Jump to content




Photo

Back on the 26D Drag build


  • Please log in to reply
11 replies to this topic

#1 havlicek

havlicek

    OCD Rewinder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 9,882 posts
  • Joined: 20-August 07
  • Gender:Male
  • Location:NY

Posted 06 January 2018 - 09:05 AM

    Last time I did one of these, I got sidetracked/distracted and walked-away from the motor while the magnet epoxy was curing...forgetting to lock them in position.  Naturally, one of the magnets shifted, making the setup useless.  For anyone who isn't sure how well JB Weld holds magnets, I can tell you that...with good prep, getting the magnets out of a can pretty much means destroying them, the can or both.

     This time, I started with a chrome Champion 26D can and end bell.  The can got thinned-out on the four sides to bring it more into the same weight range as the Mabuchi 26D cans.  Having only a single oval hole on the top and no hole on the bottom is a giveaway as to the can's heritage, but it got painted green afterwards, and I installed an adapter and an "actual" can bearing...as opposed to those wannabe bearings Mabuchi used.  :)  

     I shortened another set of those stoopit-strong solid neos and installed them with an Arco magnet shim so that anything magnetic in the same zip code gets stuck to the can.  Even with a still-large air gap, it's really difficult to spin a .560" diameter arm in the setup by hand...like REALLY difficult.

     The end bell is the standard Champion 26D with the pentroof hoods soldered to the brush tubes and a set of spring post sleeves, nothing out of the ordinary.

IMG_2423.JPG

     With this motor intended for drag racing, I wanted to do something as "stoopit" as the magnets.  Then again, I was a little "back and forth" about all this because this is still after all basically a "Mabuchi"  (*well, a Champion, but pretty much the same thing).  In the end, I settled on a "go big or go home" thing and did a reverse-wound a 19/24 in three layers.  By #24awg  standards, 19 turns is a lot of wire and I could easily have gone with fewer turns, but I figure this is appropriate, if you can call any #24awg wound armature "appropriate".  :D

IMG_2424.JPG


  • slotbaker, Chris Stemman, olescratch and 2 others like this
John Havlicek




#2 Kim Lander

Kim Lander

    On The Lead Lap

  • Full Member
  • PipPipPipPip
  • 382 posts
  • Joined: 06-June 09
  • Gender:Male
  • Location:Macon, GA

Posted 06 January 2018 - 09:22 AM

that is beautiful John.


  • havlicek likes this

#3 havlicek

havlicek

    OCD Rewinder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 9,882 posts
  • Joined: 20-August 07
  • Gender:Male
  • Location:NY

Posted 06 January 2018 - 09:37 AM

Many thanks Kim.  Even though I always do my best, I do my bestest with something like this.  The last year or so, I pay even more attention to some details of the epoxying, especially making sure that the outside of the coils are fully saturated behind the back of the crown.  It seems to me that, if the force of a spinning armature is going make things move outward, that's a place to be sure everything is solid!


John Havlicek

#4 Eddie Fleming

Eddie Fleming

    Checkered Flag in Hand

  • Full Member
  • PipPipPipPipPipPip
  • 1,034 posts
  • Joined: 27-April 14
  • Gender:Male
  • Location:Fayetteville, GA

Posted 06 January 2018 - 10:01 AM

Am I correct that the 26D shaft is the same as a 16D?


Eddie Fleming

#5 havlicek

havlicek

    OCD Rewinder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 9,882 posts
  • Joined: 20-August 07
  • Gender:Male
  • Location:NY

Posted 06 January 2018 - 10:23 AM

Am I correct that the 26D shaft is the same as a 16D?

 

Hi Eddie.  Yes, all the Mabuchi and Mabuchi-like (ie: Champion, Johnson etc) motors had 2mm shafts except for the big FT36D.


John Havlicek

#6 Kim Lander

Kim Lander

    On The Lead Lap

  • Full Member
  • PipPipPipPip
  • 382 posts
  • Joined: 06-June 09
  • Gender:Male
  • Location:Macon, GA

Posted 06 January 2018 - 11:16 AM

John...when you epoxy your arms do you apply then cure or do you keep the arm in a SLOW rotation until set....I picked up on that when I had a fishing rod made, they do that to keep the resin from lumping, it worked real well on my arms.



#7 havlicek

havlicek

    OCD Rewinder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 9,882 posts
  • Joined: 20-August 07
  • Gender:Male
  • Location:NY

Posted 06 January 2018 - 11:55 AM

John...when you epoxy your arms do you apply then cure or do you keep the arm in a SLOW rotation until set....I picked up on that when I had a fishing rod made, they do that to keep the resin from lumping, it worked real well on my arms.

 

 

Hi Kim,

     I pre-warm the arm first, then apply the epoxy to one end, stick it back in the oven so the epoxy will flow towards the other end, take it out, flip the arm and apply to the second end making a judgement about how much to apply based on how much ...if any ran to the second end, stick it back in the oven, and then check and flip until the epoxy has gelled and will no longer will run.  In between, I may apply some extra epoxy to areas (*like behind the crown) that I think might need special attention.  Generally, I get full saturation and good results, but it's not the kind of process suited for mass-production obviously.  It's just the best I could come up with!


  • Geary Carrier likes this
John Havlicek

#8 Jesse Gonzales

Jesse Gonzales

    Mid-Pack Racer

  • Subscriber
  • PipPipPip
  • 143 posts
  • Joined: 27-July 17
  • Gender:Male
  • Location:AZ

Posted 06 January 2018 - 05:47 PM

John,

 

use the paint stripper from Home Depot or other like stores. Just immerse the can in the goo and in about 24hrs the mags should just push out, be sure and rinse real good before touching it. makes short work of JB Wekd and others and saves magnets.

 

Jesse



#9 olescratch

olescratch

    olescratch

  • Subscriber
  • PipPipPipPipPip
  • 726 posts
  • Joined: 19-July 13
  • Gender:Male
  • Location:Ravenna, OH

Posted 06 January 2018 - 06:08 PM

John,

 

use the paint stripper from Home Depot or other like stores. Just immerse the can in the goo and in about 24hrs the mags should just push out, be sure and rinse real good before touching it. makes short work of JB Wekd and others and saves magnets.

 

Jesse

This is done without the use of any heat?


John Stewart

#10 Jesse Gonzales

Jesse Gonzales

    Mid-Pack Racer

  • Subscriber
  • PipPipPip
  • 143 posts
  • Joined: 27-July 17
  • Gender:Male
  • Location:AZ

Posted 06 January 2018 - 06:47 PM

no heat at all, neo's don't like heat. for some setups it may take two dunkings plus it leaves the can ready to repaint.



#11 Jesse Gonzales

Jesse Gonzales

    Mid-Pack Racer

  • Subscriber
  • PipPipPip
  • 143 posts
  • Joined: 27-July 17
  • Gender:Male
  • Location:AZ

Posted 06 January 2018 - 09:02 PM

I dropped in at Thorpe about 50 years ago and met John & Gil while there, I saw what looked like a rotisserie made out of an old Stewart Sandwich oven, in it were arms baking while being rotated. Very slick I thought I'd have to build one except my arm production back then didn't warrant it. this was a good way to keep arm epoxy from pooling on either end, as far as I knew only Thorpe had one.

 

Jesse Gonzales


  • havlicek likes this

#12 havlicek

havlicek

    OCD Rewinder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 9,882 posts
  • Joined: 20-August 07
  • Gender:Male
  • Location:NY

Posted 07 January 2018 - 07:41 AM

John,

 

use the paint stripper from Home Depot or other like stores. Just immerse the can in the goo and in about 24hrs the mags should just push out, be sure and rinse real good before touching it. makes short work of JB Wekd and others and saves magnets.

 

Jesse

Interesting Jesse.  I've tried several different paint strippers (several years ago) and got no removal/softening of epoxy.  I may try it again sometime to confirm though...maybe I didn't get "the good stuff".

 

 

no heat at all, neo's don't like heat. for some setups it may take two dunkings plus it leaves the can ready to repaint.

True that the neos generally don't like heat (*actually, no magnet type "likes" heat, the difference is the heat range, and heat can be an effective method for destroying about any common type of permanent magnet, although both ceramics and cobalts tolerate higher heat ranges, and for longer periods, than commonly available neos), they are fine within a certain heat range depending on their grade.  Even the common less-expensive neos are fine at normal motor operating temps which can be between 150F and even as high as 200F.  Warming a neo magnet motor in an oven at those temps or lower shouldn't cause any issues.  ***However, about all neo magnet motors I've seen that have been soldered into a chassis show a measurable decrease in magnet strength on the side that had been soldered, and there can be a difference of 5-10% between the two magnets.

 

I dropped in at Thorpe about 50 years ago and met John & Gil while there, I saw what looked like a rotisserie made out of an old Stewart Sandwich oven, in it were arms baking while being rotated. Very slick I thought I'd have to build one except my arm production back then didn't warrant it. this was a good way to keep arm epoxy from pooling on either end, as far as I knew only Thorpe had one.

 

Jesse Gonzales

 

Yep.  I've long considered doing something like this, but I use a toaster oven for several different things and would have to have one ONLY for arms so I balked.  Vacuum-bagging is of course another way at doing all this, but in the end, just doing a little baby-sitting and flipping works fine.  ***This also allows taking care of issues that can happen before gelling, like catching epoxy that has run over the com!


John Havlicek





Electric Dreams Online Shop