chips vs chad
ard at p850ug1.demon.co.uk
Fri Apr 9 16:14:13 CDT 2010
> > > > Easy -- coat them with aquadag and then copper-plate them before tinning.
> > > . . . or fire up the punch, and make a batch of chips out of "tin foil"
> On Fri, 9 Apr 2010, Tony Duell wrote:
> > Most 'tin' foil these days is aluminium.
> Here it's generally made out of aluminum. But it seems to be pretty
As I am sure you're aware that was not one of my typos...
> > And due to the oxide coating
> > it's a right pain to solder to. It is posible to solder to aluminium with
> > normal solder and flux (I have done it) -- the trick is to put a drop of
> > oil on the aluminium, then scrape the surface under the oil and quickly
> > tin it with a hot iron and solder. Most of the time it will tin. Once
> > it's tinend it's easy to solder a wire (or whatever) to the aluminium.
> That tip will be quite useful for some OT automotive projects!
It is only soft soldering so it's not very strong (don't use it for
anything structural!), but it does work. Once you've got the solder to
flow onto the aluminium (that is, not sit as a 'blob' on top), then it is
not hard to sodler a wire to that point, for example.
I can't remember why I needed to solder a wire to an aluminium electrode,
but I did and it worked fine.
You can get speical aluminium solder/flux. The stuff I came across
contained cadmium (!), and apparently there is a detectable amount of
cadmium in the fumes given off when soldering with it. That bothers me a
lot more than leaded solder, say.
> > But I wouldn't fancy trying to do that with 'tin foil'
> Any "tinning" of punched card chips and chad is going to be difficult,
> even if you did make them out of "tin foil".
>From readoign some old books on electricity (say 1920's vintage), it
would appear that 'tin foil' was once something other than aluminium.
Said books talk about making a waxed paper and tin foil capacitor (oops,
'condenser') and then soldering the foils together. No comment about any
problems with such soldering.
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