62 replies to this topic

[gotboostedvr6]

JB Weld is just fine for magnet install. Properly prep can and magnets.

1. Remove or severely score plating on can.
2. Remove old glue from magnets.
3. Clean can and magnets with acetone.
4. Mix JB for at least one minute.
5. Apply glue and let cure 24 hours.
6. Get better with a SCREAMING HOT soldering iron. Use acid and be fast.

[Cheater]

Couple more comments about using JB Weld for securing magnets.

 

First of all, make sure to use JB Weld and not JB Kwik, the five-minute version of JB Weld. The former is much stronger.

 

I applied gentle heat to cure the JB Weld by either placing it next to an incandescent bulb or by sticking the motor can to my Hakko soldering iron's stand while the idling iron was in the stand.

[Bill from NH]

About what temperature would you estimate the light bulb and the idle Hakko provided? I've used oven heat with Koford's black mag glue but have never used JB Weld for magnets.

[Cheater]

Hard to say, Bill. Too hot to handle until they'd cooled for a little while. Guess would be in the high hundreds.

Doesn't take much heat to speed up the cure on an epoxy like JB Weld. IIRC two-three hours was all it took have the epoxy get almost fully cured.

[Bill from NH]

I was just wondering if there was a certain temperature, for a certain length of time that worked best with JB Weld. Rudy Garriga of Slick 7 once had an article online about using JB Weld for bonding magnets, but I question if it still exists.

[Rotorranch]

I used JB Weld sometimes when building motors at my raceway... I'd put it in the toaster at 150F for an hour or so.

 

Rotor

[Bill from NH]

Thanks, Jeff. I had thought if probably would want to be at a lower temperature setting than the Koford black.

[team burrito]

I applied gentle heat to cure the JB Weld by either placing it next to an incandescent bulb or by sticking the motor can to my Hakko soldering iron's stand while the idling iron was in the stand.

 

It works better if you put the Hakko inside the can.

[Dave_12]

I have seen many motors destroyed because of magnets coming loose from the failure of JB Weld. Both D and C-cans.

 

My advise is use Koford magnet epoxy or Skinners magnet epoxy. 
After baking in a oven  zap the magnets

[Cheater]

I did not see that using C-cans, so long as the surfaces were properly cleaned first.

With strap cans, I can believe your advice is very valid.

[Dave_12]

There is nothing in that about matching the magnets or finding the strongest magnet tips. 

[Cheater]

Dave,

 

You should keep in mind that this article was written 25 years ago...

[Bill from NH]

If you have access to a matcher or a gaussmeter, you can do both. My magnet matcher doesn't read directly in gauss but requires a multiplying factor. It hasn't been made in 20 years.

 

I've never seen the need to glue in D-can magnets, A couple drops of CA glue will prevent magnets from sliding back and forth if you use two magnet clips.