solder glue, solder paste, solder replacement?

by marc_is_curious on Wed Sep 19, 2012 8:21 am

i wonder if anyone did ever work with
or recommend a "solder glue" or "solder paste"
in order to fix electronic components onto a breadboard ?

a material that ...
- is hard-when-dryed, permanent
- allows for soldering without applying solder wires or heat

----------------------------------
WHAT I FOUND SO FAR

- Conductive Epoxy
(Bisphenol-A-Epichlorhydrin & silver powder,
"Epoxid liquid metal", ...)

- several (rubber(?) based) paints/pastes
( instructables on -carbon powder based- conductive glue,
"wire glue",
bareconductive's "bare paint",
sherrihaab's "Graphite Conductive Paint",
"primasil" conductive rubber, ....
)

-------------------------------------------------

i thought it might be a good idea to ask for your advice/experience
before spending a lot of money ...

may you please let me know
or send a link for related products?

i look foreward to hearing from you -
best regards!
marc_is_curious
 
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Re: solder glue, solder paste, solder replacement?

by john444 on Wed Sep 19, 2012 7:13 pm

Hi Marc,

The products you mention have limited application in most electronic projects
due to high bulk-resistance of these products compared to solder.
Applications where conductive epoxy and paint are serviceable are those that
can tolerate moderate to high resistance such as driving LCD displays and RF-shielding.
However, applications requiring more than uA of current become difficult to
successfully implement.

Soldering has been used for a long time in many application.
It is inexpensive per joint and uses fairly inexpensive tools.
In addition, the techniques needed to be successful are easy to learn.

The feature list for soldering is long and varied.
Is there a specific reason you are searching for soldering alternatives?
John
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Re: solder glue, solder paste, solder replacement?

by marc_is_curious on Thu Sep 20, 2012 12:59 am

Hi John,

thanks a lot for your immediate reply!

i posted my inquiry because i am a "soldering-novice"
looking for alternative ways to fix multiple elements
onto a circuit (that is printed on heat-sensitive material)*;

i came across SMD stencelling/glueing techniques when googling
"solder glue" & thought that this could be a helpful approach
for my (non-SMD) project:
"just glue (or even stencil-paste-glue) it" (... without heating) .
....
*i am working with 3 Picaxe 08M2 chips that connect to 30 LED's
& voltage regulators on a film-printed circuit-
assuming that my configuration would take around 100mA** max
at runtime (not all LED's are active simultaneously)
....
**so on behalf of the resistance/uA it might work using epoxy/paint-
&
i tried a silicon based ("no heat required") paste
which did not stick to the film-material
though the connection provided enough conductivity
to connect my components
marc_is_curious
 
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Re: solder glue, solder paste, solder replacement?

by john444 on Thu Sep 20, 2012 8:55 pm

Marc,

I am not familiar with any silicone based conductive paints. My experience was with solvent-based & metal filled paints.
The metals could be powdered platinum, gold, silver, copper, nickel, stainless, lead, zinc, or carbon.
Platinum and gold were extremely expensive. Only the copper or silver were very useful at low mA levels when applied
very thick with multiple coats. The silver & copper filled epoxies were not nearly as good as the silver/copper paints.
Brushing was more effective than spraying. Consistent results were very difficult to achieve. Connections were easily
broken with slight flexing. Over all none of these products were satisfactory for our project.
However, any of these would have made good RF shielding. But, non-woven carbon-fiber was much lower cost.

marc_is_curious wrote:i came across SMD stencelling/glueing techniques

Solder-paste is an interesting idea.
Have you tried it? How well does it work for you?

John
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Re: solder glue, solder paste, solder replacement?

by marc_is_curious on Fri Sep 21, 2012 6:02 am

i did not try smd soldering pastes yet -
"glueing" components (without heating the circuits afterwards)
i tested a silver/copper/sillicon paste;

the connections' conductivity is brilliant -
due to the silicon binder the joints are quite flexible though
(hence any too hard movement will make the glued connections
pop off the components' metall pins)
that's why i thought of epoxy or similar resin based
binders ...
such like e.g. acrylic binders (used by artists) ...
Attachments
test-Sil_glue.jpg
.. some tests ...
test-Sil_glue.jpg (181.77 KiB) Viewed 2645 times
marc_is_curious
 
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Re: solder glue, solder paste, solder replacement?

by john444 on Fri Sep 21, 2012 7:41 pm

Marc,

Looks as if I have not kept up with the times. My mistake.
It appears that Lady Ada likes this stuff also.
That is a big endorsement. Check out ID : 514 & 515.

Best of luck with your project.
John
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Re: solder glue, solder paste, solder replacement?

by spitfireinno on Tue Feb 04, 2014 12:27 pm

If the high-resistance conductive glues (Bare Conductive and so on) aren't suitable, have a look at the various products from Atom Adhesives. They have a number of formulations with tradeoffs regarding resistivity, mechanical flexibility, dry time and so on. I've had great results with AA-DUCT 904, a silver-filled epoxy. It's pretty neat stuff. The main thing to know is their adhesives all have a shelf life of a few months -- be sure to refrigerate it, and don't order lots more than you need, since it will expire.
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