In article , "Michael A. Terrell"
writes:

David Forsyth wrote:

Double Cotton-Covered ("D.C.C.") Do they still make this stuff? I would
like to obtain some for winding RF coils for homebrew radio receivers.
Anybody know of a supplier or maybe have some on hand?

thanks,

Dave

Both belden and Alpha made it, so I would start with Newark, Allied, or
another large OEM distributor. Also, see if there is a motor rewinding
shop in your area that might use it on small motors. You might pick up a
partial spool at a decent price.

I don't think that Belden or Alpha has made that kind of wire for at
least 2 decades. Got both of their big factory catalogs here and
all I find is "magnet wire" in either light or heavy (two coat) plastic
insulation. My new Mouser catalog has only part of two pages
with "magnet wire," both being the equivalent to old "enamel
covered coil wire." Might try the search engine at Digi-Key, but I
doubt there will be any success.

Last I was at a place that rewound electric motors was 8 years
ago and they had only heavy plastic covered "magnet wire."

The old cotton-coverd coil wire was okay 4 to 5 decades ago but
doesn't offer much for coil building except for the cotton insulation
being excellent to absorb shellac that will dry and hold everything
together very nicely. Actually, back in the old days, a ceresin wax
application was more likely to be applied...dried quicker and moved
the product through production faster. I happen to like McCloskey
"Gym-Seal" floor varnish to coat home-wound inductors, solenoidal
to toroidal...it's all petroleum-based, not a polyurethane, and doesn't
come loose in high moisture environments like some polyurethanes.
"Gym-Seal" seems to stick to polyester and polyamide magnet
wire coatings very well.

There's a slight difference in distributed capacity between DCC and
enameled wire, DCC usually being slightly less (any coating applied
over it will change that to not less). Not enough distributed capacity
to worry about in my estimation.

There's a slight difference in inductance for a given coil form dimension
between DCC and enamel-covered, the DCC having slightly less for
the same number of turns. Again, not enough to worry about.

Len Anderson
retired (from regular hours) electronic engineer person