Electrical Contact Material

Zebra-stripe elastomer conductors would be too "exotic", expensive and would require a lot of redesigning, *if* they would work for what I'm doing.

I might however be able to incorporate wiping if I can determine a good material to use, outside of the contact material itself.(I can make it part of the switching mechanics).

Thanks.

Darren Harris Staten Island, New York.

Good nickel plated brass should do. As an example, for a gas furnace with a millivolt relay, I had problems with a standard "Decora" switch designed for 120V. There was enough surface oxidation to cause an open circuit at such low voltages (about 500mv max) A

12V automotive switch with good wiping and pressure works well. I replaced the Decora switch with another of the same type but with nickel plating and have had no problems since then.

Don Kelly

MOST OF THESE FOOLS ARE ALSO PART IDIOT THEY CANNOT EVEN UNDERSTAND A SIMPLE QUERY FOR A MATERIAL THAT DOES NOT REQUIRE PLATING, SO GO WITH YOUR INSTINCTS. YOU'LL BE BETTER OFF.

PATECUM

My design is complete and satisfactory. Elastomer conductors are exotic for what I want to do and they wouldn't work for me anyway.(And expensive is relative).

All I am trying to settle on is the material for the conductors.

Darren Harris Staten Island, New York.

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Well, unless nickel plating means I'll never have to worry about "dirty" contact problems, I'll stick with Phosphor-Bronze + wiping to keep things clean.

Thanks.

Darren Harris Staten Island, New York.

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And can anyone suggest a material I can use for wiping? (A material that isn't conductive).

Thanks.

Darren Harris Staten Island, New York.

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Charmin

A piece of tinplate (tin-plated steel) cut from the lid of a "tin" can.

You could either use two, or the other contact could be a brass nail.

The action of the movement of the contacts will knock off the oxide when they make contact.

Good Luck! Rich

Usually the contacts are arranged so that they wipe against each other.

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And can anyone suggest a material I can use for wiping? (A material that isn't conductive).

Thanks.

Darren Harris Staten Island, New York.

----------------------------------- Nickel plating so far has gone for over 13 years without a problem while the standard switches lasted under a year. Gold plating works but is expensive As to "wiping" that is a function of the way the contact is made- the contacts rub a bit when closing. This acts to clean them. No need for external wiping with some cloth or emery.

Don Kelly cross out to reply

Contact "wipe" is the term used for how much the contact travel overlaps and is not a material.

After a contact initially touches any further action will cause the contact arm to bend and thus "wipe" or scrape the contact bump against the other contact side bump. This effectively keeps the contact surfaces clean and free of dust specs between the mating surfaces.

For reliable contacts the usual techniques are bifricated (dual arm ends and contact surfaces), dual contacts in parallel, silver or gold (best) contact surfaces, seal them in a dust enclosure or vaccum (best= no dust or oxide), wet them with mercury or other liquid conductor (slow acting) or any of the above in combination. The arms need to be a different material for spring action.

If you want to actaull wipe a contact clean use isopropylene or a good isopropyl alcohiol with low water or oil content and a good lint free cloth wrapped around a contact burning tool, or just a burning tool designed for that usage.

Reed relay contacts are sealed in a vacuum bottle and can be operated via a magnetic field.

Thanks.

Darren Harris Staten Island, New York.

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I don't think that anyone understood what I just asked. But just in case the responders didn't read the entire thread, this is an innovative project.

A) It doesn't yet exist.

B) What is presently commercially available in parts will not be sufficient for my needs.

C) And I'm searching for a good material that can be used for wiping Phosphor-Bronze contacts. A material that is *not* electrically conductive.

Thanks.

Darren Harris Staten Island, New York.

PLATINUM IS YOUR BEST BET....THERE ARE EVAPORATING SOLVENTS YOU CAN USE FOR OFF POWER CLEANSING. FROM THE MIND OF PATECUM :{

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Would you explain how the wiping is to be done?

Searcher7 Inscribed thus:

In that case paper will do what you want ! ie think paper towel.

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Best Regards:
                     Baron.

Paper can leave lint between contacts and cause them to burn. Never use a paper product unless it is certified link free.

Kim-wipes are lint free and we used them on contacts for decades.

"Baron" wrote in message news:igsfhg$3f1$ snipped-for-privacy@news.eternal-september.org... In that case paper will do what you want ! ie think paper towel.

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Best Regards:
                     Baron.

In English, "burnishing."

Cheers! Rich

Wiping as in cleaning?

Crocus cloth.

Cheers! Rich

Sigh... Obviously this has become useless, so I'll just have to try a hard serrated plastic or similar material.

Thanks.

Darren Harris Staten Island, New York.