epoxy for magnets

teresaq

Active Member
can someone tell me what kind of epoxy to use to cover magnets. I want to attach them to all my powerheads. the ones I found are nickle plated with a 50 to 60 lbs pull rate. they are something like 1.65 each. These have to attach through 1/2 inch glass.
TeresaQ
 

earlybird

Active Member
I never tried nickel plated but a few of us tried the neodynimum (sp?) super magnets that were coated and they just rusted right through. I even tried covering them with a lot of silicone and it still rusted. I did see at a craft store that they have liquid rubber that you can dip things in. There were pictures of dipping metal pliers to form a handle. Might work. Another option is to use glue or silicone and attach to a mag float. Finally, they sell powerhead magnets that are kinda bulky but work really well. Unfortunately they cost $25.
Sorry can't help with the epoxy.
 

marka1620

Member
I've done this on my power heads. Go to lowes or home depot and pick up some Plasti-Dip (spray or dip type). I like the spray as it is easier to use.
Just spray the magnets with the Plasti-dip. Make sure you give several coating and it will work great. Key word.......several coatings. I've had them in my tank for nearly a year with no issues at all.
Best magnets are neodynimum. The things are STRONG. If you are using mags. with a 50-60 lbs pull rate. Be very carefull......they can jump out of your hands and smash the glass.
My mags are 12-14 lbs. rated on 1/4 (I think) thick glass. (47 gallons tank). Two or three of these keep my power heads nice and secure.
 

teresaq

Active Member
There was an earlier thread about mag retros, and someone was covering the magnets with epoxy. I just need to know what kind, or I wonder if the rubber coating would work. I want to redo all my power heads with magnets, but cant if I have to pay 25.00 for each, rather pay 3 bucks and the price to cover them.
TeresaQ
 

teresaq

Active Member
These are the ones I found
Dimensions: 1" dia. x 1/8" thick
Tolerances: ±0.002" x ±0.002"
Material: NdFeB, Grade unknown (N35-N50)
Plating/Coating: Ni-Cu-Ni (Nickel)
Magnetization Direction: Axial (Poles on Flat Ends)
Weight: 0.426 oz. (12.1 g)
Pull Force: 55-65 lbs
Surface Field: 2500-3000 Gauss
Brmax: 11,700-14,500 Gauss
BHmax: 35-50 MGOe
Here is another surplus lot that we happened upon. The grade of these magnets actually varies greatly from one magnet to another. It appears that several production runs of various grades were combined into this one lot. We measured and tested a bunch of them, but the values were all over the board. If all you need is a strong magnet of this size, and grade does not matter, then here is a bargain for you. We are starting with 10,000 of these discs. When they are gone, they are gone for good.
We also stock this size in grade N42 as part number DX02 and in grade N50 as part number DX02-N50.
 

marka1620

Member
The Plasti-Dip has been used and mentioned on these boards. I dries to a fairly hard coating and is water proof. Resists chemicals and won't crack or become brittle.
Not sure about epoxy. A lot more chemicals in that and have to make sure you get a safe one.
 

teresaq

Active Member
I think I will look for the plastic coat.
Do you think those are good to use. my glass is 1/2 inch thick.
TeresaQ
 

marka1620

Member
The higher the grade N42 over N30......the stronger the pull. I have a huge N42 stuck to my fridge. It has something like a 250lbs pull.

Originally Posted by TeresaQ
These are the ones I found
Dimensions: 1" dia. x 1/8" thick
Tolerances: ±0.002" x ±0.002"
Material: NdFeB, Grade unknown (N35-N50)
Plating/Coating: Ni-Cu-Ni (Nickel)
Magnetization Direction: Axial (Poles on Flat Ends)
Weight: 0.426 oz. (12.1 g)
Pull Force: 55-65 lbs
Surface Field: 2500-3000 Gauss
Brmax: 11,700-14,500 Gauss
BHmax: 35-50 MGOe
Here is another surplus lot that we happened upon. The grade of these magnets actually varies greatly from one magnet to another. It appears that several production runs of various grades were combined into this one lot. We measured and tested a bunch of them, but the values were all over the board. If all you need is a strong magnet of this size, and grade does not matter, then here is a bargain for you. We are starting with 10,000 of these discs. When they are gone, they are gone for good.
We also stock this size in grade N42 as part number DX02 and in grade N50 as part number DX02-N50.
 

marka1620

Member
Originally Posted by TeresaQ
I think I will look for the plastic coat.
Do you think those are good to use. my glass is 1/2 inch thick.
TeresaQ
I think you should be fine with those. Seeing how it is 1/2 thick. Just keep in mind when you do place them on the tank and be prepared just in case the one in your hands jumps out. But, seeing how it is 1/2 thick. That should lessen the pull greatly.
If it is stronger than you like. You could also super glue plastic spacers on the ones that will be on the outside of the tank. That would be a very simple fix.
 

marka1620

Member
Your welcome. Another nice feature of the plasi-dip is that it's a non-slip surface which keeps the power heard from sliding on the glass. Epoxy would tend to slide if the pull wasnt enough.
 

al mc

Active Member
I purchased several precoated magnets that I have been happy with. I glued them to the plastic mounting hardware on my maxi jets with superglue and they work very well.
K& J magnets: their part # DC6PC-BLK 3/4" X 3/8" coated magnet
about $3 each
www.kjmagnetics.com
 

marka1620

Member
Originally Posted by Al Mc
I purchased several precoated magnets that I have been happy with. I glued them to the plastic mounting hardware on my maxi jets with superglue and they work very well.
K& J magnets: their part # DC6PC-BLK 3/4" X 3/8" coated magnet
about $3 each
www.kjmagnetics.com

Those look like they are a nice heavy plastic coated mags and would work great as you indicated. I know other sites sell coated mags. but they are very thinly coated and eventually rusted. The ones I bought were thinly coated and didnt want to take a chance. So, I coated them with the plast-dip.
 

joncat24

Active Member
I used the epoxy coated mags from gaussboys.com and after a year in the tank, they were still perfect.
 

earlybird

Active Member
Originally Posted by joncat24
I used the epoxy coated mags from gaussboys.com and after a year in the tank, they were still perfect.
Exactly what I bought twice and all rusted. Maybe a bad batch
Doesn't matter now anyway as I have koralias which have magnet in suction cup.
 
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