Electrical Engineering - Joining stainless steel "bus"

Author

Joining stainless steel "bus"

Palindr☻me

2006-05-21, 1:21 pm

Hi,

I have a small ceramics oven to repair. The fault was easy to find, one
of the internal conductors has a break in it, where it has been folded
over itself to make a right angle turn.

The problem is, what is the best way to join two stainless steel strips,
each about 1/4" wide by maybe 15 thou thick? They look very similar to
the strips used in battery packs to interconnect cells.

I was thinking of one or two spot welds. Or maybe braze them, although I
haven't researched what rod and flux to use. I have a TIG set, but its
lowest setting is 50A and there wouldn't be much strip left..

Any thoughts? The strip is only handling 2-3Amps, so it isn't going to
be too critical, getting the lowest resistance join possible.. But it
probably gets to a few hundred degrees, so soldering it is probably not
a good idea..

--
Sue

TimPerry

2006-05-21, 2:21 pm

"Palindr?me" <me9@privacy.net> wrote in message
news:1271338htiao2e7@corp.supernews.com...
> Hi,
>
> I have a small ceramics oven to repair. The fault was easy to find, one
> of the internal conductors has a break in it, where it has been folded
> over itself to make a right angle turn.
>
> The problem is, what is the best way to join two stainless steel strips,
> each about 1/4" wide by maybe 15 thou thick? They look very similar to
> the strips used in battery packs to interconnect cells.
>
> I was thinking of one or two spot welds. Or maybe braze them, although I
> haven't researched what rod and flux to use. I have a TIG set, but its
> lowest setting is 50A and there wouldn't be much strip left..
>
> Any thoughts? The strip is only handling 2-3Amps, so it isn't going to
> be too critical, getting the lowest resistance join possible.. But it
> probably gets to a few hundred degrees, so soldering it is probably not
> a good idea..
>
> --
> Sue

drill hole in strip. use stainless nut and bolt to clamp.

Andrew Gabriel

2006-05-21, 4:21 pm

In article <1271338htiao2e7@corp.supernews.com>,
=?UTF-8?B?UGFsaW5kcuKYu21l?= <me9@privacy.net> writes:
>
> Any thoughts? The strip is only handling 2-3Amps, so it isn't going to
> be too critical, getting the lowest resistance join possible.. But it
> probably gets to a few hundred degrees, so soldering it is probably not
> a good idea..

I've repaired toaster elements by crimping them together
with a bootlace ferule. You need to be sure the extra
weight of the join isn't going to cause it to move and
touch something it shouldn't.

--
Andrew Gabriel

Palindr☻me

2006-05-21, 4:21 pm

Andrew Gabriel wrote:
> In article <1271338htiao2e7@corp.supernews.com>,
> =?UTF-8?B?UGFsaW5kcuKYu21l?= <me9@privacy.net> writes:
>
>
>
> I've repaired toaster elements by crimping them together
> with a bootlace ferule. You need to be sure the extra
> weight of the join isn't going to cause it to move and
> touch something it shouldn't.
>

Thanks Andrew and Tim. The strip is sandwiched between the fire bricks
and so there isn't much room to play with. I did think of using a
stainless steel pop rivet, but there wouldn't be room unless I did a bit
of brick sculpture. What thermal cycling would do to such a join, I am
not sure - welding or brazing seems a better approach than something
which just clamped the components together.

I have a friend who is a jeweller and has a tiny oxy-hydrogen set* - I
think I will ask how he joins tiny ss bits together..

*Really neat - it just runs off water (and a bit of electricity)..

--
Sue

TimPerry

2006-05-21, 10:21 pm

"Palindr?me" <me9@privacy.net> wrote in message
news:1271dfn7d5b7h3e@corp.supernews.com...
> Andrew Gabriel wrote:
>
> Thanks Andrew and Tim. The strip is sandwiched between the fire bricks
> and so there isn't much room to play with. I did think of using a
> stainless steel pop rivet, but there wouldn't be room unless I did a bit
> of brick sculpture. What thermal cycling would do to such a join, I am
> not sure - welding or brazing seems a better approach than something
> which just clamped the components together.
>
> I have a friend who is a jeweller and has a tiny oxy-hydrogen set* - I
> think I will ask how he joins tiny ss bits together..
>
> *Really neat - it just runs off water (and a bit of electricity)..
>
> --
> Sue
>

stainless is really tough. it wont take solder. from working with theater
and disco lights i find that crimps dont seem to hold up in the long run.
this link may prove useful to you
http://www.jwharris.com/welref/procs/stainless/

i wonder if this is oxygen free stainless? (just kidding)

John Gilmer

2006-05-22, 12:21 am

> Thanks Andrew and Tim. The strip is sandwiched between the fire bricks
> and so there isn't much room to play with. I did think of using a
> stainless steel pop rivet, but there wouldn't be room unless I did a bit
> of brick sculpture. What thermal cycling would do to such a join, I am
> not sure - welding or brazing seems a better approach than something
> which just clamped the components together.

If you have a spot welder it will do a VERY good job on welding SS.

The problem with heater wire repair is that the repaired section has a
slightly higher resistance than the original stuff. The repair may "run
hot" and burn out early.

A way around this is to "double up" on the repaired section so that the
current through the repair has more than one path.

Mark Walter

2006-05-22, 10:21 pm

TimPerry wrote:

We do a lot of stainless welding and some brazing at my company. TIG and
Electron Beam (EB) welding mostly. We also do some brazing, I think you'll
find brazing pretty difficult w SS. The chromium (which makes it stainless)
is a tough oxide: we use vacuum brazing at very high temps (about 1500).
See if you got a buddy who can TIG weld it: probably for a one-up it will be
the best way

Mark Walter
>
> stainless is really tough. it wont take solder. from working with theater
> and disco lights i find that crimps dont seem to hold up in the long run.
> this link may prove useful to you
> http://www.jwharris.com/welref/procs/stainless/
>
> i wonder if this is oxygen free stainless? (just kidding)

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