Newbie/Outsider question: what are resistors actually made o

[JennaMyria]

Hello everybody!
My name is Myria and I really don't belong into this group at all, but
I do have a question and searching the web doesn't really get me
anywhere, because I guess I lack some basic understanding of
electronics. I was hoping you could help me.
Simple question: What are resistors actually made of? I mean the inside
material. I know it must be some kind of substance that leads
electricity more slowly (hope I phrase that right), but I am interested
in the actual inside materials.
Reason: My husbands grandfather was a radio/TV repair guy from the 50s
to the late 80s and we inherited a huge collection of, well, different
kinds of resistors (and a couple of capacitators). We couldn't sell
them and I was wondering if I could use them in my craft projects. As I
am working with children, I need to know if there is anything inside
those resistors that is inherently dangerous/poisonous like mercury or
maybe lead. And could it be dangerous by contact alone, or if they
swallowed a resistor? (They are not that age group, but the weirdest
things do happen. In todays suing happy society, you cannot be careful
enough!)
Any info is appreciated. Thanks.
Myria

 

[JeffM]

we inherited a huge collection of...resistors
...I was wondering if I could use them in my craft projects.
...there is anything inside...inherently dangerous/poisonous ?
Myria (JennaMyria)

The older resistors were mostly carbon in a ceramic(?) shell.
Randy Day

Carbon composition resistors are a carbon slug inside molded phenolic.

"Bakelite".
Modern film resistors are ceramic INSIDE.
Wirewound resistors (old and new) use ceramics, inside and out.
..
..

The hard shell caps were usually ceramic, too.

Very old ones will have paper cases with beeswax.

..
..

The electrolytic type caps may have some chemicals in them,
but they usually used metal cans as containers.

Yup. Avoid anything that looks like a canister.

 

[JennaMyria]

Thank you all so far! I am however still uncertain.
I do not intend to get the kids into electronis, but I really intend
the stuff to be used in crafts, i.e. glue them to cardboard or make
jewelery out of the stuff!!!
And I am afraid that I don't really know what "phenolic Bakelite" is,
although I will go and google it immediately. I really just want to
know if it is safe to have kids touching those little resistors or
having them wear a piece on a string around their neck.
Thanks, My

 

[Chris]

JennaMyria wrote:

Thank you all so far! I am however still uncertain.
I do not intend to get the kids into electronis, but I really intend
the stuff to be used in crafts, i.e. glue them to cardboard or make
jewelery out of the stuff!!!
And I am afraid that I don't really know what "phenolic Bakelite" is,
although I will go and google it immediately. I really just want to
know if it is safe to have kids touching those little resistors or
having them wear a piece on a string around their neck.
Thanks, My

Hi, Myria. The wires coming out of the resistors almost certainly have
solder coating on them, which is partly lead. If the children are
still small enough to put their hands in their mouths (about 10 to 12
years old, from my experience), they can ingest the lead with possible
long-term health effects. If they're older, please tell them washup is
required immediately after this "craft" stuff.

The other components may have other toxic elements in them, depending
on what you have. Be especially careful with any high voltage sealed
capacitors made more than 25 years ago. These usually look like small
oblong sealed metal cans with two prongs coming out the top. If you
have any of these, you should handle them only with disposable rubber
gloves. Place them in a thick plastic garbage bag, and put the garbage
bag in a box for carrying. Strip off the disposable gloves and put
them in the bag, too. PCBs are absorbed through the skin, and are very
toxic.

Actually, it's probably better to just box the whole works up and drop
it off at a local trade school or junior/technical college that has an
electronics program. As long as you're not looking for a receipt for
tax purposes, and you don't give them any '60s or '70s vintage high
voltage caps, they'll be happy to sort out what they need and chuck the
rest. If you have any of those old HV caps, show them the separate
garbage bag/box combination mentioned above and ask them for advice as
to proper disposal. These may contain PCBs in their dielectric oil,
which causes birth defects and cancer, especially in children.

Good luck
Chris

 

[Chris]

Somehow, I edited out the last paragraph.

It's probably not a good idea to expose kids to old electronics
components in a crafts environment. (Of course, if they're interested
in electronics as a hobby, that's a different story). If you're
thinking about introducing older (13+) kids to low temp tin/lead
soldering (possibly metalcraft or jewelery making skills?) it would
probably be better just to practice with 8 to 24 gauge solid copper
tinned wire. You can strip the insulation off telephone wire or house
wiring wire with a wire stripper, buy a small spool of rosin based
60-40 solder and a soldering iron, and you're good to go. I really
can't think of any other reason to do this that justifies dealing with
lead or the other possible problems. Best just to raise a glass to the
old tech, and then get rid of the stuff where it will do some good and
maybe help somebody learn something. I'll bet that's what he'd want.

Chris

 

[JeffM]

I don't really know what "phenolic Bakelite" is
My (JennaMyria)

The same plastic that PC boards and knobs used to be made of.
Fred Astaire liked dance floors made of the stuff.

Unless the kids have massive oral fixations
and continually suck on the tinned leads (wires with solder on them),
as Fields says, it's no big deal.
Have them wash their hand before you send them home.
(Guessing you already do this.)

Foley specifically mentioned polychlorinated biphenyls (PCBs).
http://www.google.com/images?q=oil-filled-capacitors
Yup. I already said that canisters are to be avoided.