earth or other button magnets that have poles on opposite circular faces.

Not sure about the pole location on the fleximagnet sheets - I'll have to play with SWMBO's fridge magnet collection.

Bob

 

[Calpol]

Well, decided to play safe and get two 20x3mm magnets for each block, and it still isn't strong enough! Don't have enough to put another row on each sample and the display but it needs it... Useful to know if anyone's ever in the same position :lol:

Thanks for the help folks

 

[9fingers]

I think the problem is that the magnetic force is acting at right angles to gravity in your application and the magnetic attraction is not strong in shear with respect to the pole axis.

If you sample board has say screw eyes fitted to it and the magnets were in the top face of the sample, I think it would work ok and only one magnet per sample.

Bob

 

[Jacob]

Velcro.

 

[9fingers]

Velcro.

Oh stop being so bl00dy practical Jacob :lol:

Bob

 

[Calpol]

You're probably right 9fingers, we thought they'd be plenty strong but like you say, gravity, and obviously the leverage from a 150mm sample makes it much easier to remove...

Not a fan of velcro G, or should I say 'hook and look fasteners', the noise does my crust in! Magnets are the way forward in every aspect of life!