> I'm looking for a low cost contact material that can withstand being exposed to unconditioned warehouse conditions for months without the surfaces becoming corroded or oxides.
>
> The shape of these will be similar to D cell batteries with a spring on one side and a flat contact on the other. The device is not a battery but mounts similarly and must work reliable on first install. No jiggling allowed.
>
> The flat contact will mechanically retain a stainless steel spring (304) so this contact metal cannot react with stainless. The spring must be stainless to get the mechanical force we need. No copper or brass here.
>
> My knee jerk reaction is to keep everything the same stainless material. The downside is the battery clip style ones need some bends and shaping that get a little expensive.
>
> The other downside is we the minimum current passing through this contact is 1mA. Not very high to "burn" through oxided layer. We do have 15-30V so that is something but I rather not have to depend on punching through an oxide layer to get contact.
>
> Thoughts are.
>
>
> 1) tinned copper or brass
> 2) Gold plating "LOL too expensive but maybe not in high enough batch sizes"
> 3) nickle plated brass, copper, tin?
> 4) straight tin
> 5) straight nickle
>
>
> Any other contact material/plating options stick out as a winner in this application?
spring copper might work. Strong, can be soldered, doesn't corrode too
bad, no small batch plating needed, good track record for electrical use
etc.
Reply by mike daniels●April 18, 20212021-04-18
On Saturday, April 17, 2021 at 5:50:01 PM UTC-5, mike daniels wrote:
> I'm looking for a low cost contact material that can withstand being exposed to unconditioned warehouse conditions for months without the surfaces becoming corroded or oxides.
>
> The shape of these will be similar to D cell batteries with a spring on one side and a flat contact on the other. The device is not a battery but mounts similarly and must work reliable on first install. No jiggling allowed.
>
> The flat contact will mechanically retain a stainless steel spring (304) so this contact metal cannot react with stainless. The spring must be stainless to get the mechanical force we need. No copper or brass here.
>
> My knee jerk reaction is to keep everything the same stainless material. The downside is the battery clip style ones need some bends and shaping that get a little expensive.
>
> The other downside is we the minimum current passing through this contact is 1mA. Not very high to "burn" through oxided layer. We do have 15-30V so that is something but I rather not have to depend on punching through an oxide layer to get contact.
>
> Thoughts are.
>
>
> 1) tinned copper or brass
> 2) Gold plating "LOL too expensive but maybe not in high enough batch sizes"
> 3) nickle plated brass, copper, tin?
> 4) straight tin
> 5) straight nickle
>
>
> Any other contact material/plating options stick out as a winner in this application?
Its actually 302 stainless not 304. not sure how much of a differnce that makes.
Thanks for the recommendations.
Another constraint I neglected to mention is that the surface should be solderable with typical leadfree (SAC305) type solders and fluxes. No heavy duty fluxes as it could be soldered directly to a PCBA with solder paste.
Reply by Clive Arthur●April 18, 20212021-04-18
On 17/04/2021 23:49, mike daniels wrote:
> I'm looking for a low cost contact material that can withstand being exposed to unconditioned warehouse conditions for months without the surfaces becoming corroded or oxides.
>
> The shape of these will be similar to D cell batteries with a spring on one side and a flat contact on the other. The device is not a battery but mounts similarly and must work reliable on first install. No jiggling allowed.
>
> The flat contact will mechanically retain a stainless steel spring (304) so this contact metal cannot react with stainless. The spring must be stainless to get the mechanical force we need. No copper or brass here.
>
> My knee jerk reaction is to keep everything the same stainless material. The downside is the battery clip style ones need some bends and shaping that get a little expensive.
>
> The other downside is we the minimum current passing through this contact is 1mA. Not very high to "burn" through oxided layer. We do have 15-30V so that is something but I rather not have to depend on punching through an oxide layer to get contact.
>
> Thoughts are.
>
>
> 1) tinned copper or brass
> 2) Gold plating "LOL too expensive but maybe not in high enough batch sizes"
> 3) nickle plated brass, copper, tin?
> 4) straight tin
> 5) straight nickle
>
>
> Any other contact material/plating options stick out as a winner in this application?
>
Mould some silver conductive epoxy onto your SS spring.
--
Cheers
Clive
Reply by Sjouke Burry●April 18, 20212021-04-18
On 18.04.21 1:33, Don Y wrote:
> On 4/17/2021 3:49 PM, mike daniels wrote:
>> I'm looking for a low cost contact material that can withstand being exposed to unconditioned warehouse conditions for months without the surfaces becoming corroded or oxides.
>>
>> The shape of these will be similar to D cell batteries with a spring on one side and a flat contact on the other. The device is not a battery but mounts similarly and must work reliable on first install. No jiggling allowed.
>>
>> The flat contact will mechanically retain a stainless steel spring (304) so this contact metal cannot react with stainless. The spring must be stainless to get the mechanical force we need. No copper or brass here.
>>
>> My knee jerk reaction is to keep everything the same stainless material. The downside is the battery clip style ones need some bends and shaping that get a little expensive.
>>
>> The other downside is we the minimum current passing through this contact is 1mA. Not very high to "burn" through oxided layer. We do have 15-30V so that is something but I rather not have to depend on punching through an oxide layer to get contact.
>>
>> Thoughts are.
>>
>> 1) tinned copper or brass
>> 2) Gold plating "LOL too expensive but maybe not in high enough batch sizes"
>> 3) nickle plated brass, copper, tin?
>> 4) straight tin
>> 5) straight nickle
>>
>> Any other contact material/plating options stick out as a winner in this application?
>
> How about protecting the connection with a sealant?
>
Platina, iridium, osmium, all of them have a very high melting point,
and no erosion/rusting/ , enabling them to survive a lot of sparking.
Reply by Don Y●April 17, 20212021-04-17
On 4/17/2021 4:57 PM, bitrex wrote:
> On 4/17/2021 7:33 PM, Don Y wrote:
>> How about protecting the connection with a sealant?
>>
> My ladyfriend learned the hard way that you don't want to put aluminum valve
> stem covers on the brass valve stems without putting down some fluid film at
> the interface first. Not in New England, anyway. Break out the Dremel...
My "learning experience" was with "Anti-Seize" (TmReg). I will ALWAYS
use it, going forward!
Reply by Joe Gwinn●April 17, 20212021-04-17
On Sat, 17 Apr 2021 15:49:55 -0700 (PDT), mike daniels
<dmcousin2000@gmail.com> wrote:
>I'm looking for a low cost contact material that can withstand being exposed to unconditioned warehouse conditions for months without the surfaces becoming corroded or oxides.
>
>The shape of these will be similar to D cell batteries with a spring on one side and a flat contact on the other. The device is not a battery but mounts similarly and must work reliable on first install. No jiggling allowed.
>
>The flat contact will mechanically retain a stainless steel spring (304) so this contact metal cannot react with stainless. The spring must be stainless to get the mechanical force we need. No copper or brass here.
>
>My knee jerk reaction is to keep everything the same stainless material. The downside is the battery clip style ones need some bends and shaping that get a little expensive.
>
>The other downside is we the minimum current passing through this contact is 1mA. Not very high to "burn" through oxided layer. We do have 15-30V so that is something but I rather not have to depend on punching through an oxide layer to get contact.
>
>Thoughts are.
>
>
>1) tinned copper or brass
>2) Gold plating "LOL too expensive but maybe not in high enough batch sizes"
>3) nickle plated brass, copper, tin?
>4) straight tin
>5) straight nickle
>
>
>Any other contact material/plating options stick out as a winner in this application?
> On 4/17/2021 3:49 PM, mike daniels wrote:
>> I'm looking for a low cost contact material that can withstand being
>> exposed to unconditioned warehouse conditions for months without the
>> surfaces becoming corroded or oxides.
>>
>> The shape of these will be similar to D cell batteries with a spring
>> on one side and a flat contact on the other. The device is not a
>> battery but mounts similarly and must work reliable on first install.
>> No jiggling allowed.
>>
>> The flat contact will mechanically retain a stainless steel spring
>> (304) so this contact metal cannot react with stainless. The spring
>> must be stainless to get the mechanical force we need. No copper or
>> brass here.
>>
>> My knee jerk reaction is to keep everything the same stainless
>> material. The downside is the battery clip style ones need some bends
>> and shaping that get a little expensive.
>>
>> The other downside is we the minimum current passing through this
>> contact is 1mA. Not very high to "burn" through oxided layer. We do
>> have 15-30V so that is something but I rather not have to depend on
>> punching through an oxide layer to get contact.
>>
>> Thoughts are.
>>
>> 1) tinned copper or brass
>> 2) Gold plating "LOL too expensive but maybe not in high enough batch
>> sizes"
>> 3) nickle plated brass, copper, tin?
>> 4) straight tin
>> 5) straight nickle
>>
>> Any other contact material/plating options stick out as a winner in
>> this application?
>
> How about protecting the connection with a sealant?
>
My ladyfriend learned the hard way that you don't want to put aluminum
valve stem covers on the brass valve stems without putting down some
fluid film at the interface first. Not in New England, anyway. Break out
the Dremel...
Reply by bitrex●April 17, 20212021-04-17
On 4/17/2021 7:40 PM, whit3rd wrote:
> On Saturday, April 17, 2021 at 3:50:01 PM UTC-7, dmcous...@gmail.com wrote:
>> I'm looking for a low cost contact material that can withstand being exposed to unconditioned warehouse conditions for months without the surfaces becoming corroded or oxides.
> ...
>> Thoughts are.
>>
>>
>> 1) tinned copper or brass
>> 2) Gold plating "LOL too expensive but maybe not in high enough batch sizes"
>> 3) nickle plated brass, copper, tin?
>> 4) straight tin
>> 5) straight nickle
>
> Bright nickel plate is good, inexpensive, and... do you really want 304 SS for
> a spring? Bronze is just as corrosion resistant, and phosphor bronze is a good
> electric contact material, too. 304 SS can be work hardened, but isn't an optimal spring.
>
If galvanic corrosion with stainless steel is a big concern then brass,
tin, and nickel-silver are out I think.
Straight nickel, cupronickel, phosphor bronze, alloy of nickel and
chrome would be better choices.
But if it's a low moisture/humidity-controlled environment then galvanic
corrosion is not as much of a concern. Stainless steel model train
wheels on nickel-silver track has been a go-to for generations of model
railroaders...
Reply by bitrex●April 17, 20212021-04-17
On 4/17/2021 7:52 PM, bitrex wrote:
> On 4/17/2021 7:40 PM, whit3rd wrote:
>> On Saturday, April 17, 2021 at 3:50:01 PM UTC-7, dmcous...@gmail.com
>> wrote:
>>> I'm looking for a low cost contact material that can withstand being
>>> exposed to unconditioned warehouse conditions for months without the
>>> surfaces becoming corroded or oxides.
>> ...
>>> Thoughts are.
>>>
>>>
>>> 1) tinned copper or brass
>>> 2) Gold plating "LOL too expensive but maybe not in high enough batch
>>> sizes"
>>> 3) nickle plated brass, copper, tin?
>>> 4) straight tin
>>> 5) straight nickle
>>
>> Bright nickel plate is good, inexpensive, and... do you really want
>> 304 SS for
>> a spring? Bronze is just as corrosion resistant, and phosphor bronze
>> is a good
>> electric contact material, too. 304 SS can be work hardened, but
>> isn't an optimal spring.
>>
>
>
> If galvanic corrosion with stainless steel is a big concern then brass,
> tin, and nickel-silver are out I think.
>
> Straight nickel, cupronickel, phosphor bronze, alloy of nickel and
> chrome would be better choices.
>
> But if it's a low moisture/humidity-controlled environment then galvanic
> corrosion is not as much of a concern. Stainless steel model train
> wheels on nickel-silver track has been a go-to for generations of model
> railroaders...
Sorry, meant to respond to the OP.
Reply by ●April 17, 20212021-04-17
mike daniels <dmcousin2000@gmail.com> wrote in
news:e75fff28-34cf-41b5-9e3d-0b624d69d359n@googlegroups.com:
> I'm looking for a low cost contact material that can withstand
> being exposed to unconditioned warehouse conditions for months
> without the surfaces becoming corroded or oxides.
>
> The shape of these will be similar to D cell batteries with a
> spring on one side and a flat contact on the other. The device
> is not a battery but mounts similarly and must work reliable on
> first install. No jiggling allowed.
>
> The flat contact will mechanically retain a stainless steel spring
> (304) so this contact metal cannot react with stainless. The
> spring must be stainless to get the mechanical force we need. No
> copper or brass here.
>
> My knee jerk reaction is to keep everything the same stainless
> material. The downside is the battery clip style ones need some
> bends and shaping that get a little expensive.
>
> The other downside is we the minimum current passing through this
> contact is 1mA. Not very high to "burn" through oxided layer.
> We do have 15-30V so that is something but I rather not have to
> depend on punching through an oxide layer to get contact.
>
> Thoughts are.
>
>
> 1) tinned copper or brass
> 2) Gold plating "LOL too expensive but maybe not in high enough
> batch sizes" 3) nickle plated brass, copper, tin?
> 4) straight tin
> 5) straight nickle
>
>
> Any other contact material/plating options stick out as a winner
> in this application?
>