Magnets for control cavity cover

[Fishman]

Does anyone have any idea what kind of magnets and what size would be best for this kind of thing

Currently on my build project there is a conventional screw-on cover but I would like something like this for quick access to the battery etc…

http://alpher.co.uk/bass-gallery/

 

[fleabag]

Something like these - they're about 3mm - ish

 

[Grangur]

Someone else with experience in this is @Andyjr1515

[Fishman]

Thanks @Grangur and @fleabag

would the cover itself have something metallic to be grabbed by the magnets, perhaps a thin metallic film?

[Jabba_the_gut]

I recently built a bass with magnetic covers - I used 0.5mm thick magnets in the cover and 3mm magnets in the body. Magnets are readily available on eBay. Here's the build diary for info - I think the magnets are on about page 4.

 

[fleabag]

Yup, Jabba and Andy are thre guys in the know

[MoonBassAlpha]

I doubt you really need anything super strong.

A neat way of doing it would be to arrange the cover so it would pop open when you press on one end of it, kind of pivoting in the middle.

[Andyjr1515]

I think @Jabba_the_gut uses bigger magnets than me, but the ones I use are 5mm in the body and 4mm on the cover itself.  I use first4magnets who have a massive range of sizes, thicknesses, strengths and shapes.

However, note that they are sold also by their pulling power.  The 5mm I use are a 0.26kg pull and the 4mm ones are 0.36kg pull.  I think for a wood cover this is probably the lowest pull to be sure it's going to hold - so maybe go for slightly larger, and/or stronger ones to be sure. 

However, you don't really want super high strength ones because the neodymium magnets are really stupendously powerful and too large and strong can affect the magnetic field of your pickups.

For the truss rod cover I use 3mm at the apex and 2mm at one or both sides in the body,  with 2mm magnets on the cover itself.  The single apex magnet is strong enough to hold the weight of the cover so the side smaller ones are just to hold it in position.

[Andyjr1515]

On 16/04/2019 at 23:04, Fishman said:

Thanks @Grangur and @fleabag

would the cover itself have something metallic to be grabbed by the magnets, perhaps a thin metallic film?

No - it is much more effective to use magnets on the cover and an opposite pole magnet in the body.  Magnet to magnet these tiny things have a huge pull.

[Andyjr1515]

49 minutes ago, Andyjr1515 said:

I think @Jabba_the_gut uses bigger magnets than me, but the ones I use are 5mm in the body and 4mm on the cover itself.  I use first4magnets who have a massive range of sizes, thicknesses, strengths and shapes.

However, note that they are sold also by their pulling power.  The 5mm I use are a 0.26kg pull and the 4mm ones are 0.36kg pull.  I think for a wood cover this is probably the lowest pull to be sure it's going to hold - so maybe go for slightly larger, and/or stronger ones to be sure. 

However, you don't really want super high strength ones because the neodymium magnets are really stupendously powerful and too large and strong can affect the magnetic field of your pickups.

For the truss rod cover I use 3mm at the apex and 2mm at one or both sides in the body,  with 2mm magnets on the cover itself.  The single apex magnet is strong enough to hold the weight of the cover so the side smaller ones are just to hold it in position.

I'd missed @Jabba_the_gut 's reply above and stand corrected.  He doesn't use bigger ones than me.  I reckon the total pull power of our respective size/thickness/strength is probably similar, then

[ped]

Just now, Andyjr1515 said:

 I reckon the total pull power of our respective size/thickness/strength is probably similar, then

Just taking this quote out of context 😂

[Andyjr1515]

Just now, ped said:

Just taking this quote out of context 😂

You see, there are many ways of getting over the Basschat system automatic filth-catcher! . Pink torpedoles?  History, mate 

[Fishman]

Thanks everyone – full report to follow