What metal is it? Soldering is quite a complex thing, as soldering
dissimilar metals often needs special flux and sometimes different solder as
well.

Brian

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The Sofa of Brian Gaff...

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"David" wrote in message
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On Sun, 01 Apr 2018 17:23:48 +0000, David wrote:

We have a load of lampshades which are made from loops of metal with (I
think) plastic inside - like little portholes.

http://s817.photobucket.com/user/Lit...trange%20bits/
Lampshade%20Soldering/Lampshade.jpg.html

As far as I can tell all the circles of different sizes are soldered
together, then the ring to fit onto the light fitting is soldered on
with three little wire arms.

One of these wire arms has become detached from the ring.

I am attempting to solder it back, but not doing too well.

My biggest soldering iron is 45W but this doesn't seem to be able to get
enough heat in to solder to the ring. It will melt the solder on the
wire,
but that won't stick to the much large expanse of metal. I've tried
heating the ring from the back in the hope that the solder will flow,
but nothing.

Next up in the power stakes is my pen torch (gas powered).

https://www.amazon.co.uk/Pencil-Buta.../dp/B004K7ME5S

This seems to be a bit too powerful. Certainly hot. Solder just blows
away in the flame as far as I can tell.

So how do the manufacturers make these things?

Is there something in between (perhaps 60W or more) which will give
enough local heat or am I scuppered because the ring part conducts the
heat away too quickly?

Is there an alternative such as an adhesive which might work? Tiny bit
of body filler perhaps?

O.K. - should have looked more closely on line instead of accepting that
30W is normal and 45W is large.

Plenty of 100W soldering irons for not much money, but 120W gets a tad
expensive.

So I think I should rephrase the question into "how much power am I likely
to need to spot heat this kind of structure".

I assume that I have to get the heat in locally very quickly so it doesn't
just dissipate into the rest of the metal.

Cheers



Dave R


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