Underwater magnets

Sleepydoc · Dec 11, 2017

I'm thinking of making a holder for my PMUP ATO pump and would like to hold it in place with magnets. Does anyone know of a good/safe way to do this? You can get rare earth magnets at Home Depot, but I don't know if they're necessarily safe to leave under water.

I've thought of boring a shallow hole in the acrylic for the magnet and encasing it in epoxy, but I'm curious what others have done.

Jose H · Dec 12, 2017

Following...I’ve been wanting to get magnets to make some frag racks, magnetic rocks, and wondering the same. P

Salty1962 · Dec 12, 2017

I go to somewhere like K&J Magnetics and purchase @ 25lbs magnets and encase then in acrylic for my applications. It's a pain mixing the acrylic but they workout well. Allot cheaper.

Reef-junky · Dec 12, 2017

Why not just jam some egg crate against the pump to keep it upright?

don_chuwish · Dec 12, 2017

Check your other thread - someone is already making ATO pump holders with embedded magnets.

cromag27 · Dec 12, 2017

Neodymium magnets will rust and leech harmful metals into your water. I make pods out of acrylic with a cnc router. Not too hard if you have the equipment and know how to properly weld acrylic together.

https://octoaquatics.com/octo-pods/

mannyhernz · Dec 12, 2017

cromag27 said:
Neodymium magnets will rust and leech harmful metals into your water. I make pods out of acrylic with a cnc router. Not too hard if you have the equipment and know how to properly weld acrylic together.

https://octoaquatics.com/octo-pods/

Interesting... I like diy'ing my own racks but always have issues with magnets not holding my 50 plug racks...how much weight can that pod handle?

cromag27 · Dec 12, 2017

that really has to do with many factors: weight of the rack with frags, how thick your glass is, how far out the rack sticks out from the tank, the design of the rack and even water flow. if you have a photo of your rack i might be able to take a guess.

mannyhernz said:
Interesting... I like diy'ing my own racks but always have issues with magnets not holding my 50 plug racks...how much weight can that pod handle?

mannyhernz · Dec 12, 2017

cromag27 said:
that really has to do with many factors: weight of the rack with frags, how thick your glass is, how far out the rack sticks out from the tank, the design of the rack and even water flow. if you have a photo of your rack i might be able to take a guess.

Don't have a photo since I'm in the process of making a new one
It's 1/4 acrylic about 15"x8" rectangle
Tank is 12mm thick
Flow is not high, but does get it.
But I make new ones every 6 months because of the magnets.

Rick Mathew · Dec 12, 2017

I coat the ones I use in a 2 part Epoxy....EpoxACast 690 I think it is called...works well....easy to do...and does not seem to detract from the magnets holding power

Rick

Jose H · Dec 12, 2017

cromag27 said:
Neodymium magnets will rust and leech harmful metals into your water. I make pods out of acrylic with a cnc router. Not too hard if you have the equipment and know how to properly weld acrylic together.

https://octoaquatics.com/octo-pods/

What’s the max thickness of glass that these will hold?

cromag27 · Dec 13, 2017

I'd guess three.

mannyhernz said:
Don't have a photo since I'm in the process of making a new one
It's 1/4 acrylic about 15"x8" rectangle
Tank is 12mm thick
Flow is not high, but does get it.
But I make new ones every 6 months because of the magnets.

cromag27 · Dec 13, 2017

Really depends on the load and other values. By themselves I think it's about an inch.

Jose H said:
What’s the max thickness of glass that these will hold?

Jose H · Dec 13, 2017

cromag27 said:
Really depends on the load and other values. By themselves I think it's about an inch.

That’s more than I need and might have to order a few very soon. Thanks.

ispookie666 · Dec 16, 2017

I made one using a magnet coated in epoxy(10kg pull) and then attached it to frag rack using epoxy. I used a 5kg pull magnet on the outside on a 10mm thick glass