Have to re-adhere one magnet; should/how to remove adhesive the rest?

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alpharalpha   100 W

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Have to re-adhere one magnet; should/how to remove adhesive the rest?

Post by alpharalpha » Jan 21 2019 7:05am

I have a brush motor that has a loose magnet and I am wondering while I've got it apart (and thinking if one has come loose, probably from inferior adhesive others are going to also) if there is any way to loosen the adhesive and remove the remaining magnets and re-adhere them all?

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Re: Have to re-adhere one magnet; should/how to remove adhesive the rest?

Post by Dauntless » Jan 22 2019 3:04pm

Darn, haven't actually messed with magnet adhesives. Might it be 2 sided tape?

I would think it would not be something with a low forming temperature because you would indeed have trouble with motor heat, but it DID come loose so maybe it does become soft before the temperature of water boiling. Keep in mind that anything that removes it from one side of the casing will loosen the other battery.

Is what's left sticky, coming off? Acetone or citric acid might take it off. I can't see it, no idea how important it might be to remove what's left. I would be concerned that you don't create a thicker layer than was already there and push the magnet closer to the armature.
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alpharalpha   100 W

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Re: Have to re-adhere one magnet; should/how to remove adhesive the rest?

Post by alpharalpha » Jan 23 2019 8:36pm

I found a post on here the person used stripper and it was a very difficult process. But removing the housing for one magnet when by my thinking if it's all the same adhesive if one has come loose than others may also; but it seems that it's easier to remove the old adhesive after the magnet's come loose than it is to remove the adhesive while the magnet's still attached.

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Re: Have to re-adhere one magnet; should/how to remove adhesive the rest?

Post by larsb » Feb 08 2019 12:21pm

I'd leave the remaining magnets alone if there are no obvius flaws to the glue residue from the one that got loose.

A fingerprint is enough to cause the single magnet to come loose, doesn't have to be any problems with the rest of them.
Ride on!

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Farfle   1 MW

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Re: Have to re-adhere one magnet; should/how to remove adhesive the rest?

Post by Farfle » Feb 08 2019 10:46pm

Degrease, lightly hit both surfaces with a maroon scotch brite (the nickel plating on neo magnets is real thin), acetone and then bond. Loctite 331 with activator is my go-to for magnet adhesives.
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alpharalpha   100 W

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Re: Have to re-adhere one magnet; should/how to remove adhesive the rest?

Post by alpharalpha » Feb 09 2019 11:16am

Farfle wrote:
Feb 08 2019 10:46pm
Degrease, lightly hit both surfaces with a maroon scotch brite (the nickel plating on neo magnets is real thin), acetone and then bond. Loctite 331 with activator is my go-to for magnet adhesives.
Thanks for mentioning that about the plating on the magnets. Do you think the Loctite 331 would work better than 3m dp420?

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Re: Have to re-adhere one magnet; should/how to remove adhesive the rest?

Post by larsb » Feb 09 2019 1:37pm

I'd say both are good enough, high temp resistance glues with strength. DP420 seems superior based on the datasheet.

If you don't already have a dispenser gun then I'd still say the 331 is the best since it is single component and you have zero risk for issues caused in the mixing of base and hardener.
Ride on!

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