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Gold soldered to Titanium?


#1

Hello group,

Because I designed myself into a corner and am unable to bond
otherwise (laser for example), I have a need to TRY and solder a
piece of 2mm gold wire to a piece of 6-4 Ti. The wire will fit nicely
into a radiused channel. I know oxidation is the killer here, but
I’ve heard some have had limited success by using particular fluxes
or techniques. Anyone care to share their experiences?

Thanks in advance.
Jeffrey McWhinney


#2

As far as I am aware it is not possible to solder titanium at all -
full stop. Apart from mechanical joining with rivets or screws etc.,
laser or PUK welding with argon is your only solution.

Regards, Gary Wooding


#3
Because I designed myself into a corner and am unable to bond
otherwise (laser for example), I have a need to TRY and solder a
piece of 2mm gold wire to a piece of 6-4 Ti. The wire will fit
nicely into a radiused channel. I know oxidation is the killer
here, but I've heard some have had limited success by using
particular fluxes or techniques. Anyone care to share their
experiences? 

I think you will be better served to redesign to allow for some kind
of mechanical joint. It is true reactive fluxes and magnesium based
solders make it possible to torch braze titanium to titanium but I
don’t know if it is possible to braze to gold with these materials.
I am afraid if the solder wets and flows at all it will form brittle
intermetallic compounds that will not provide any strength. But if
you want to try one place to contact is
http://www.titanium-brazing.com/

If you do let us know how it works out.

Jim

James Binnion
James Binnion Metal Arts


#4
As far as I am aware it is not possible to solder titanium at all
- full stop. Apart from mechanical joining with rivets or screws
etc., laser or PUK welding with argon is your only solution. 

Titanium is routinely brazed (soldered) in argon and vacuum
atmosphere furnaces. It is occasionally brazed with a torch but this
is very problematic process that requires special flux and brazing
alloys that are either aluminum or magnesium based and a very
skillful person doing the brazing.

James Binnion
James Binnion Metal Arts


#5

Hello Jim;

Might it be possible to drill a small cavity in the titanium, then
use a laser or pulse welder to fill it with white gold, then solder
to that? I’ve used my pulse welder to get gold to stick to titanium,
although I wouldn’t trust it’s strength for a joint. But filling a
small depression, there’s no appreciable stress on it for something
like an earring post.

David L. Huffman


#6

To Jeffrey, James and Gary:

You CAN solder (braze) titanium with silver solder, which is how
airplane wings are assembled. Silver bonds well to titanium without
forming intermetallic compounds, as it melts way below the liquidus
of titanium and its commonly used alloys. And since silver and silver
solder will bonds to gold, I suspect that the two would be
compatible. But the trick here is to use a welding box, eliminate the
air and replace with a shielding gas. Airplane wings are brazed
together with a steel retort (I forgot which steel alloy is used, but
it must be a certain type to prevent expansion on heating). The
retort idea would be ideal for this project except that it would be
used only once. One of my professors in metallurgy at Montana Tech
was able to weld titanium just using a shielding gas, but I am not
sure exactly how he did it (and he recently passed away). I have
brazed many titanium glasses frames without a shielding gas, but
sometimes it won’t work at all. Since this rarely comes up in my
shop, I have resisted getting shielding gas since most of our
soldering/brazing/welding do not require it.

Jeffrey: let us know if you have any success (or failure) with this!

Chris van Laer
http://www.asterism-services.com


#7

I recently cast a part of one of my large pieces of pottery.

The wax with sprues weighted 59 grams. The final casting with sprues
and sprue button weighted 823 grams.

There was only 1/4 inches between the flask and the wax with only
1.5 inches of investment above the wax.

The silver was melted in a large Electro Melt furnace.

I have cast many of these large creations without failures.

Check out my blog on the subject.
http://leessilver.ganoksin.com/blogs/

Lee Epperson


#8

I use a pulse arc welder and have good results attaching gold to
titanium. I have argon gas connected so that a puff of argon comes
out around the welding tip. It helps alot but what has been the
biggest benefit of all has been Firescoff spray flux/coating. Its
kindof expensive for a bottle but it has definitly proved its worth.
My employee bought some at a trade show and after I saw the results,
I was easily persuaded to include it into the shops regular supply
linup. Its original use is for gold and silver soldering but does
wonders on titanium as well.

I get an average of 5-6 peeps a week come in with eyeglasses made of
titanium(most nowadays) and have devised a number of ways to repair.
At $20, and up, for a 5 minute job, its been well worth it. Titanium
presents challenges in getting a strong weld and one of the ways I
sometimes strengthen a precariuos joint is with a piece of 14k wire.
Eyeglasses have some unusual joint stresses, especially as someone
is spreading them as they put them on their face, so repair joints
need to be particularly strong.

Ed


#9
Might it be possible to drill a small cavity in the titanium, then
use a laser or pulse welder to fill it with white gold, then
solder to that? I've used my pulse welder to get gold to stick to
titanium, although I wouldn't trust it's strength for a joint. But
filling a small depression, there's no appreciable stress on it for
something like an earring post. 

Yes you are in effect TIG brazing with the PUK or other pulse arc
welders. I have done a set of experiments and photographed them on
trying to solder titanium with a torch and the only successful one
was the use of the PUK to weld /braze a small dot of gold to the
titanium and then torch braze to the gold. I am putting them into my
blog and it should be updated tonight or tomorrow some time at
http://binnion.ganoksin.com/blogs/

Regards
Jim

James Binnion
James Binnion Metal Arts


#10

Chris,

There are certainly titanium parts on many aircraft and some are
brazed assemblies. The SR 71 was a titanium airframe aircraft but
they were horridly expensive to make are no longer produced.I don’t
know if any of their wing structures were brazed but certainly other
parts of its structure were brazed. Titanium is so difficult to work
that its use is restricted to places where no other material will do
the job. That is why the vast majority of airplane wings are aluminum
or in the case of the newest ones graphite composites as these
materials are more than adequate to the task and they are riveted and
or glued together.

As for intermetallics titanium forms two intermetallic compounds with
silver TiAg And Ti2Ag and it forms even more with copper (seven)
which is the other main component to silver solders. These
intermetallics do occur in the brazed joints. That being said you
can indeed braze Ti with silver solder in a argon or vacuum furnace
just not with a torch. Regular silver solders are a problem though
because of brittle joints from the copper titanium intermetallics and
joint erosion again caused by the copper. Pure silver is acceptable
as a braze filler metal or a 95% silver 5% aluminum braze alloy.
There are a whole host of braze alloys for titanium if you are
brazing in argon or vacuum. Sure you can try to glop on some solder
and might get some kind of weak joint but it will not wet the
titanium. This is why titanium is often used for solder pics, it is
damn hard to get the solder to stick to it.

You need a highly reactive solder and flux to deal with torch
brazing of titanium because of Ti’s affinity for oxygen you need some
very reactive materials to strip the oxides from the joint. That is
why the braze alloys for Ti torch work are aluminum or magnesium
based and the fluxes contain fluoride chloride and lithium compounds.

I spent part of the afternoon making up some samples of attempts at
brazing titanium with a torch. None of them were successful I did
make a brazed joint with a TIG brazed silver solder puddle that I
then brazed a earpost on it and it cracked as soon as I tried to flex
it due to the intermetallic issue. I also did another example using
the PUK to weld a small dot of gold onto the titanium and then torch
brazed an earpost on it which was quite successful but it did
require the use of a PUK to make the gold pad to braze to.

I am writing a blog post with pictures of these experiments and it
will be done sometime tonight or tomorrow morning so if you would
like to see the results you can go to

http://binnion.ganoksin.com/blogs/

tomorrow some time and look at it.

Jim

James Binnion
James Binnion Metal Arts


#11
Titanium is routinely brazed (soldered) in argon and vacuum
atmosphere furnaces. It is occasionally brazed with a torch but... 

Thanks James, I was unaware of the exotic methods used in the
aerospace industry and was really thinking only of the type of torch
brazing normally employed by bench jewellers.

Regards, Gary Wooding