Paste solder not holding

Hi, I’m hoping someone can give me advise on using paste solder. I
have just starting using it as it seems like a dream come true for
certain projects. I successfully used it for soldering a ring to the
bezel back… wonderful, just stuck the ring into the paste on the
bezel back and worked great. Well since then I have used it to solder
cut out flowers (24gauge Argentium) onto an 18 gauge argentium
pendant, seemed to work well until I used the buff wheel to polish
and off they came. I thought, well I didn’t heat the base well
enough… heated again and hopefully it will stay together.





Yesterday I was using the same technique soldering cut outs to an 18
gauge A silver cuff… made sure I heated the cuff silver first and
then to the top to the soldered pieces… I heated it to the point
of almost fusing the flowers, (they definitely had that shimmering
glow just before melting) so I was sure I had them all on. I polished
a bit and went to the bracelet mandrel…2 bangs and …that’s when
everything started to comeapart… flowers and leaves flying
everywhere… I stopped hammering and now am trying to decide…
should I keep forming the cuff and see what else comes off so I can
fix it later?? or should I re heat whats still on and try again?
Also, what am I doing wrong in the first place??? Is paste solder
not as strong as sheet solder? Would appreciate any thoughts… Thanks
and Regards, gail

Since you mentioned Argentium, is that the only silver you’re using?
Is your paste sterling or argentium paste? Is the paste Easy, Medium
or Hard solder paste? Argentium requires a lighter hand than regular
Sterling and shouldn’t be heated too high. That’s why you shouldn’t
use hard solder with it since the Argentium will melt before the
hard solder does. There is Argentium specific solder in sheet, wire
and paste form that should be used if you’re not going to fuse the
pieces. Remember, thermal conductivity is much poorer on Argentium
so you can almost eliminate the need to heat the sink as you would
with Sterling. I haven’t soldered Argentium yet since it fuses so
beautifully but these are some things I’ve learned along the way.

As far as I know paste solder is just as strong as sheet solder but
it does have it’s limitations. Because the flux is incorporated into
the solder, you will have less solder in the join than using sheet. I
only use paste solder for closing jump rings or applying joining
delicate pieces where it’s difficult to get a pallion in place.

Michele
MikiCat Designs

The paste solder, is it the argentium solder paste? I have used the
argentium paste and loved it. I do filigree so the occasional ball
would fly Thing I found with argentium as is with sterling, it gets
harder and harder On one piece I could not for the life of me get 2
balls to stay. Had to heat to the point of almost melting the whole
piece. The other, is make sure it is very clean. Get the majority of
the work done and just getting the hint of glow and stop. Wait for
the metal to cool a bit before you quench… and pickle,other wise it
will get harder. Then do your final pieces, then the whole piece get
the slight shimmer and again let it slightly cool before quenching.
Then pickle. Since doing that I have had no problems. Sometimes
roughing up the area will help with the bond as well.

Hope that helps
Trish

If you were applying the paste solder from a syringe, the problem
may have been caused by the mixture of the solder & flux in the
syringe.

I’ve had times when the flux & solder in the syringe weren’t mixed
correctly & what was extruded from the needle wasn’t a mixture of
solder & flux but just flux. If you watch the color of the material
that’s extruded you’ll notice that the correct mixture has a dark
gray color (assuming it’s sterling). When just the flux is extruded,
it’s color is lots lighter. The last time I saw it happen, the flux
color was somewhat on the tan side. It also looked a little toward
the translucent side. Obviously, with no solder in the mixture the
joint won’t hold.

This separation of the flux & solder usually shows up in a syringe
of paste solder that has been used previously & then not had the
needle plugged or the cap put on the end of the syringe.

Dave

When trying to solder small silver granules to 18 gauge sheet (I
think that’s what you said), a typical problem is that the sheet
isn’t getting hot enough. The granules get hot and they seem to be
soldered onto the sheet, but they’re not. Try putting the sheet on a
tripod and heat it from underneath

A possible cause is that most of the flux liquid has dried out over
time from the syringe, leaving the solder to not penetrate the join
fully.

Remedy -Returning the remaining unused syringe to the supplier to
have a little flux inserted and mixed in.

cjh -from sunny New Zealand

just bought it and dry = return

had it months and months…or longer, get out your cupronil or any
liquid- battern’s flux for example, squirt out the paste, mix it to
the right consistency and draw it up into the syringe and cap tight-
or leave in a bit of water or glycerine to cover the needle’s tip if
using it daily for production, etc…

rer

had it months and months..or longer, get out your cupronil or any
liquid- battern's flux for example, squirt out the paste, mix it
to the right consistency and draw it up into the syringe and cap
tight- or leave in a bit of water or glycerine to cover the
needle's tip if using it daily for production, etc.... 

Another good liquid for mixing with paste solder that’s become stiff
& dried out is mineral spirits. Add 3 or 4 drops, mix & test before
adding any more. It doesn’t take much.

If you keep a syringe or 2 on your bench & don’t remove the needles,
a good way to to plug the needles is with a piece of music wire. Take
each size needle you use with you to the hardware store & select a
piece of music wire that just fits into the needle.

When you get home cut off about a 2 inch (80 mm) piece of the wire &
put a 90 degree bend in it about 1/4 inch (6mm) from one end. This
will act as a handle & make it a little easier to pick up off a flat
surface.When picking it up from a flat surface, rub your finger
across the wire. This will cause it to roll & you’ll be able to
grasp the wire.

I’ve used this method for years.

Dave

I use the paste solder from myuniquesolutions.com because it never
dries out. Some of my syringes have been open for years and are
working fine. No affiliation, just a happy solderer.

vera