Several students are trying to solve a problem: This is what is
being done and what is happening to the project.
Imagine a 1/4" disk of 16 Gauge, to which 14 Gauge wires are soldered
(end which is soldered is flattened so it fits on the disk) , there
are between 5 and 9 of these spokes) – the result looks like a
spider (little body, long legs).
The problem which occures is: After soldering and pickling, as the
wires are bent up, they are cracking off. I am assuming that this
happens because the body (disk) is heavier gauge and requires more
heat, than the wires, for the solder to flow. To avoid overheating
the wires we have tried heat sinks on the wires. Nothing changed . .
. the wires continue to crack off (by crack, I mean, the metal
appears to be brittle and will bend, but then a crack appears and
then the wire breaks off.) We, initially thought that it may have to
do with some bad copper, but are finding that the same is happening
when using sterling wire and a copper disk.
Any advice or suggestions to solve our dilemma would be greatly
appreciated. Thank you, in advance.
Sounds like a stress riser problem because of the change in section
caused by the flattening and a solder that is harder than the copper.
what is the solder material? If this is the case all the stress in
bending is taking place where it breaks obviously and the solder is a
little more brittle than the base metal. This is not an uncommon
failure mode. The pickle may be also causing micro cracks at the same
junction point to start the failure off.
Jesse
Where are the cracks located in relation to the solder joint? Is it
the solder joint itself that is cracking, or the wire spokes-at what
distance from the joint?
She is using silver solder (both medium and hard have been tried with
the same results!) The “legs” are NOT breaking off at the solder
point, but about 10 mm’s away from the base (base- is the disk
shape.) When being bent to form a onion dome shape --gentle bend,
not a 90 degree angle or such.
smoosh & flux the ends of the wires & the disk. then heat the disk
from the bottom only - leave off the heat sinks, they’re exacerbating
the problem by absorbing the heat on the wires instead of increasing
it on the disk & then transfering it to the wires, melting the solder
in the process - use the heat transfer law of thermodynamics to keep
that poor ‘spider’ off of disability. ive
Have you tried giving the whole piece a light annealing after
removing the flux etc. I don’t know why that might work but it has
worked for me on some strange looking projects. Perhaps it evens out
the structure in the metal. Thinking out loud perhaps your problem
is that some way or another you’re accomplishing heat hardening of
the metal. I don’t use the process myself, but that is when the
metal structure becomes regular, sort of like a brick wall. I think
McCreight’s basic book has a diagram about how that happens. Good
luck and let me know if it works for you.
The "legs" are NOT breaking off at the solder point, but about
10 mm's away from the base (base- is the disk shape.)
I’m a newbie (in essence), but it sounds like the metal wires simply
haven’t been annealed properly – either that, or they’ve been
overheated and become “burned out”. Copper is usually soft as
butter… all I can advise is annealing the wires well first and
then soldering them on.
Several students are trying to solve a problem: This is what
is being done and what is happening to the project. Imagine a 1/4"
disk of 16 Gauge, to which 14 Gauge wires are soldered (end which is
soldered is flattened so it fits on the disk) , there are between 5
and 9 of these spokes) -- the result looks like a spider (little
body, long legs).
maybe they could try cutting slots in the disc where the wires are
attached. the wire would then be soldered on three sides giving a
stronger joint and allowing the legs to be bent more easily through
the cross section of the wire and not across the solder joint.
What about bending the legs first to the shape you want, then
soldering using a third hand to hold them in place? This has worked
for me in somwhat similar circumstances. --Vicki Embrey
I ran into a difficult soldering problem a couple of years ago. I
finaly solved my problem by investment soldering. perhaps this will
help you. First super glue the parts together in the position you want
them to be when the soldering is done. Then mix up some casting
investment and set the piece in the investment so that it will hold
all of the parts in place with all of the spots to be soldered
exposed. once the investment is hardened it will hld all of the patrs
in place, though it will absorb some of the heat from the torch. once
all the soldering is done simply wash away the investment.
Michael / QuestFox
I ran into a difficult soldering problem a couple of years ago. I
finaly solved my problem by investment soldering. perhaps this
will help you. First super glue the parts together in the position
you want them to be when the soldering is done. Then mix up some
casting investment and set the piece in the investment so that it
will hold all of the parts in place with all of the spots to be
soldered exposed.
Hi,
We use this in dentistry much of the time. There are soldering
investments made, I use one made by Coe, that set quickly and when
mixed, have a thicker consistency for easier workability. BUT…
It is best to put the invested articles in a cold burnout oven and
run it up to 1000 deg F in 30 min. (33 deg per min) because the water
in the investment will boil and, if you are lucky, (and if you hold
your tongue right) only crack the investment and move the parts. If
you are unlucky it can explode violently in your face. You can also
use a hot plate with a flat piece of metal on the burner/coil and the
invested piece covered with a vented tin can. We often use the
investment as a heat sink or as a protection for something (like
dental porcelain) that can take the heat but not the direct flame.
The investment also slows the cooling rate and prevents distortion
and shocking of the metallic crystalline structure providing you
don’t quench immediately. If you are imbedding the parts totally in
the investment, you must leave room for the flame to heat all sides,
so after super gluing, take a wax spatula and flow stickey wax all
around the joint(s) so you will have the room. If anyone needs to
know more, you can e-mail me off list.
Regards,
Skip
Skip Meister @Skip_Meister
Orchid Jewelry Listserve Member
A day without sunshine is like night!
N.R.A. Endowment
“No man’s life, liberty or fortune is safe…while our legislature is in session.”
Benjamin Franklin
Hi, I have used super glue to hold pieces together in soldering only
once, Then a associate question the fumes given off when heated!Ethyl
cyanoacytate sounds too much like cyanide! Is there any relation?
Does any one have any info or experience they can share? Thomas
Any time you burn off any of the modern adhesives, including but not
limited to, epoxy, cyanoacrylate, pearl and crystal cement; it should
be done with ventilation. All of these give off toxic fumes, some very
deadly! So if you don’t have a bench equiped with a hood, go outside
at the very least.
hi all: have you ever got the vapor from super glue in contact with
your eyes??? no fun experiance … cyan is always a relation to
cyanide …hydrocyanic acid (bombing)for example…spill some of
that on you and your liver will show problems… so i would think
that if you look at the way the fbi uses superglue to bring out
latent prints(they burn it and the result sticks to the glass but not
the oils) it is a very penetrating vapor and i don’t believe that
breathing it is healthy at all… ringman john henry
..... cyan is always a relation to cyanide ...hydrocyanic acid
(bombing)for example....spill some of that on you and your liver
will show problems.... so i would think that if you look at the way
the fbi uses superglue to bring out latent prints(they burn it and
the result sticks to the glass but not the oils) it is a very
penetrating vapor and i don't believe that breathing it is healthy
at all......
A little basic chemistry seems in order here. the key componant of
cyanide is simply a carbon atom hooked to a nitrogen atom. Nothing
complex. The CN ion, which is what you get when you hook those two
atoms together, happens to have chemical properties which are somewhat
similar to oxygen itself, especially in the way it bonds to iron, and
in a couple other instances. And it’s useful simply because it’s
capable, like oxygen, of bonding to ions of useful metals, including
gold, which oxygen does not do so well. If the CN ion is in a readily
available form, it then can be toxic by competing with oxygen in the
body, in red blood cells, where it blocks those cells ability to then
carry oxygen (because it’s already carrying the CN ion), and
similarly, in cellular level respiration, as well as a couple other
key functions. But CN is not some highly complex, or automatically
toxic combination. Only when it’s a free and available ion, or in a
chemistry where it could easily become so. For example, ferrocyanide,
where the CN ion has already bonded to iron, is quite stable, and only
mildly toxic. Not very deadly. HCN, hydrocyanic acid, or prussic
acid, on the other hand, is what you get when you add other acids to
cyanide solutions. Because it’s a mobile gas, and readily dissociates
again to Hydrogen and free CN ions when it dissolves in water, it’s
highly dangerous, and can be very quickly fatal. Just because a
chemical has “cyano” etc, in it’s name does not automatically mean
anything at all about it’s toxicity. Cyanoacrylate, or super glue, is
not chemically very toxic to you, at least not on account of the CN
ion that is part of the chemical. But it’s a dangerous material
simply because of it’s adhesive qualities, the way it reacts with
water (part of the polymerization reaction that makes it set up), and
the fact that the fumes are quite irritating. John is right, of
course, that you should not breath more cyanoacrylate fumes than
needed, and the burning chemical isn’t so good either (like the fumes
of many burning organic compounds and plastics.) And don’t let the
glue or it’s fumes into your eyes. But in both cases, the “cyano”
componant of the chemistry of super glues is not an automatic culprit
from similarities of the name to the deadlier cyanides…
peter rowe - absolutely outstanding explanation on the cyanoacrylic
glue issue! not only did i enjoy reading it, but it was
bang-on-target. regarding the adhesive danger to skin & other
propinquitous anatomical parts, again let me tout that great releaser
of all things sticky: uncommon conglomerates, inc’s ‘debonder solvent’
(a company in which i own no stock or know anyone who works there), it
has gotten me out of some very - won’t say it - places, & removes all
gems without damage - it has removed super glue from my lip without
even feeling a tingle (& even spicy foods ‘burn’ them!) ive
While this product, or acetone, or other solvents for various glues
do help to unstick accidents, it’s far better, and somewhat important,
to avoid the accidents altogether. if you use these glues, use them
with sufficient care NOT to get them stuck to body parts. The reason I
note this is not just that it’s a bother or a pain to pull the stuck
parts apart, but also because these solvents are NOT completely safe
to use on skin. Yes, you have to use them now and then, but be aware
that most such organic solvents, especially the ones active enough to
be effective on super glues or epoxies, are carcinogenic. This isn’t
just scare tactics, folks. These things cause cumulative effects,
and one day you’ll find yourself with lymphoma or the like, not
knowing why. My father is currently fighting what will probably be a
loosing battle with that condition, and the unproven but suspected
culprit is his many years as an organic chemist. Back then, people
weren’t so careful with carbon tetrachloride or benzene or the like as
their dangers were not then completely recognized. Organic solvents
can be absorbed through the skin as well as emitting fumes you then
breath. Use them as little as possible, and then only with good
ventilation. If you’re clumsy enough to be frequently gluing your
fingers, then consider using latex gloves or similar. They’re cheaply
had. Harbor freight, for example, will sell you a box of a hundred
for about 6 bucks, and their use will mean you stick the glove, not
your finger. As to getting super glue on your lip… Well, I guess
I don’t wanna know how that happened… But don’t DO that… (grin)