I need solder that's appropriate for soldering aluminum to copper or
aluminum to aluminum or aluminum to tin. I just do small hardware
projects on my own for fun, so it needs to work with a It should be
appropriate for use with a typical soldering iron. This is not for
large projects that would require a blow torch or heating torch or
whatever.
Anyway, just for context, this is for a quick little project where I
added an off switch to a clock. My girlfriend is always complaining
about how she never has enough time and wishes she could stop time, so
I decided to add an off switch to an analog clock. *smile*
Unfortunately, the solder I use doesn't stick to the positive and
negative contacts in the battery compartment. I assume this is because
they are made of aluminum.
I was able to find this stuff by doing web searches, but I don't
actually know which thing to get. I have only ever used the type of
solder that comes on a spool. I don't know what solder flux is. I
found some aluminum solder that looked like it came out of a squeeze
bottle. I don't know how I would use that since it's obviously already
liquid. Would it just be a sort of glue then which hardens after a
while? |
Request for Question Clarification by
aht-ga
on
26 Feb 2004 13:15 PST
mxnmatch-ga:
How certain are you that the battery contacts are aluminum? The
majority of consumer-grade battery contacts are made from
nickel-plated steel, similar to these:
http://www.keyelco.com/kec/standpro/prodcopy/prod35.htm
(click on the links at the bottom to see diagrams and material types)
Chances are that the reason your solder joints aren't holding, is
because the surface of the battery contact is not clean. As well, it
is always a good idea to give the solder something to hold onto, like
the edges of a hole or at least the edge of the contact. Did you clean
the contacts before soldering, using an alcohol-based cleaner?
The solder you were using is most likely a Tin-Lead type:
http://www.efunda.com/materials/solders/types.cfm
This material works well with nickel-plated steel, as long as you
prepare the surface properly first.
Please advise whether you are sure that the contacts are actually
aluminum, and whether you cleaned the surfaces first.
Thanks!
aht-ga
Google Answers Researcher
|
Clarification of Question by
mxnmatch-ga
on
26 Feb 2004 15:15 PST
You're right, I just assumed they were aluminum because when I looked
up what my solder could attach to, aluminum was mentioned as being
something that it would not attach to.
No, I haven't cleaned anything with an alcohol based cleaner. I know I
have some, but I can't find it. Would something like this be ok?
http://www.e-firstaidsupplies.com/store/merchant.mvc?Screen=PROD&Product_Code=922-00050&Store_Code=FPI
Will the alcohol make the solder stick by itself or will I actually
need to drill some small holes in the contacts? (That would be tricky
to do while they were still in the clock.)
|
Request for Question Clarification by
aht-ga
on
26 Feb 2004 15:56 PST
The main purpose of the alcohol-based cleaner is to be able to remove
any oils and dirt from the surface, without leaving behind any
residue. Soap and water would not work, because the surface would
retain some soap and any mineral deposits from the water. So, if you
have alcohol wipes around the house, that will work fine.
As for helping the solder to stick, here is what I personally would do:
If the contact is a leaf-spring type, I would strip off enough
insulation from the wire to be able to bend it under and around the
leaf, so that I could twist the wire back around itself. Then I would
solder the twist together, and fill in the spaces between the wire and
the leaf with solder.
If the contact is a coilspring type, I would again wrap the wire
around the coil, and go crazy with the solder to permanently bond the
two together.
If the contact is a button-type, I would form a U-shape with the wire,
curve it around the 'button', then solder in between the wire and the
raised 'button' to give maximum coverage. In fact, if there were
anyway to remove the button contact or get to an edge of it, I'd
prefer to work there and solder the wire to the edge. You will also
need to heat up a button-type contact longer to ensure that you are
not making a cold solder joint.
Let me know if this advice helps, and I will post it as the Answer.
aht-ga
Google Answers Researcher
|
Clarification of Question by
mxnmatch-ga
on
14 Mar 2004 15:43 PST
After using sand paper and a Wet-One wipe (I assume that Wet-Ones are
like alcohol wipes), the solder still doesn't stick to the battery
contacts at all. When I heat up a contact with the soldering iron and
then put the solder to it, it just slides right down and onto the tip
of the iron.
So, I took your advice and just wrapped the wires around the contacts
and soldered the twists until they were reasonably tight on there.
That works, and I'm fine leaving that as is, but I still think it's a
bit strange that the solder doesn't adhere to the contacts at all.
They certainly don't look abnormal, so you're probably right that
they're tin. I suppose I could try scraping hard on them with a small
screwdriver or something since the sandpaper didn't actually seem like
it did much.
|
Request for Question Clarification by
aht-ga
on
14 Mar 2004 20:22 PST
Actually, Wet Ones are usually made with some form of soap or
detergent, as opposed to an alcohol base, so there's a good chance
that the Wet One(s) would have left behind some soapy residue. The
reason why the solder preferred the soldering iron versus the
contacts, though, has more to do with heat distribution than how well
you cleaned the surface. If you were to heat up the contacts to a
higher temperature first, then apply the solder to the contacts rather
than to the point where the soldering iron is touching the contact,
then the solder would stay on the contact. The difficulty in doing
this is that you run the risk of heating the contact up too much, and
either melting the clock case, or causing a connection on the other
side of the contact to come loose. So, for a quick fix such as what
you are looking for, the "twist it and solder it tight" approach works
quite well.
This, of course, leads to the difficult request for clarification,
namely, how can I help you best in providing an Answer? Our discussion
has strayed somewhat from your initial query about solder types. Would
you be satisfied if I posted as an Answer, a summary of what we have
discussed here regarding different techniques to solve the problem?
Regards,
aht-ga
Google Answers Researcher
|
Clarification of Question by
mxnmatch-ga
on
14 Mar 2004 22:31 PST
Sure, go ahead and post it as an answer.
|
mxnmatch-ga:
I am posting a summary of our discussion above, here as the Answer.
To your initial question regarding solder types for different types of
material, I referenced you instead to:
http://www.efunda.com/materials/solders/types.cfm
for information about the various types of solder generally used, and also to:
http://www.keyelco.com/kec/standpro/prodcopy/prod35.htm
(click on the links at the bottom to see diagrams and material types)
for information about common contact types made from nickel-plated
steel. These are the most common because steel's springiness is ideal
for maintaining contact pressure through various insertion/removal
cycles for the batteries over the life of the clock. The
nickel-plating, helps to prevent corrosion.
We then discussed various possible solutions for achieving a strong
connection between your wires and these contacts. Generally, when
soldering two dissimilar metals together, the key to a strong bond is
to allow the molten solder to flow around a physical structure, so
that it creates a strong connection once it solidifies. Usually, this
means either a hole, or a suitably rough surface featuring many
'valleys' for the solder to contact the maximum surface area.
Unfortunately, nickel-plated steel is relatively smooth, meaning that
your best option is to use an existing hole, create your own hole, or
create some other form of physical structure for the solder to flow
into and bond. One way to do this is to wrap your wire around the
contact and twist the wire back onto itself. This allows you to flow
the solder into the twist, and into the space between the wire loop
and the contact.
We also discussed how to best prepare the surface for soldering, with
an alcohol cleaner being the recommended solution. Unfortunately, only
a true alcohol-based cleaner will remove any foreign materials from
the surface of the contact. Soap or detergent based cleansers will
tend to leave behind residue that will interfere with your soldering.
Incidentally, here is a website with tips on soldering on circuit
boards, in case you are interested:
EPE "Basic Soldering Guide"
http://www.epemag.wimborne.co.uk/solderfaq.htm
I'm glad that I was able to help!
Regards,
aht-ga
Google Answers Researcher |
