Which Magnets?

[Twisted_Blenny]

hello im thinking about making a frag rack out of some extra egg crate i've got laying around. was wondering if there are specific magnets i should use that are "reef safe" or would any magnets be ok?

 

[cromag27]

Ceramic are reef safe but aren't strong at all. neodymium are much stronger but not reef safe. I encapsulate them in acrylic to keep water out.

 

[Roberto CRC]

Ceramic are reef safe but aren't strong at all. neodymium are much stronger but not reef safe. I encapsulate them in acrylic to keep water out.

How encapsulate a magnet?

 

[danknuc]

I purchased mine from K&J Magnets, plastic coated and you can choose the strength. http://www.kjmagnetics.com/products.asp?cat=164
I would not go with anything less than 16 lbs strength per magnet. A fellow reefer had tried the epoxy coated ones by he did not like how they held up to the saltwater.

 

[Roberto CRC]

I purchased mine from K&J Magnets, plastic coated and you can choose the strength. http://www.kjmagnetics.com/products.asp?cat=164
I would not go with anything less than 16 lbs strength per magnet. A fellow reefer had tried the epoxy coated ones by he did not like how they held up to the saltwater.

16 lbs? is not much strength to the glass? What thickness of glass do you use?

 

[danknuc]

I have two 75G, so 1/4" or 5/16" I guess. But when you use one on each side and in two or more locations it is plenty for light items, that is why I stated a minimum of 16 lbs. You also have to look at how wide a shelf is going to be, narrow shelves (say 3") require less holding strength than a wide shelf.

 

[Roberto CRC]

I have two 75G, so 1/4" or 5/16" I guess. But when you use one on each side and in two or more locations it is plenty for light items, that is why I stated a minimum of 16 lbs. You also have to look at how wide a shelf is going to be, narrow shelves (say 3") require less holding strength than a wide shelf.

Ok i understand. You could send me a pics of your fraq rack? How many inches are long?

 

[cromag27]

Those small plastic coated magnets have very little pull strength and will most likely not hold up a frag rack, let alone a full frag rack. I have used them for other applications and their strength sucks.

 

[cromag27]

I do it a couple different ways. but I only use acrylic (cut to different shapes) and acrylic solvent.

How encapsulate a magnet?

 

[Mebeknob]

Ceramic are reef safe but aren't strong at all. neodymium are much stronger but not reef safe. I encapsulate them in acrylic to keep water out.

Can you explain why neodymium magnets are not reef safe?

 

[cromag27]

They are nickel and boron. most of the time they are coated, but the coatings contain copper.

 

[Mebeknob]

So you're saying they will leech those elements into the water?

 

[cromag27]

Here are the two most common sizes I use. the large round ones are n52 and will snap your fingers if you're not careful.

 

[cromag27]

Absolutely.

Or the nickel will rust.

So you're saying they will leech those elements into the water?

 

[Mebeknob]

Looks like I need to modify my DIY mag rock [emoji16]

 

[cromag27]

Haha, yeah asap.

 

[radiata]

Stay away from the rubber coated ones. It will take a few years, but the rubber coating will not hold up in salt water.

 

[Mebeknob]

I'm thinking marine epoxy?

 

[cromag27]

Depends on what you're working with and what you're trying to do.

I'm thinking marine epoxy?

 

[mfinn]

I'm thinking marine epoxy?

polyester casting resin seals them up pretty good.
I made a bunch of frag racks 5-6 years ago and used polyester casting resin to coat the magnets and attach them to eggcrate.