Re: shielding

On Dec 1, 8:36 pm, "SotR" <fli...@xxxxxxx> wrote:

My question is, what is the desired thickness for copper shielding of a
bass? I understand the aspects of the copper being "workable" so I don't
need a tutorial on that. But I want to make sure it is thick enough to be
effective. And if I were to buy from this site, since .004 is what Carvin
sells, would .003 or .005 be preferable? I see for instance the DiMarzio kit
does not state a thickness.

The "desired" thickness is probably as thin as you can find such as
the stew-mac stuff. My personal choice is the rolls of copper foil
you get at Hobby Lobby stores designed for embossing crafts. It comes
in .003 and .005 and while both work the thinner is better. The reason
is that any of it shields fine but the thinner stuff molds to cavity
shapes better. The Hobby Lobby foil is relatively cheap and readily
available without a hassle.

There is more to it than this. You also want to have the foil stick in
the cavities. If you get the Carvin kits (I've used them and they are
pretty nice) the foil is glued on one side so it sticks in the
cavities or where you put it. When you use the hobby Lobby foil you
also have to buy a can of spray adhesive. This is made by Scotch
(spray-mount) or Borden or Krylon. Basically it's the goo you find on
mystic mending tape in a can. Even smells like the tape. You just
spray it on one side of the foil and let it try. It turns the foil
into a copper mending tape and sticks the copper where you want it.

And finally you'll need to have a soldering iron and solder. I find
it easier to cut a bottom for a given cavity and then stick a long
strip around the sides to form a shield "box" You then have to solder
a bead around the seam between the sides and bottom of your box. It
doesn't have to be perfect, but it does need connections around the
whole perimeter to prevent ground loops. In fact you usually have to
assemble your shield out of several pieces of copper so the individual
pieces must be soldered together to insure good ground connections.

I will say that I believe the Stew-Mac (or some brand) comes with
"conductive" glue. This supposedly allows you to simply stick the
copper in place without soldering the individual pieces. I've never
tried it but people tell me it works great. personally I'm a bit
skeptical about just how "conductive" glue can be made. It sure can't
be as good as a nice solder joint! And I worry about what happens to
the joints as the glue gets old too. But it would save some work.

I shielded my Jazz and it made a difference although it really didn't
have hum problems to begin with. Be sure that you get foil up under
the pickups too! Usually that is the area that makers seem to scrimp
on shielding! Whether or not you can make a "box" around a pickup
depends on the routing on the instrument. I forget exactly what I did
with my Jazz but the idea is to get as much copper around everything
as you can! That is top and bottom. Any open space is an invitation
for hum and noise to find a way in.
And also be sure the pickup wires are shielded too. If they don't
already have shielded wire put braided copper over the wire bundle or
roll a nice copper tube you can put around the wires. Don't forget to
ground the wire shields at both ends. Often for some odd reason a bass
cavity will be wonderfully shielded and then the makers just run bare
wires half way across the bass to the pickups. Talk about a hum
antenna! Duh!

Good luck!

.

Relevant Pages

  • Re: Copper hum shielding.
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  • Copper hum shielding.
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