Re: [NTLK] emate battery

From: Marco Mailand (Newton2k1_at_mac.com)
Date: Tue Aug 21 2001 - 08:29:26 EDT


There's so much talk about such basics like soldering and obviously a
certain demand on answering all these questions that it seems to be valuable
to create a FAQ section therefore and avoid repeated posts. Possibly does
something like this already exist, as it does e.g. for brazing. However, I
would like to chime in again and add my comments to Robert's excellent
remarks:
> ...don't worry about melting your soldering lip, since it isn't made from
tin it
> won't melt as fast as your soldering tin.
The soldering lip is made from thin stainless steel like the can or tank of
the accu. The lip is connected by a spot welding joint to the bottom of the
can. Since the melting point of stainless steel (ca. 1200 deg C) is about 4
times higher than the one of the tin/lead solder (280 deg C) it is
absolutely impossible to melt the soldering lip nor to damage the spot
welding joint. However, the soldering lip is made for spot welding and
probably not for soldering and the problem is that the stainless steel
doesn't solder very well if untreated. The particular problem is the oxide
layer on the surface. If this layer is removed by scratching with a nife or
grinding paper stainless steel can be soldered with standard tin-lead solder
and collophonium and eventually w/o soldering grease. However, during
soldering the protecting oxide layer is quickly re-built and prevents the
solder to flow over the whole lip. Therefore one has to use a well heated
soldering iron to heat up the lip very quickly in order to have the solder
flowing quickly over the whole clean area. This should be possible within
about 10s after the first touch of the soldering iron. If the solder doesn't
flow, you should clean the lip again and start over. Flowing solder means
that it distributes by itself over the cleaned solder lip area and doesn't
form bubbles.

> Please take my advice and practice a bit on partially stripped wires (at
> first twist them around each other) before so that you can get the feel of
> it, once you see the moment of the heat taking and the tin flowing and
> solidifying the connection you'll basically are on your way.
It is also important to guarantee at least 2...5sec minimum soldering time.
If one touches the soldering joint with the iron only for less than 2s the
time is not enough to heat-up the wires sufficiently to get the tin
diffusing into the wire surface.

> good luck to our Newton soldering class ;-)
...and welcome to the hot tin club ;-)

--
With best regards / Viele Gruesse

Marco Mailand http://slsbd.psi.ch/timing

-- This is the Newtontalk mailinglist - http://www.newtontalk.net To unsubscribe or manage: visit the above link or mailto:newtontalk-request_at_newtontalk.net?Subject=unsubscribe



This archive was generated by hypermail 2.1.2 : Sun Sep 09 2001 - 19:47:28 EDT