Re-coating a multi-section power resistor

Anyone have any suggestions for re-coating an old power resistor?

The amp I'm rebuilding (a Wurlitzer 661, from the 1930s) has a giant multi-section resistor. All but one of the sections is good, but much of the original coating has flaked away, leaving the coils of wire exposed and vulnerable to damage and short-circuits. I'd like to protect it with an enamel of some type, but I don't know what to use. Naturally it must be non-conductive and heat-resistant. Beyond that, I don't know.

Any knowledge, experience, or wild guesses are welcome. Thanks!

--- Russel Willoughby ---

Russel Willoughby wrote:
Anyone have any suggestions for re-coating an old power resistor?

The amp I'm rebuilding (a Wurlitzer 661, from the 1930s) has a giant multi-section resistor. All but one of the sections is good, but much of the original coating has flaked away, leaving the coils of wire exposed and vulnerable to damage and short-circuits. I'd like to protect it with an enamel of some type, but I don't know what to use. Naturally it must be non-conductive and heat-resistant. Beyond that, I don't know.

Any knowledge, experience, or wild guesses are welcome. Thanks!

--- Russel Willoughby ---

Originally these were coated with a thin ceramic coating - you need find
a suitable glaze and then bake it in a kiln

Remember that the resistor must RADIATE heat away from itself, so the
coating must be thin and not heat insulating.

In my opinion, if the resistor structure is solid, then mount it in such
a way that it is not vulnerable to touching anything and leave it alone
- the wire resistance element shouldn't care about being exposed to the
air unless the atmosphere is corrosive...

John :-#)#

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a way that it is not vulnerable to touching anything and leave it
alone
- the wire resistance element shouldn't care about being exposed to the
air unless the atmosphere is corrosive...


And then you have other problems....

Terry S wrote:
a way that it is not vulnerable to touching anything and leave it
alone
- the wire resistance element shouldn't care about being exposed to the
air unless the atmosphere is corrosive...


And then you have other problems....

Indeed!

John ;-#)#

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(Please post followups or tech enquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

John, thanks for the advice. I could probably get access to a kiln, but the risk/reward ratio for that process seems unfavorable. Anyway, this job is enough work without adding extra steps. I'm going to leave the thing as it is.

--- RW ---

On Jan 21, 12:14*pm, Russel Willoughby
wrote:
Anyone have any suggestions for re-coating an old power resistor?

The amp I'm rebuilding (a Wurlitzer 661, from the 1930s) has a giant multi-section resistor. All but one of the sections is good, but much of the original coating has flaked away, leaving the coils of wire exposed and vulnerable to damage and short-circuits. I'd like to protect it with an enamel of some type, but I don't know what to use. Naturally it must be non-conductive and heat-resistant. Beyond that, I don't know.

Any knowledge, experience, or wild guesses are welcome. Thanks!

* *--- Russel Willoughby ---

You could spray it with high temp engine enamel.

On Jan 21, 12:14*pm, Russel Willoughby
wrote:
Anyone have any suggestions for re-coating an old power resistor?

The amp I'm rebuilding (a Wurlitzer 661, from the 1930s) has a giant multi-section resistor. All but one of the sections is good, but much of the original coating has flaked away, leaving the coils of wire exposed and vulnerable to damage and short-circuits. I'd like to protect it with an enamel of some type, but I don't know what to use. Naturally it must be non-conductive and heat-resistant. Beyond that, I don't know.

Any knowledge, experience, or wild guesses are welcome. Thanks!

* *--- Russel Willoughby ---

Here's another idea -- take it to one of the shops that does custoom
ceramic coating for the car guys. They are always coating their
exhaust systems. I bet they would coat that for you for next to
nothing if you could sneak it in while they are coating parts for
someone else...

Just a thought.

Terry