# Best Epoxy to Use on Project with Rare Earth Magnets



## Deela40 (Dec 11, 2009)

I have been using J-B Weld to attach two rare earth magnets to clothespins to make them into fridge magnets, but the magnets are popping off after roughly 6 months. Does anyone know of a better epoxy that would hold the magnets long term?


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## RichT (Oct 14, 2016)

I use Bob Smith Industries brand and am happy with it. However, I can't say that it would do any better than what you're using. Is there a way to score the back of the magnet, or otherwise make it so there is more of a mechanical bond to it?


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## papadan (Mar 6, 2009)

I use regular 5 minute epoxy, but recess the magnets about 1 /32nd to prevent them from contacting the surface. They hold tight but are easy to pull off without losing the magnets.


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## kelvancra (May 4, 2010)

You did sand the part you are gluing, right?

I've glued panels on using five minute (now I use 2 to 1, 24 hr) to hold panels in place (a hidey hole in a customer's bathroom) and they are still holding six years later.


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## RichT (Oct 14, 2016)

> You did sand the part you are gluing, right?
> 
> - Kelly


I really dislike this sort of reply. It implies that you are stupid if you didn't do something. I suggested the same thing but as just that - a suggestion.


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## bobasaurus (Sep 6, 2009)

I've been using west system g/flex lately and it's really impressive. Long cure time, though. I mix it on a lab scale to get it just right.


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## kelvancra (May 4, 2010)

Richy, first, your response smells of presuming what you wanted it to. Second, your presumption is erroneous. Third, it equates to telling me I'm stupid because I didn't have you play ghost writer and check my wordage to insure it met your, likely, biased standards.

It inspires a suggestion, but the suggestion wouldn't be germane to the matter of holding magnets in place.



> You did sand the part you are gluing, right?
> 
> - Kelly
> 
> ...


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## RobS888 (May 7, 2013)

> Richy, first, your response smells of presuming what you wanted it to. Second, your presumption is erroneous. Third, it equates to telling me I m stupid because I didn t have you play ghost writer and check my wordage to insure it met your, likely, biased standards.
> 
> It inspires a suggestion, but the suggestion wouldn t be germane to the matter of holding magnets in place.
> 
> ...


I agree with Rich (!) on this. It sounds offensive to ask that way when a simple "did you sand first" would have sufficed.

Your response to Rich is offensive as well, perhaps you are having a bad day.

Of course your regular type of response to me, will make all of your responses on this thread offensive.


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## RichT (Oct 14, 2016)

Whatever, Kelly. I see (and it's there in black and white, even in your rude response to me) that you were moved to edit your reply. I'll take credit for that, and I'll give you credit for recognizing your error and making an attempt to fix it.


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## Desert_Woodworker (Jan 28, 2015)

Now here comes Rich- You dislike this!



> You did sand the part you are gluing, right?
> 
> - Kelly
> 
> ...


You are a hypocrite- Here is an example of how Rich Taylor operates and how he attacked me on a Forum- Troll
"I have to say that, at first, your comment pissed me off. It's an affront to Bob Lang as well, for no fault of his own. That you think I'm controlling his "pitch" is very odd indeed. I mention Frank Klausz and Dave Marks frequently too because I admire their work and teachings. Do you think they're in cahoots with me too?
No dude, I'm not pissed at all. In fact I'm concerned about you. Maybe the fidget widgets have messed with your head, but when I saw your rant to vonhagen (whoever that is) on your profile page, I realized you have a problem.
I'm happy to move on. However, I do ask that you leave me out of any future hallucinations that you have. I'm on here to learn and share. Guess what, the next time someone asks for SketchUp advice, I'm going to mention Bob - and I haven't even gotten a free book out of it. I'll be referencing other helpful sources as well.
Take care.
-No matter how much you push the envelope, it'll still be stationery." 
from Rich Taylor


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## Desert_Woodworker (Jan 28, 2015)

Dee- I have not had problems with fridge magnets, but I use "Gorrila glue". You will need to clamp it, due to the expansion of the glue; best to all of us.


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## Desert_Woodworker (Jan 28, 2015)

> Richy, first, your response smells of presuming what you wanted it to. Second, your presumption is erroneous. Third, it equates to telling me I m stupid because I didn t have you play ghost writer and check my wordage to insure it met your, likely, biased standards.
> 
> It inspires a suggestion, but the suggestion wouldn t be germane to the matter of holding magnets in place.
> 
> ...


Don't worry Kelly- this is another "one- project" hot air baloon….


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## Tony_S (Dec 16, 2009)

Simple question….meet complete train wreck…

I've never run into an issue. A quick sand on the back, and whatever epoxy was on hand. Maybe sand the long edges as well and apply more epoxy than you normally would.


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## OnhillWW (Jan 10, 2015)

Another option - Thick CA glue. I use it regularly, faster and safer.


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## waho6o9 (May 6, 2011)

It's wise to sand so the adhesive can take hold.

Now have some fun and make some saw dust…...


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## cc3d (Feb 26, 2012)

While this solution may not work at the scale for your application:

I have done a lot with magnets in wood working and always find a way to adapt this small disc magnets:

https://www.magcraft.com/magcraft-nsn0579?feed=Froogle&gclid=CjwKEAjw1PPJBRDq9dGHivbXmhcSJAATZd_Bgk1i9JyjLOwq7zJGlJ6Y2bR5c3X22civhs_BwmkwuBoC1-fw_wcB

I drill a slightly smaller hole and press these in, no glue. They hold quite tightly and work well.


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## waho6o9 (May 6, 2011)

Nice link Chris, thanks.

Magcraft offers this epoxy for magnets:

https://www.magcraft.com/adhesives


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## cc3d (Feb 26, 2012)

> Nice link Chris, thanks.
> 
> Magcraft offers this epoxy for magnets:
> 
> ...


Thanks for pointing that out. I am gonna try that. In my experience, I have never had anything work well on metal to wood adhesives. It's never a strong bond for me.


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## Deela40 (Dec 11, 2009)

> Simple question….meet complete train wreck…
> 
> I ve never run into an issue. A quick sand on the back, and whatever epoxy was on hand. Maybe sand the long edges as well and apply more epoxy than you normally would.
> 
> - Tony_S


Agreed Tony.

Thanks for the suggestions on sanding all. I think I will try to see how that works.



> While this solution may not work at the scale for your application:
> 
> I have done a lot with magnets in wood working and always find a way to adapt this small disc magnets:
> 
> ...


Thanks for the link Chris. I plan to order these once I run out of my rectangular magnets.


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## SignWave (Feb 2, 2010)

I would expect JB weld to adhere better to the magnets than the wood. Just a guess, but that's based on my experience using it. JB weld sticks to metals well when you prepare the surface well and get it very clean. With wood, less so.

I've made decorative refrigerator magnets and used a regular loctite 5 minute epoxy to hold magnets in place in a recess on the wooden part. Depending on the thickness of the epoxy, you need to adjust the fit. If it's thicker epoxy, then you need a bit more of a gap for it to fill. With a thinner epoxy, you can leave a smaller gap. If it's not sticking to the magnet, scoring the magnet with some fine emery paper will give it more surface area to grab.

Hope these ideas help.


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## kelvancra (May 4, 2010)

Another good point - did the "glue" come off the wood? If it did, a switch to regular epoxy should solve that part of the problem.

As to CA glue, one of the times it's indicated to not be a good choice is, when it's used on a surface subject to vibration and similar abuse. A simple cloths pin for notes, probably, wouldn't suffer too much.



> I would expect JB weld to adhere better to the magnets than the wood. Just a guess, but that s based on my experience using it. JB weld sticks to metals well when you prepare the surface well and get it very clean. With wood, less so.
> - SignWave


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## mitch_56 (Feb 7, 2017)

> It s wise to sand so the adhesive can take hold.
> 
> Now have some fun and make some saw dust…...
> 
> - waho6o9


FWIW, epoxy is not an adhesive, it's a cohesive, so it plays by somewhat different rules
although sanding is still often a good idea when mechanical bonding opportunities are required.

In the OP's application, it looks like he cut small dadoes, and unless those cuts were breathtakingly smooth and glassy, there should have been plenty to grab onto for the epoxy as it cured, even without sanding. It appears from the train wreck above that the magnets were sanded, which is good. It is possible too little was used…in the pictures in the OP, I can't see any epoxy whatsoever, so perhaps only a tiny droplet was used, which presents a couple of possibilities:

1-the epoxy was used in such small quantities (think point of a pin rather than the head of a pin?) that if the OP did a slightly incomplete job of mixing the two components, perhaps this small amount didn't cure properly, and was thus too weak to hold properly

2-because such a small amount was used, if it bonded to a weak area in the wood (perhaps a sliver of wood or drop of sweat interfered with the mechanical bond) then it would give way prematurely

If enough was used, perhaps the epoxy worked well, but the strength of the magnets, pulling against the epoxy, is over time simply tearing off an ultra-thin layer of MDF or whatever material was used to make the clothespins, and thus coming free. So not a failure of the epoxy, but of the clothespin material itself. Perhaps the clothespins are old and splintery, or perhaps sodden with some oil or other agent that would prevent a strong bond?

For the OP, 5-minute epoxy is, generally speaking, the equivalent of buying your tools from Harbor Freight. Don't be surprised if / when it doesn't last. Having said that, even 5-minute epoxy should have no trouble with this application…could it be very old? 5 minute epoxy does have a shelf life, in some cases as little as 18 months…


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## hairy (Sep 23, 2008)

Here's what I use. Never had a problem with it. I've used it on magnets, peppermills and anyplace I need epoxy.

https://www.harborfreight.com/super-strong-quick-drying-epoxy-92665.html


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## kelvancra (May 4, 2010)

In support of Mitch's post, above (i.e., using enough):

I use a lot of epoxy for projects (rather than the five minute stuff, I buy a one and half gallon batch of two to one). Many times, I've put it on wood sparingly and it soaked in, leaving little behind to join to pieces.

For the foregoing reason, I now pre-treat some items with a soak coat of epoxy, or some other penetrating finish. After that hardens, or is VERY tacky and won't flow anymore, I add the final application, which, then, rests on top of the previous coat, rather than soaking in.

Of course, how much it soaks in depends on how dry the wood is, the type of wood, how punky it is, or if it had finish already applied.


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## bigJohninvegas (May 25, 2014)

I use the 5 minute gorilla glue epoxy from the big box store. However, I also have them recessed and use 1/4" round magnets .


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## waho6o9 (May 6, 2011)

Thank you Mitch_56, epoxy is a cohesive.


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## robscastle (May 13, 2012)

I use screws and hot melt glue on my latest project, I know the screws will be OK time will tell on the hot melt glue










Beware of removing or puncturing the chrome plating on rare earth magnets its there for a reason, if you expose the boron to air and it will break down.

I have also tried TitebondIII, CA Glue. multi purpose glue, JB weld and all have failed over time.


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## MrRon (Jul 9, 2009)

How about using plastic clothespins. Epoxy may stick better to plastic.


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