Hello everyone, I am trying without much luck, to solder together two
domes to make hollow spheres, and lentil shapes to use as beads. I
have encountered a few problems. I have solderd a few together but
they look awful. The first is that I am heating the silver (sterling)
too much which is resulting in an orange peel effect to the domed
surfaces. I drilled holes in each dapped dome, and used a medium (#0)
torch tip with an acetelyne/air “B” tank. Would I be better off using
the larger tip (#1) and a gentler flame? The next problem I had is how
to keep the two halves together while soldering so that they are
properly aligned to each other. I fluxed the edges and let them air
dry. That helped prevent the flux from sputtering when I applied heat,
but gravity is still causing the halves to separate when the flux
becomes liquid. I tried sinking pins into my soldering block to keep
the domes from moving, but that didn’t work very well. I also tried
setting the dome into a hollow impression in the charcoal block. My
next attempt will be with binding wire (which I fear might cause
everything to collapse). Just thought I’d ask if there is some simple
solution I haven’t thought of yet.
Gail, Here is what I do…Make a hole in both sides…put a pin
threw both holes…hold pin with hemostats flux & solder …works
really good…Fires raging next door here in Florida, pray they don’t
get me for the 3rd time in as many years.
Gail , If you make one dome slightly wider than the other, the
smaller can be set inside of the bigger leaving a ledge which can be
fluxed . I think that it is easier for beginners to heat the flux to
the clear stage, turn off the torch and then place the solder bits.
Us the larger and more gentle flame and do not put the flame directly
on the solder bits. If you decide to wire the domes together, be sure
to put flex bends in by using the chain nose pliers to make bends. Too
heavy of wire may exert enough pressure to collapse the bead and
too
thin may cut into the bead if it is too tight (flex bends!) The
smaller the bits of solder, the quicker they will melt. Remember that
with silver, the whole piece needs to be brought up to temperature.
You will need to ensure a very good fit. If you are just starting,
I would recommend that you use fairly heavy guage like 20 or 22 so
that you will have a wider surface area at the joint. take both
haves and file/sand flat. Then put a peice of 320 or 400 grit emery
paper on a pane of glass (to have a perfectly flat sanding surface).
Sand both halves flat and fit perfect. You will need a hole
somewhere on the item to release gas during soldering. Your might
want to use hard paste solder on both surfaces. If you have
patterened domes, you may want to coat with whiteout or some solder
preventing coating. Use binding wire unless you have some
non-conductive tweezers that will fit your dome. Raise the heat on
the entire peice watching the seam and getting it to soldering temp.
Be sure you see the solder flow then remove heat quickly. You will be
able to go back and resolder if you miss a spot while learning.
Quench in water and pickle well. Good luck,
Hi Gail; Why not let gravity work for you for a change?
since you’ve got holes drilled in the domes, find a copper wire
that fits snuggly in the hole, heat it with a torch until it’s
oxidizes, so it won’t stick to anything.
stick the end of the wire a half inch or so into a charcoal block
so it sticks straight up.
instead of flux and solder pallions, order some sterling paste
solder from Rio Grande. It’s great for projects like these, it’s
really powdered silver braze mixed with flux into a nice, creamy
paste.
coat the inner lip of each dome, just inside and also on the
edges and put one dome, domed side down onto the wire, then thread
the other, dome side up, onto the wire.
get this setup ready in such a way that you can rotate it to get
the torch to it all the way around the circumference and then solder.
I think you’ll find that you get a good solder joint with much less
heat than you expect. By the way, try soldering with the lights
dimmed. That way you’ll see if it’s getting red, which is much
hotter than you need.
Dome and drill your two halves. Sand each half on a piece of
sandpaper on top of a piece of glass, until you have a flat surface on
the circumference all the way around. Cut two strips of sheet solder
(hard), which will be laid across the circumference of one half of the
sphere, about 1/3 and 2/3 across. Think of a circle with 2 vertical
lines, and this is how you will lay your strips. They should just
barely project past the outside diameter. Line up your top half on top
of the solder strips, so the solder strips are trapped between the two
halves. Now wire the sphere together with light binding wire (I use 26
ga. uncoated floral wire), in a criss-cross configuration. Suspend the
sphere from a third arm by the binding wire tail. Use a tip with a
large enough flame to bathe the sphere in heat. Coat the sphere with
flux. Continuously move the flame around and watch for the “flash” as
the solder melts. Remove from the arm and inspect the seam closely
to
make sure it’s soldered all the way around. If there are places which
haven’t flowed, reflux and heat again. After pickling, carefully sand
the seam until it’s invisible. That’s it. From the time you lay on
the solder strips to finish is about 3 min.
Hi Gail, I’ve soldered quite a few domes and found that a larger
softer flame is best.
As for securing the halves, creating a jig using straight pins and
long sewing needles with large eyes works well for me. The straight
pins serve as a base for the bottom hemisphere. I use three pins
imbedded in the soldering pad with the heads angled slightly toward
the center, this allows the heat to travel under the bottom without
acting as a heat sink (even heating is important with sterling) .
I use three large sewing needles, also imbedded in the pad, to hold
the top hemisphere in place. These are positioned so that they are
perpendicular to and even with the seam at the point of contact, thus
preventing movement of the top portion of the dome. Binding wire is
passed through the eyes and twisted snug but not tight. If there is a
place where it will not show or can be incorporated into the design, I
drill a hole in one of the domes prior to soldering to allow for air
expansion.
After pickling, I use a hypodermic needle to withdraw the pickle
through the hole prior to rinsing. Following the rinse, holding the
piece in my pickle tongs, I gently heat it over a wet paper towel with
the hole pointing down until the steam forces the remaining fluid from
the dome. I then inject a saturated solution of baking soda & water
to neutralize any remaining pickle. Rinse well inside and out !
If the design is such that a hole is obtrusive, you have a whole new
problem i.e… expanding hot air blowing out your solder joint. If this
is the case, let us know, it can be dealt with in other ways.
Hi gail, been there, done that G. I found the best way was with
binding wire. The idea is to form a cage for the sphere to sit in and
then tighten the cage around it. If you heat both halves evenly,
there should be no problem.
You will need a hole somewhere on the item to release gas during
soldering.
I was always taught this but recently someone told me that you don’t
need a hole to release gas the FIRST time you heat the piece; but if
you heat the piece again, you do. Is this true?
I take a pair of self closing tweezers and bend them until they
gently hold the two halves of the dome. When I use regular tweezers,
I get excited and use too much pressure and the bead collapses.
I presolder each side first and then sand the edges flat. I put
the two sides together and put them into the tweezers… I dunk the
bead into flux and then heat up the piece… the solder flows quite
nicely. I sometime roll the bead that is still in the tweezers across
my soldering board and the solder runs toward the heat, thus closing
the seam. I don’t drill holes in the beads until after the first
soldering. I have used this technique for silver beads up to 30 g…
Remember to set the size of the tweezers to the size of the bead. The
lack of great pressure on the bead is important.
Saw Andy Cooperman do this at a workshop and it is great!!!
gail - this works: center & drill the hole on each dome. butter the
inside edge of one dome with a thin smidgen of silver paste solder.
string the unbuttered half, open side up, onto a piece of binding
wire with a small loop at the bottom end (to keep them from falling
off). fit the buttered half open side down. line up both edges, make
a loose loop at the top & if you can’t get your partner to wrap the
wire around a finger (perhaps the one always pointed at you?), hang
it from something fireproof. use a side to side windscreen wiper type
torch motion along the ‘equator’ while turning the wire. several sets
of domes can be strung on the wire & soldered one after the other
since the heat from the previous one will be conducted to the next.
at this point your partner will be sorry for agreeing to hold the
wire; don’t worry, partners come & go but a good solder job is
priceless. good luck -
Beth, You do not need a hole in it for the first soldering. But if
you do not get a complete seal along the seam the first time you will
have a problem when you heat it again as it will probably “pop” and
send hot metal flying around the shop. I have done spheres some where
I did manage to get a complete seal on the first try but you are
taking somewhat of a risk if you re-heat without adding a hole.
However if you did get a complete seal on the first try you actually
have a partial vacuum in the ball as the heated air expands ant is
then sealed inside the ball and upon cooling it contracts leaving a
negative pressure inside the ball.
James Binnion Metal Arts
@James_Binnion
Member of the Better Business Bureau
Conventional wisdom says you need a gas escape hole to solder a
closed form. I have also spoken with at least one artisan who will
solder a closed form without a hole. I am not that brave. I believe
the greatest risk is the build up of pressure within the form, which can result in the explosion of the form under certain circumstances.
Think, “hot, precious shrapnel.” And what parts of your person are
usually exposed to the soldering process? Face, neck and chest (vital
organs).
I think it’s kind of like eye protection. You may be able to get away
without it for a while, but eventually something will occur to make
you wish you hadn’t. Try it at your own risk, like anything else, but
I wouldn’t encourage or promote the practice!
Dave, Fear not the shrapnel of flyingsilver when soldering domes
together without a hole in one. The worst that happens, at least with
me, is that there will be a little hole in the seam where the air
escaping prevents the solder from adhering, Jerry in Kodiak
hey Dave and the “other vital organs” I did some soldering of
"hollow-formed" jewellery for period of time. they can “take off” at
about 5 kms. and hour! …whoosh! the whole trick is to heat up the
item, and to expand the internal gases! then just when the item is
really hot, plug up the hole and let the item cool down “naturally”.
not bad for a setter doing some other kinds of work,eh? I was doing
about 100 solderings a day on these hollow charms. but I think now, I
should have used some body-armour!!!..whoosh again! gerry, the
cyber-setter!..“whoosh” is Canadian… for “it flew off again!”
Beth, You do not need a hole in it for the first soldering. I’d like
to mention that if you get a complete seal on the first try, true,
you will have “negative pressure” inside–and if your metal is thin,
or has a dent or weak spot, it may collapse inward because of that
partial vacuum. High school science classes (at least used to)
routinety collapse cans this way as a demonstration. A dome is
stronger, but… If I needed a totally sealed sphere, I think I would
put a tiny hole in it, finish it, then solder a piece of wire into
the hole at the very end, with my easiest solder, and
file it to invisibility. Just my two cents worth… Noel