[Noisebridge-discuss] soldering copper sheet metal

Henner Zeller h.zeller at acm.org
Fri Nov 6 21:07:36 UTC 2015


On 6 November 2015 at 13:01, Henner Zeller <h.zeller at acm.org> wrote:
> On 6 November 2015 at 11:57, jim <jim at well.com> wrote:
>>
>>     I've uploaded photos of my failed attempts to
>> solder copper sheet metal :
>>
>> http://www.systemateka.com/Copper/
>>
>>
>>     Each of the three jpg files shows the same things
>> from different camera POVs.
>>
>>     The longest copper strip separates the foreground
>> attempts, tried various types of glues from the
>> background attempts, tries with various types of
>> solder and flux.
>>
>>     The soldering iron advertised 950 degrees F; the
>> (blue) propane advertised 2000 degrees F; the (yellow)
>> MAP advertised about 3000 degrees F.
>>     Each got the copper (30 gauge and 24 gauge) hot
>> enough to melt the solder. The propane was hot enough
>> to get the copper bright rid. The MAP was hot enough
>> to vaporize the copper and let a little drop of
>> molton copper fall.
>
> Too hot! For soldering, you actually don't want to go much higher than
> what needs to be done to melt the solder. Which means any torch based
> attempt is probably too hard to control.
>
> If things are too hot, then you burn the flux, and if even hotter, you
> evaporate part of the solder which will change the composition of the
> alloy, making it work worse.
>
> For best results (I guess you already tried that), the copper needs to
> be at the place of soldering; this is what flux is good for (in your

This should read "needs to be _clean_ at the place of soldering"

> case, with no electronic parts, even acid flux is ok; you get it for
> copper-pipe buidling supplies).
> The rosin is good flux while soldering, but for these big parts
> pre-cleaning it with some acid-based flux is good.
> Of course, mechanical means (steel wool?) might as well to get you started.
>
> What I often do when I have to solder something that sucks off a lot
> of heat (such as: huge pieces of copper that are very good in
> conducting heat away from where you want it :) ), put it on an (old)
> electric stove (with a solid platter, not this spiral thing rubbish)
> to get up to temperature or close to temperature. Then whatever you do
> with the soldering iron gets you much further.
>
> It is not the final temperature of the iron that counts, but if it can
> keep going in putting enough energy in when the material (here:
> copper) sucks away the heat.
> An iron with at least 100W is probably needed for your task (can't
> read it on the image).
> (950F is actually too hot, you want to be not much more than 600-700F
> on the material). The additional heating with the stove platter helps
> you getting better overall even heating and less premature cooling
> with a smallish iron.
>
> Also it avoids avoiding (too hot) solutions such as propane/MAP.
>
>>
>>     My interpretation of the dark brown residue on
>> the pieces in back is that is cooked rosin.
>
> yep, that is probably a fair assessment. Things were too hot.
>
>>     I've tried various glues: goop, water weld,
>> super glue, krazy glue, liquid nails.... None of
>> them hold enough to resist being pulled apart (with
>> mild force).
>>
>>     I believe it'll be best for us to find someone
>> who can do the work: we have various models to show.
>>
>>     Anybody interested in taking this project on? My
>> guess is four to eight hours total, flexible time.
>>
>> Hopefully, with thanks,
>> jim
>>
>>
>>
>>
>> On 11/01/2015 03:34 AM, jim wrote:
>>
>>
>>     oh: yes, I want to solder the pieces together.
>> I've tried with clamping--no dice.
>>
>>
>> On 11/01/2015 03:28 AM, jim wrote:
>>
>>
>>     yes. I've cut small pieces of 30 gauge and also 24
>> gauge and have tried to tin them (tin 'em first, then
>> solder them together, yes?) with horrid results: a dark
>> brown crust develops that shows little round pin-head
>> sized circles and the solder just sits in a ball and
>> then rolls off.
>>     I've used two different types of flux and various
>> types of solder (tin-lead, silver...).
>>     I've gotten the copper bright red with a propane
>> torch. I've used a soldering iron.
>>     I've washed them with alcohol, paint thinner, and
>> muriatic acid; I've also washed them with a solution
>> of lye and sodium carbonate and borax. I've sanded
>> them with fine and with coarse paper, by hand and
>> with an orbital sander.
>>
>>     In the past I've soldered electronic circuits and
>> copper pipe successfully.
>>     A couple of experienced people say it sounds like
>> the surface of the copper sheets is contaminated, but
>> golly! After all that scrubbing and washing and flux
>> and heating?
>>
>>
>>
>> On 11/01/2015 03:08 AM, Cere Davis wrote:
>>
>> So ur just trying to solder copper to copper?
>>
>> On Oct 25, 2015 4:37 PM, "jim" <jim at well.com> wrote:
>>>
>>>
>>>     I've soldered electronics and plumbing and
>>> am stuck trying to solder copper sheet metal.
>>> I've used a soldering iron and a propane torch.
>>> I've used alcohol, acetone, and paint thinner
>>> to clean the copper as well as fine and coarse
>>> sandpaper to clean the surfaces. I'm using
>>> electronic flux (haven't yet tried plumbing
>>> flux).
>>>     The soldering is not working: solder does
>>> not flow or adhere to the copper, and there's
>>> a brown residue that appears after heating.
>>> Using a torch for forty or fifty seconds
>>> results in flame that does not immediately
>>> expire.
>>>
>>>     Anybody got tips?
>>>
>>>
>>>
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>>> Noisebridge-discuss at lists.noisebridge.net
>>> https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
>>
>>
>>
>>
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