Platinum & Titanium

I don't have much experience with platinum, but I have made a few things.
Because of the high temperatures involved, up till now I've managed to
solder components by relying on gravity to hold them in position, but now
I've got a commission that needs something more. I figured that reverse
action tweezers would meet my requirements but the steel ones I have would
melt before the solder, so I purchased a pair made of titanium. Just prior
to using them I received an email from Cookson's that gave some advice about
working with platinum, in which it said to use a tungsten pick for platinum,
not titanium. Why not? I don't use a pick, so will my titanium tweezers be
OK?

--

Regards, Gary Wooding
To reply, change 'feet' to 'foot' in my address)


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Wooding wrote:
I don't have much experience with platinum, but I have made a few things.
Because of the high temperatures involved, up till now I've managed to
solder components by relying on gravity to hold them in position, but now
I've got a commission that needs something more. I figured that reverse
action tweezers would meet my requirements but the steel ones I have would
melt before the solder, so I purchased a pair made of titanium. Just prior
to using them I received an email from Cookson's that gave some advice about
working with platinum, in which it said to use a tungsten pick for platinum,
not titanium. Why not? I don't use a pick, so will my titanium tweezers be
OK?


No, most definitely not! Use Tungsten tweezers, or steel tweezers with Tungsten
tips. Quartz tipped or ceramic tipped tweezers are also fine.
(http://www.ottofrei.com/store/custom...e.php?cat=1321)

Do not use Titanium. Titanium will oxidize quite badly and will contaminate
your work.

And, do use a pick.

Do not forget to use adequate eye protection!

Abrasha
http://www.abrasha.com

"Abrasha" wrote in message
...
Wooding wrote:
I don't have much experience with platinum, but I have made a few
things.
Because of the high temperatures involved, up till now I've managed to
solder components by relying on gravity to hold them in position, but
now
I've got a commission that needs something more. I figured that reverse
action tweezers would meet my requirements but the steel ones I have
would
melt before the solder, so I purchased a pair made of titanium. Just
prior
to using them I received an email from Cookson's that gave some advice
about
working with platinum, in which it said to use a tungsten pick for
platinum,
not titanium. Why not? I don't use a pick, so will my titanium
tweezers be
OK?


No, most definitely not! Use Tungsten tweezers, or steel tweezers with
Tungsten
tips. Quartz tipped or ceramic tipped tweezers are also fine.
(http://www.ottofrei.com/store/custom...e.php?cat=1321)

Do not use Titanium. Titanium will oxidize quite badly and will
contaminate
your work.

And, do use a pick.

Do not forget to use adequate eye protection!

Abrasha
http://www.abrasha.com

Titanium's melting point is only 50 degrees above the melting point of
platinum (3,222 degrees). Seems like you might melt the tweezers right along
with the platinum. Tungsten doesn't melt until 6,170 degrees.

D. R. Crawford wrote:


Titanium's melting point is only 50 degrees above the melting point of
platinum (3,222 degrees).

That is irrelevant in this case. And your numbers are wrong.

Titanium's melting point is BELOW that of platinum at 3020 degrees F (1660
degrees C plus or minus 10 degrees)
http://www.chemistrydata.com/Element...ting_point.htm
You've got Platinum right
(http://www.chemistrydata.com/Element...ting_point.htm)

You can also check here. Slightly different figures.
http://www.webelements.com/webelemen...t/Ti/heat.html (3215 degrees)
http://www.webelements.com/webelemen...t/Pt/heat.html (3034 degrees)


Seems like you might melt the tweezers right along
with the platinum.

No he won't, not even close. He is not melting, he is soldering, which takes
place well below the melting point of both metals.

Here is a list of platinum solder melting points from David Fell's site.
http://www.dhfco.com/pages/platinum_solder.html

Besides the fact that your numbers are incorrect, the above melting points are
for the pure forms of the mentioned metals. Platinum alloys do not melt at the
temperature you state. They melt at higher temperatures. Look he
http://www.dhfco.com/pages/platinum_temp.html

The same is true for titanium alloys. It depends entirely on the used alloy,
what the melting temperature is.

Abrasha
http://www.abrasha.com

On Sun, 31 Oct 2004 13:15:56 -0800, in hõ Abrasha wrote:

Seems like you might melt the tweezers right along
with the platinum.

No he won't, not even close. He is not melting, he is soldering, which takes
place well below the melting point of both metals.

Oh, I guess I'll disagree on that one Abrasha. Not the part about platinum solders
melting well below either platinum, or titanium tweezers. but I'll suggest that it's
still uncomfortably close to simply melting the tweezers. it's not the temp that the
solder reaches, but the temp the tweezers reach, that matters here, and since
titanium is a rather poor conductor of heat, the tips of the tweezers, in the torch
flame that's heating the platinum and it's solder, can very easily be accidentally
heated to quite hot enough to melt the tweezers. I know. I've done it more than
once, the few times I accidentally grabbed titanium tweezers instead of the tungsten
ones.... And actually, the titanium never really melts. Just burns. the moment it
starts to melt, you get this crackling sizzling sound and a very bright flare of
light, and suddenly your tweezer tips are in serious need of reshaping. Gets your
attention...

:-)

Peter

Well, I certainly got your motor revved up, didn't I, Abrasha. I didn't
expect to generate quite so much heated controversy (pun intended) with only
three short sentences. Anyway, as far as titanium's melting point is
concerned, you're quite right---I looked it up and it is indeed 3,020
degrees. I must have accidentally inserted another "2" in the string of
numbers.

I'm glad you agree with me about platinum at least, but if you really want
to be picky about things then I have to tell you that when you say "He is
not melting, he is soldering" he is in fact not soldering at all, since if
it takes place above 800 degrees, it is actually brazing, not soldering.
That's what Tim McCreight says anyway, and I'm sure he wouldn't lie to us.

My original intent with those three short sentences was just to add
something in the nature of a wry footnote to something you had already
settled quite well with your advice about tungsten, with perhaps just the
slightest tinge of humor in the notion that the titanium tweezers might melt
before the platinum. I really didn't intend to set anybody off, and I do
apologize if I made you feel challenged somehow.

"Abrasha" wrote in message
...
D. R. Crawford wrote:


Titanium's melting point is only 50 degrees above the melting point of
platinum (3,222 degrees).

That is irrelevant in this case. And your numbers are wrong.

Titanium's melting point is BELOW that of platinum at 3020 degrees F (1660
degrees C plus or minus 10 degrees)
http://www.chemistrydata.com/Element...ting_point.htm
You've got Platinum right
(http://www.chemistrydata.com/Element...ting_point.htm)

You can also check here. Slightly different figures.
http://www.webelements.com/webelemen...t/Ti/heat.html (3215
degrees)
http://www.webelements.com/webelemen...t/Pt/heat.html (3034
degrees)


Seems like you might melt the tweezers right along
with the platinum.

No he won't, not even close. He is not melting, he is soldering, which
takes
place well below the melting point of both metals.

Here is a list of platinum solder melting points from David Fell's site.
http://www.dhfco.com/pages/platinum_solder.html

Besides the fact that your numbers are incorrect, the above melting points
are
for the pure forms of the mentioned metals. Platinum alloys do not melt
at the
temperature you state. They melt at higher temperatures. Look he
http://www.dhfco.com/pages/platinum_temp.html

The same is true for titanium alloys. It depends entirely on the used
alloy,
what the melting temperature is.

Abrasha
http://www.abrasha.com

Well, apart from the replies in this newsgroup, I've also had a few by
direct email. All advise against the use of titanium, but whilst Googling
for tungsten or ceramic tipped tweezers (for which, by the way, I could find
nothing in UK) I found the following statements in the Shore site at
http://shorinternational.com/TweezersSlide.htm

************************************************** ************
Soldering Tweezers

The soldering tweezers shown here are all heavy duty. Many tweezers from
other Shor web pages can also be used for soldering (for example, the black
oxidized AA tweezers are excellent for this purpose). In addition, for
platinum soldering, you will want to use titanium tweezers.

Tweezer Metals:
The chart below shows general property relationships among the various
metals used in the manufacturing of tweezers. In addition, note that the
points of the harder metals will wear longer and are less subject to
bending. The softer metals will not scratch delicate parts and usually have
additional desirable properties such as being non-magnetic, etc. Titanium
has a very high melting temperature and is commonly used when soldering
platinum.
************************************************** *************

What do you think of that?

--

Regards, Gary Wooding
To reply, change 'feet' to 'foot' in my address)
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Peter W.. Rowe, wrote:
On Sun, 31 Oct 2004 13:15:56 -0800, in hõ Abrasha wrote:


Seems like you might melt the tweezers right along
with the platinum.

No he won't, not even close. He is not melting, he is soldering, which takes
place well below the melting point of both metals.


Oh, I guess I'll disagree on that one Abrasha. Not the part about platinum solders
melting well below either platinum, or titanium tweezers. but I'll suggest that it's
still uncomfortably close to simply melting the tweezers. it's not the temp that the
solder reaches, but the temp the tweezers reach, that matters here, and since
titanium is a rather poor conductor of heat, the tips of the tweezers, in the torch
flame that's heating the platinum and it's solder, can very easily be accidentally
heated to quite hot enough to melt the tweezers. I know. I've done it more than
once, the few times I accidentally grabbed titanium tweezers instead of the tungsten
ones.... And actually, the titanium never really melts. Just burns. the moment it
starts to melt, you get this crackling sizzling sound and a very bright flare of
light, and suddenly your tweezer tips are in serious need of reshaping. Gets your
attention...

:-)

Peter
Morning Peter,
So , what would I do if I had the priviledge of working platinum and
needed to use tungsten tweezers or some means of holding the parts to be
fused with tungsten.
I dont know what tungsten tweezers cost but theres a very economical
form of tungsten rod available from most welding supply houses. Its the
rod in 1.6mm 2.4mm, and 4.5mm by 150mm long round rod used in tig
torches as the electrode rod in the torch. Costing only a few bucks per rod.
Now its grindable to a point, thats the way you use it in the tig
torch so it should be possible to shape the rod ends to suit the job in
hand. Now one would need to modify a pair of tweezers to take these
tungsten rods. Id use the collet principle soldered onto a cut off pair
of surgical tweezers, as these come in all sorts of sizesand are
stainless steel, easy to braze fittings thereon. The tungsten might
just be brazeable as the tungsten tipped tools are fixed this way for
lathe turning tools.
Whats the opinion from you other pro,s on this?

On , in ?? Ted Frater wrote:

Morning Peter,
So , what would I do if I had the priviledge of working platinum and
needed to use tungsten tweezers or some means of holding the parts to be
fused with tungsten.
I dont know what tungsten tweezers cost

commercially made ones tend to be pricey. Most that i've seen use tungsten carbide,
rather than the TIG electrode form you mention, which I generally use in preference,
simply due to low cost and easier working. I do also keep carbide blanks around for
burnishers. My first pair of soldering tweezers made especially for platinum work
were pretty much as you describe, a pair of stainless soldering tweezers, the kind
with the phenolic pads on the handles for insulation. (the plain ones, not the cross
lock type) The main body of the tips are trimmed short, and a couple thicker steel
blocks affixed with small bolts. The ends are drilled to accept lengths of carbide
or tungston rod, to be held in with set screws. These came with carbide tips, and
I've never needed to change them. I did eventually got annoyed with the way heating
and cooling kept loosening those bolts, making the tips move unexpectedly, so I laser
welded those blocks to the tweezer arms. Now they're a much used tool. I've
another pair I made myself, just by laser welding tungsten TIG rod ends to soldering
tweezers. Found out after the fact that the phenolic insulating pads were very good
ideas indeed, so I jury rigged something of the sort on these too. I've also got a
GRS soldering station, which combines a six inch square soldering surface
(non-asbestos board) with a pair of sturdy tweezers that clamp on either side, and
the whole affair can mount on the fixture that usually holds a bench pin. handy when
space on the bench is in short supply. The tips on those tweezers can optionally be
had as carbide, rather than the standard steel, for working platinum. I've
discovered, though, that this commercially made solution is less satisfactory.
Carbide happens to be a rather good heat conductor, and at the temps one is soldering
platinum, those somewhat short carbide tips quickly heat up a LOT. Even though the
bodies of the tweezers are quite heavy and sturdy, they can get enough transmitted
heat to get hot enough to cause a painful burn when one goes to unclip one's work
from the tweezer, and once it even got hot enough to take the temper out of the
spring that operates the tweezer. The things look good, but are not a well
engineered design from a thermal conductivity standpoint, being simply too short and
heavy. I did, eventually, work out a way to add insulation to these tweezer handles
too, to avoid burning fingers, but the springs are still vulnerable. Mostly, I use
the hand held tweezers previously described, for that reason, and save the silly GRS
tweezers for lower temperature work

Peter

"Wooding" wrote in message
...
Well, apart from the replies in this newsgroup, I've also had a few by
direct email. All advise against the use of titanium, but whilst Googling
for tungsten or ceramic tipped tweezers (for which, by the way, I could
find
nothing in UK) I found the following statements in the Shore site at
http://shorinternational.com/TweezersSlide.htm

************************************************** ************
Soldering Tweezers

The soldering tweezers shown here are all heavy duty. Many tweezers from
other Shor web pages can also be used for soldering (for example, the
black
oxidized AA tweezers are excellent for this purpose). In addition, for
platinum soldering, you will want to use titanium tweezers.

Tweezer Metals:
The chart below shows general property relationships among the various
metals used in the manufacturing of tweezers. In addition, note that the
points of the harder metals will wear longer and are less subject to
bending. The softer metals will not scratch delicate parts and usually
have
additional desirable properties such as being non-magnetic, etc. Titanium
has a very high melting temperature and is commonly used when soldering
platinum.
************************************************** *************

What do you think of that?

I know its bad form to reply to my own posts, but concluded that the lack
of response to this one
was due to my last line being missinterpreted as meaning 'this proves you
are wrong'. That wasn't the intent - I really wanted an opinion on the
statements in Shor's advert.

--

Regards, Gary Wooding
To reply, change 'feet' to 'foot' in my address)




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