Jump to content




Photo

Glyptal instead of expoxy on armatures?


  • Please log in to reply
10 replies to this topic

#1 nzoomed

nzoomed

    Backmarker

  • Full Member
  • PipPip
  • 59 posts
  • Joined: 07-October 18
  • Gender:Male
  • Location:New Zealand

Posted 09 October 2018 - 06:52 PM

Has anyone used this stuff before?

Ive been reading lots of articles here about rewinds and epoxying the armatures, this is something I never used to do, but its been so long since ive worked on any motors in my younger years and I now know much more about this since ive been winding power transformers for amplifiers.

 

Anyway, alot of old guys said they used to use glyptal which was designed for electrical use and is an extremely good insulator, its supposed to dry very quick also.

 

Many people who do transformers just use polyurethane and sometimes use a vacuum chamber to ensure all the air gets out. I dont know many who even use glyptal on transformers these days unless its for high voltage applications, the main reason for using varnish on these transformers seems to be mostly for holding the windings together and stop resonance rather than an electrical insulator.

 

Anyway, im thinking that glyptal would be an excellent choice for small armatures and simply all that is needed is to dip the armature in the stuff and let the excess drip off, i believe its very thin and flows well, to stop the shaft getting coated you would need to tape it or place heatshrink tube over it.

 

One benefit of glyptal is its a great alternative to powder coating an armature and also would keep them looking nice and preventing rust.

 

Any thoughts would be good anyway. Im in the process of sorting out all these old motors ive got in bits, mostly mabuchi 16D and some Hit 1000 motors that need a new lease of life.


Shaun Belcher




#2 havlicek

havlicek

    OCD Rewinder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 10,493 posts
  • Joined: 20-August 07
  • Gender:Male
  • Location:NY

Posted 09 October 2018 - 07:00 PM

The materials used for armatures in slot car motors are pretty specialized.  Epoxy powder needs to be a very good insulator, tough enough to stand up to  tensioning magnet wire, and of course must be heat resistant.  The epoxy used for potting armatures is not the stuff you find in the hardware store...being low-viscosity and having a high heat resistance, up to 500-600F.  This epoxy of course also needs to be strong enough to keep armatures together under the tremendous stress of spinning really fast, oftentimes extremely fast.  It's hard to imagine glyptal being affective as a replacement for either the powder coat or the epoxy...but maybe???


John Havlicek

#3 Jesse Gonzales

Jesse Gonzales

    On The Lead Lap

  • Subscriber
  • PipPipPipPip
  • 225 posts
  • Joined: 27-July 17
  • Gender:Male
  • Location:AZ

Posted 09 October 2018 - 07:33 PM

I tried some red insulating varnish that I got from an alternator shop in my teen years, coated 26D blanks with it. I had to build up on the edges to break the sharp edge. If I recall I never had problems with those 26Ga 26D's with shorts or slinging epoxy. of course that was way back in the day when new 26D's were $3.00 over the counter.

 

Jess



#4 boxerdog

boxerdog

    Race Leader

  • Full Member
  • PipPipPipPipPip
  • 722 posts
  • Joined: 10-November 10
  • Gender:Male
  • Location:Modesto, CA

Posted 09 October 2018 - 07:52 PM

I use Glyptal for sealing the interior of gasoline engines, and it adheres well. But it is hardly "thin", and I don't think it has much strength. To me, it is an old-school enamel that is a good insulator but I wouldn't use it to replace powder coating or epoxy on a slot car arm. 


David Cummerow

#5 nzoomed

nzoomed

    Backmarker

  • Full Member
  • PipPip
  • 59 posts
  • Joined: 07-October 18
  • Gender:Male
  • Location:New Zealand

Posted 09 October 2018 - 11:42 PM

The materials used for armatures in slot car motors are pretty specialized.  Epoxy powder needs to be a very good insulator, tough enough to stand up to  tensioning magnet wire, and of course must be heat resistant.  The epoxy used for potting armatures is not the stuff you find in the hardware store...being low-viscosity and having a high heat resistance, up to 500-600F.  This epoxy of course also needs to be strong enough to keep armatures together under the tremendous stress of spinning really fast, oftentimes extremely fast.  It's hard to imagine glyptal being affective as a replacement for either the powder coat or the epoxy...but maybe???

I know glyptal sticks extremley well to surfaces and people paint it on engines because if the heat.
Looks like it can withstand 266 degrees F, but if nothing else, i think it would be a great alternative to powder coating the armatures, since thats not so easy to do for most people who dont have the setup.

 

Biggest problem is i cant find the epoxy products you have mentioned anywhere available here in New Zealand, so i have to use what I can work with.


Shaun Belcher

#6 nzoomed

nzoomed

    Backmarker

  • Full Member
  • PipPip
  • 59 posts
  • Joined: 07-October 18
  • Gender:Male
  • Location:New Zealand

Posted 09 October 2018 - 11:45 PM

I use Glyptal for sealing the interior of gasoline engines, and it adheres well. But it is hardly "thin", and I don't think it has much strength. To me, it is an old-school enamel that is a good insulator but I wouldn't use it to replace powder coating or epoxy on a slot car arm. 

Yes seems to be very popular on engines, I thought it was rather thin, but the stuff i used years ago might have been thinned down deliberately.

Anyway, I have seen photos of armatures that look like they are coated in some sort of red varnish, so I was assuming it was glyptal.


Shaun Belcher

#7 havlicek

havlicek

    OCD Rewinder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 10,493 posts
  • Joined: 20-August 07
  • Gender:Male
  • Location:NY

Posted 10 October 2018 - 07:43 AM

Hi Shaun,

 

 

 

Looks like it can withstand 266 degrees F, but if nothing else, i think it would be a great alternative to powder coating the armatures, since thats not so easy to do for most people who dont have the setup.

 

The biggest problems with alternative coatings is that they can either be too thick or thin, and not do a good job around the top and bottom "corners" of the stacks, where the magnet wire's coating can easily be damaged causing a short.  You could try using JB Weld, as it's thick enough not to drip, and once cured is very tough.  Even though it has a powdered iron component, it will not conduct electricity and is a good insulator.  Getting a suitably thin-but-even coating will probably take some practice (*junk arms are always a good thing for trying this stuff out), but maybe thinning it out a little and applying it with a small artist's brush can help.  Once cured, it will withstand temperatures much higher than 266F, maybe twice as high.

As for the "setup" to do powder coating, those can be easily home-made, and probably ARE home-made most of the time for slot car motors.  It shouldn't cost more than $20 for an aquarium pump and some plumbing parts to come up with a good one.  People also use these things for powder coating jewelry and fishing lures, and if you look on YouTube for "fluid bed" and/or "powder coating", you should find some easy examples to build.

Alternately, you could try electrostatic powder coating, and Eastwood company sells kits to do this, although they cost some more (*still not crazy-expensive) and coating this way isn't quite as easy or convenient.

***The powders for fluid bed and electrostatic coating are different in some ways, and not necessarily interchangeable.  If you use electrostatic powders in a fluid bed, you can get a very thick coating that isn't suitable for an armature.  Also, most easy-to-find powders for electrostatic coating are polyester and not epoxy.  Those are less durable and far less heat-resistant, but probably as good in either regard as glyptal.

There are some other powder types that might work also, but I have no experience with them.
-------------------------------------------------------------------------------------------------------------------------------------------

For "potting" armatures, some regular epoxies can work fine (with practice) on milder arms, just don't use the "quick-setting" types, as those are even less heat-resistant and on a warm armature won't give you enough time to work...maybe gelling in less than a minute.  It's also possible that the lacquers used for coating coils would be fine for milder winds.  You can probably produce armatures with milder #30 and #29 winds using the above, and also solder the com connections with no problems as well!

---------------------------------------------------------------------------------------------------------------------------------------------

Lastly, always look for possible industrial sources for the epoxy powder and lo-vis/high temp epoxy.  They may not be available generally, but if you meet someone, or maybe know someone who knows someone, it's always possible to get small amounts.  Good luck!


  • nzoomed likes this
John Havlicek

#8 nzoomed

nzoomed

    Backmarker

  • Full Member
  • PipPip
  • 59 posts
  • Joined: 07-October 18
  • Gender:Male
  • Location:New Zealand

Posted 10 October 2018 - 05:23 PM

Thanks John,

 

So basically i just need to find a high temp epoxy (resin?) something that is very thin to apply?

I used an epoxy resin on my tesla coil a few years ago, but that was only one layer of wire on a PVC pipe.

I have a customer who i do work for who runs a paintshop and stocks all sorts of paints, epoxys and glues etc, so it might be worth asking what they have.

 

I will look into the powder coating for sure.

I have a couple of old motors where i see some of the laminations at the bottom have shifted a little clockwise from the rest, im going to rewind it and will align the laminations back up.

 

Does potting and/or powdercoating the armatures typically prevent this from happening again? We are just talking about stock 16D armatures here.


Shaun Belcher

#9 Booger

Booger

    Mid-Pack Racer

  • Full Member
  • PipPipPip
  • 115 posts
  • Joined: 15-June 15
  • Gender:Male
  • Location:SoCal

Posted 10 October 2018 - 09:31 PM

General Electric used Glyptal 1201 on armatures and winding until 1985....Seemed to work OK for them for a long time...But I'm not an engine builder.

 

I don't think it;s for the windings though,just for coating the arm stacks...I"d give it a whirl for that instead of powder coat if need be.

 

I'd look into some type of high temp epoxy for the windings....Something thin or thinable.


Gary "Booger" Baker

#10 havlicek

havlicek

    OCD Rewinder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 10,493 posts
  • Joined: 20-August 07
  • Gender:Male
  • Location:NY

Posted 11 October 2018 - 04:24 AM

 

 

Does potting and/or powdercoating the armatures typically prevent this from happening again? We are just talking about stock 16D armatures here.

 

Either process would help keep the lams in line.  Once the arm is wound, the magnet wire will also keep them in line.  Once done, they won't be going anywhere.  :)


John Havlicek

#11 nzoomed

nzoomed

    Backmarker

  • Full Member
  • PipPip
  • 59 posts
  • Joined: 07-October 18
  • Gender:Male
  • Location:New Zealand

Posted 11 October 2018 - 06:07 AM

 

Either process would help keep the lams in line.  Once the arm is wound, the magnet wire will also keep them in line.  Once done, they won't be going anywhere.  :)

Thats good to know, was expecting that would be the case.

Need to just find some decent products that are easily available here and I should be good to go.

Also need to set up a powder coating rig.


Shaun Belcher





Electric Dreams Online Shop