[Elecraft] Has anyone epoxied their toroids after they were wound?

[J F]

Hi Brian,

Never have epoxied toroids, I can see one major
disadvantage using this method... You'd never be able
to rewind the same core. Epoxy is a real bear to
remove.

I've used hot glue to keep toroids in place, a little
easier to remove if needed.

Think you're better off with nail polish or acrylic..

Cheers,
Julius
n2wn

[Brian Lloyd]

Post by J F
Hi Brian,
Never have epoxied toroids, I can see one major
disadvantage using this method... You'd never be able
to rewind the same core. Epoxy is a real bear to
remove.

Agreed. OTOH, if I built a K2 I don't expect I would ever scrap it
for spare toroids.

Post by J F
I've used hot glue to keep toroids in place, a little
easier to remove if needed.
Think you're better off with nail polish or acrylic..

Good point. Thanks.

My problem is that I have a bias -- I used to live on a boat. I used
West System epoxy for just about every repair as the only two things
that would attack it are UV and fire. Salt water does nothing to it.

73 de Brian, WB6RQN
Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com

[Vic K2VCO]

Post by J F
Never have epoxied toroids, I can see one major
disadvantage using this method... You'd never be able
to rewind the same core. Epoxy is a real bear to
remove.
I've used hot glue to keep toroids in place, a little
easier to remove if needed.
Think you're better off with nail polish or acrylic..

This issue has come up before, and Elecraft has recommended that NOTHING
should be used to hold the turns of toroids together, or glue the toroid
to the board, etc. Nothing is needed and some of the materials used can
have deleterious effects.

Incidentally, the toroid cores are non-conductive and you needn't worry
about insulation being scraped from the wires on the edges of the
toroids causing shorts. In fact, even if you strip the lead too much
and the stripped portion touches the core there will not be a problem,
as long as stripped turns do not contact one another.

So...relax, wind the toroids according to the instructions and don't worry!

[Randy Moore]

OK, so what to the K3 t-shirts at Dayton say?

Randy, KS4L

[Darwin, Keith]

"I went to Dayton to get a K3 but all I got was this shirt".

Just kidding, of course!

- Keith N1AS -
- K2 5411.ssb.100 -

-----Original Message-----
OK, so what to the K3 t-shirts at Dayton say?

Randy, KS4L

[Ron D'Eau Claire]

Note that Elecraft specifically says NOT to attach the toroids to the board
using epoxy, hot glue or any such materials (top of page 54, right column,
of the K2 manual). There is no reason to do so.

The thousands of Elecraft rigs built according to the instructions over the
past decade include many that have bounced along trails in backpacks, been
shaken mercilessly in off-road vehicles, vibrated for hours on end in
aircraft and even accidentally bounced down hillsides on occasion.

Ron AC7AC

[Brian Lloyd]

Post by Ron D'Eau Claire
Note that Elecraft specifically says NOT to attach the toroids to the board
using epoxy, hot glue or any such materials (top of page 54, right column,
of the K2 manual). There is no reason to do so.

I understand and I was not asking about attaching the toroids to the
board. That would make it virtually impossible to replace a toroid
without destroying the board, definitely a "bad thing".

What I was asking about was using epoxy to secure the windings on the
core(s) when the toroid is complete but before attaching the toroid
to the board.

73 de Brian, WB6RQN
Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com

[Stuart Rohre]

Brian, that is also not necessary, and the dielectric constant of an epoxy
coating might shift the resonances of the torroids.

Just wind the turns on with tension maintained as instructed in the manual.

-Stuart
K5KVH

[Ron D'Eau Claire]

Brian wrote:

I understand and I was not asking about attaching the toroids to the
board. That would make it virtually impossible to replace a toroid
without destroying the board, definitely a "bad thing".

What I was asking about was using epoxy to secure the windings on the
core(s) when the toroid is complete but before attaching the toroid
to the board.

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

Understood! That's why I didn't chime in at first. I only intervened when
the thread started drifting to include attaching toroids to the PCB - an
often repeated thread on this reflector!

In all the years I've been winding the toroids (including many Elecraft
products) I've yet to see a winding move. However, in some Elecraft kits
they sometimes recommend "adjusting" the turn spacing on the core to
optimize the circuit after the rig is assembled.

I can't really speak to whether using epoxy would change any electrical
characteristics enough to warrant concern. IIRC Wayne has weighed in saying
not to do it in the past, but I don't have that message handy.

Ron AC7AC

[John, KI6WX]

Applying any material (Q-dope, epoxy, hot glue) to the wound toroid is not a
good idea. It increases the interwinding capacitance and can effect the
performance of the various toroidal transformers. This is especially true
in the transmitter section where the toroids are tuned with a fixed
capacitor to increase the power transfer. The value of these capacitors was
determined without any coating material on the toroid, and changing the
dielectric around the toroid windings may require a change in the
capacitor's value.
-John
KI6WX

Post by J F
Never have epoxied toroids, I can see one major
disadvantage using this method... You'd never be able
to rewind the same core. Epoxy is a real bear to
remove.
I've used hot glue to keep toroids in place, a little
easier to remove if needed.
Think you're better off with nail polish or acrylic..

[peter gerba]

Hi;

See the article below. Roy does some testing with various materials.

I don't seal anything unless it's going to be exposed to the weather.

Pete kn6bi



"Toroidal Inductor Measurements" by Roy Lewallen, W7EL December, 1998


http://www.qrp.pops.net/w7el.htm

-----Original Message-----
From: elecraft-***@mailman.qth.net
[mailto:elecraft-***@mailman.qth.net] On Behalf Of John, KI6WX
Sent: Friday, May 18, 2007 2:34 PM
To: J F; brian-***@lloyd.com; Elecraft Discussion List
Subject: Re: [Elecraft] Has anyone epoxied their toroids after they
werewound?

Applying any material (Q-dope, epoxy, hot glue) to the wound toroid is not a
good idea. It increases the interwinding capacitance and can effect the
performance of the various toroidal transformers. This is especially true
in the transmitter section where the toroids are tuned with a fixed
capacitor to increase the power transfer. The value of these capacitors was
determined without any coating material on the toroid, and changing the
dielectric around the toroid windings may require a change in the
capacitor's value.
-John
KI6WX

Post by J F
Never have epoxied toroids, I can see one major
disadvantage using this method... You'd never be able
to rewind the same core. Epoxy is a real bear to
remove.
I've used hot glue to keep toroids in place, a little
easier to remove if needed.
Think you're better off with nail polish or acrylic..

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[Don Wilhelm]

And to that I would add that is is not necessary.

As validation of that fact,
I built one K2 for a client that has been used mobile in an 18 wheel
truck for at least 2 years. Even with all that shaking and vibration
present in that environment, there were no problems or instabilities -
no fixatives were used at all except for the nylon washer that normally
is used to secure T5.

73,
Don W3FPR

Post by peter gerba
Hi;
See the article below. Roy does some testing with various materials.
I don't seal anything unless it's going to be exposed to the weather.
Pete kn6bi
"Toroidal Inductor Measurements" by Roy Lewallen, W7EL December, 1998
http://www.qrp.pops.net/w7el.htm
-----Original Message-----
Sent: Friday, May 18, 2007 2:34 PM
Subject: Re: [Elecraft] Has anyone epoxied their toroids after they
werewound?
Applying any material (Q-dope, epoxy, hot glue) to the wound toroid is not a
good idea. It increases the interwinding capacitance and can effect the
performance of the various toroidal transformers. This is especially true
in the transmitter section where the toroids are tuned with a fixed
capacitor to increase the power transfer. The value of these capacitors was
determined without any coating material on the toroid, and changing the
dielectric around the toroid windings may require a change in the
capacitor's value.
-John
KI6WX

Post by J F
Never have epoxied toroids, I can see one major
disadvantage using this method... You'd never be able
to rewind the same core. Epoxy is a real bear to
remove.
I've used hot glue to keep toroids in place, a little
easier to remove if needed.
Think you're better off with nail polish or acrylic..

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[Allan Bacon]

I (heart-love) my K3

My other rig is ... FOR SALE

Not kidding, on the shirt I bought!

73
Al
W6GBG

----- Original Message ----
From: Randy Moore <***@comcast.net>
To: Elecraft Discussion List <***@mailman.qth.net>
Sent: Friday, May 18, 2007 11:44:12 AM
Subject: [Elecraft] [K3] T-shirts?


OK, so what to the K3 t-shirts at Dayton say?

Randy, KS4L

[Don Wilhelm]

Folks,

Yes, that is what is on the T-shirt. The "I (heart-love) my K3" part is
on a California auto license plate type image with May and 2007 as the
date stickers.
The "My other rig is ... for sale" part is on the bottom of the 'license
plate holder'.

I hope that gives you a good picture of the shirt - check some of the
photos from tomorrow's Dayton 'events' to see the real thing - it is on
the back and the shirt is gray with black lettering.

73,
Don W3FPR

Post by Allan Bacon
I (heart-love) my K3
My other rig is ... FOR SALE
Not kidding, on the shirt I bought!
73
Al
W6GBG
----- Original Message ----
Sent: Friday, May 18, 2007 11:44:12 AM
Subject: [Elecraft] [K3] T-shirts?
OK, so what to the K3 t-shirts at Dayton say?
Randy, KS4L
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