Had another chat with the glass bead maker that wants me to fabricate
some tooling . She needs some mandrels made that are a piece of tungsten
rod welded/brazed to a stainless steel handle . The join is not subject
to the full heat of molten glass . Am I right in assuming that a TIG
torch set on DCEN will melt and fuse these two metals without filler ?
What filler is recommended ? I have on hand 308 309/309l , and some 312
in various sizes . I also have some ER70S2 on hand and some Invar42
nickel/iron filler . She indicates that these must be pretty straight ,
no wobbles when they are spun or rolled across a flat surface . I'm
thinking a long vee block with a cutout in the middle , maybe a spring
on one end to keep things pushed together . We're getting into uncharted
territory here for me , I'm open to suggestions - that pertain to the
task at hand , please .

--
Snag
Yes , I'm old
and crochety .
Get off my lawn !

"Terry Coombs" wrote in message
news
Had another chat with the glass bead maker that wants me to
fabricate some tooling . She needs some mandrels made that are a
piece of tungsten rod welded/brazed to a stainless steel handle .
The join is not subject to the full heat of molten glass . Am I
right in assuming that a TIG torch set on DCEN will melt and fuse
these two metals without filler ? What filler is recommended ? I
have on hand 308 309/309l , and some 312 in various sizes . I also
have some ER70S2 on hand and some Invar42 nickel/iron filler . She
indicates that these must be pretty straight , no wobbles when they
are spun or rolled across a flat surface . I'm thinking a long vee
block with a cutout in the middle , maybe a spring on one end to
keep things pushed together . We're getting into uncharted territory
here for me , I'm open to suggestions - that pertain to the task at
hand , please .

--
Snag
Yes , I'm old
and crochety .
Get off my lawn !


Perhaps you could explain to her the advantages of a press fit in a
bored hole.

On Wed, 20 Jun 2018 06:36:20 -0500, Terry Coombs
wrote:

Had another chat with the glass bead maker that wants me to fabricate
some tooling . She needs some mandrels made that are a piece of tungsten
rod welded/brazed to a stainless steel handle . The join is not subject
to the full heat of molten glass . Am I right in assuming that a TIG
torch set on DCEN will melt and fuse these two metals without filler ?
What filler is recommended ? I have on hand 308 309/309l , and some 312
in various sizes . I also have some ER70S2 on hand and some Invar42
nickel/iron filler . She indicates that these must be pretty straight ,
no wobbles when they are spun or rolled across a flat surface . I'm
thinking a long vee block with a cutout in the middle , maybe a spring
on one end to keep things pushed together . We're getting into uncharted
territory here for me , I'm open to suggestions - that pertain to the
task at hand , please .
You will not be able to TIG weld the tungsten to the stainless with
any reasonable success. But you can silver braze to tungsten easily.
And with silver brazing, AKA silver soldering, you can get the two
pieces quite coaxial. Drill a hole that is about .500" deep and a
light press fit for the tungsten into the stainless. Then open up the
hole about .004" over the diameter of the tungsten but only about
..190" deep. Grind or file a small flat on the tungsten that is about
..550" long. The flat acts as a vent to allow any air trapped in the
hole to escape. So it doesn't need to be very big.Then press the
tungsten into the SS and silver solder it in. Of course make sure
everything is clean.
Eric

On Wed, 20 Jun 2018 06:36:20 -0500, Terry Coombs
wrote:

Had another chat with the glass bead maker that wants me to fabricate
some tooling . She needs some mandrels made that are a piece of tungsten
rod welded/brazed to a stainless steel handle . The join is not subject
to the full heat of molten glass . Am I right in assuming that a TIG
torch set on DCEN will melt and fuse these two metals without filler ?
What filler is recommended ? I have on hand 308 309/309l , and some 312
in various sizes . I also have some ER70S2 on hand and some Invar42
nickel/iron filler . She indicates that these must be pretty straight ,
no wobbles when they are spun or rolled across a flat surface . I'm
thinking a long vee block with a cutout in the middle , maybe a spring
on one end to keep things pushed together . We're getting into uncharted
territory here for me , I'm open to suggestions - that pertain to the
task at hand , please .


Tungsten cannot be "welded". It can be brazed..and it can be "silver
soldered"..but it really cannot be "welded"..


https://www.brazing.com/products/Bra...ingFluxes.aspx

http://www.carbideprocessors.com/pag...n-carbide.html

Im sure others here have done this far more than I have...Im looking
forwards to their responses.
Its an interesting problem!



---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On Wednesday, June 20, 2018 at 7:36:16 AM UTC-4, Terry Coombs wrote:
Had another chat with the glass bead maker that wants me to fabricate
some tooling . She needs some mandrels made that are a piece of tungsten
rod welded/brazed to a stainless steel handle . The join is not subject
to the full heat of molten glass . Am I right in assuming that a TIG
torch set on DCEN will melt and fuse these two metals without filler ?
What filler is recommended ? I have on hand 308 309/309l , and some 312
in various sizes . I also have some ER70S2 on hand and some Invar42
nickel/iron filler . She indicates that these must be pretty straight ,
no wobbles when they are spun or rolled across a flat surface . I'm
thinking a long vee block with a cutout in the middle , maybe a spring
on one end to keep things pushed together . We're getting into uncharted
territory here for me , I'm open to suggestions - that pertain to the
task at hand , please .

--
Snag
Yes , I'm old
and crochety .
Get off my lawn !

I think Eric has the solution.

One more suggestion depends on the diameters of the tungsten and the stainless. If there is enough meat , you could use a set screw to hold the tungsten in the stainless.

You can get stainless set screws on AliExpess at a low price, but they will be metric.

Dan

On 6/20/2018 10:25 AM, Jim Wilkins wrote:
"Terry Coombs" wrote in message
news
Had another chat with the glass bead maker that wants me to
fabricate some tooling . She needs some mandrels made that are a
piece of tungsten rod welded/brazed to a stainless steel handle .
The join is not subject to the full heat of molten glass . Am I
right in assuming that a TIG torch set on DCEN will melt and fuse
these two metals without filler ? What filler is recommended ? I
have on hand 308 309/309l , and some 312 in various sizes . I also
have some ER70S2 on hand and some Invar42 nickel/iron filler . She
indicates that these must be pretty straight , no wobbles when they
are spun or rolled across a flat surface . I'm thinking a long vee
block with a cutout in the middle , maybe a spring on one end to
keep things pushed together . We're getting into uncharted territory
here for me , I'm open to suggestions - that pertain to the task at
hand , please .

--
Snag
Yes , I'm old
and crochety .
Get off my lawn !

Perhaps you could explain to her the advantages of a press fit in a
bored hole.


Â* Or a simple collet ...

--
Snag
Yes , I'm old
and crochety .
Get off my lawn !

On 6/20/2018 12:16 PM, Gunner Asch wrote:
On Wed, 20 Jun 2018 06:36:20 -0500, Terry Coombs
wrote:

Had another chat with the glass bead maker that wants me to fabricate
some tooling . She needs some mandrels made that are a piece of tungsten
rod welded/brazed to a stainless steel handle . The join is not subject
to the full heat of molten glass . Am I right in assuming that a TIG
torch set on DCEN will melt and fuse these two metals without filler ?
What filler is recommended ? I have on hand 308 309/309l , and some 312
in various sizes . I also have some ER70S2 on hand and some Invar42
nickel/iron filler . She indicates that these must be pretty straight ,
no wobbles when they are spun or rolled across a flat surface . I'm
thinking a long vee block with a cutout in the middle , maybe a spring
on one end to keep things pushed together . We're getting into uncharted
territory here for me , I'm open to suggestions - that pertain to the
task at hand , please .

Tungsten cannot be "welded". It can be brazed..and it can be "silver
soldered"..but it really cannot be "welded"..


https://www.brazing.com/products/Bra...ingFluxes.aspx

http://www.carbideprocessors.com/pag...n-carbide.html

Im sure others here have done this far more than I have...Im looking
forwards to their responses.
Its an interesting problem!



---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

Â* This project uses metallic tungsten , not tungsten carbide . If my
TIG welder can get an arc hot enough to ball the tungsten , I'm pretty
sure it can melt it on the positive side of a DC arc .

--
Snag
Yes , I'm old
and crochety .
Get off my lawn !

On 20/06/18 12:36, Terry Coombs wrote:
Had another chat with the glass bead maker that wants me to fabricate
some tooling . She needs some mandrels made that are a piece of
tungsten rod welded/brazed to a stainless steel handle . The join is
not subject to the full heat of molten glass . Am I right in assuming
that a TIG torch set on DCEN will melt and fuse these two metals
without filler ? What filler is recommended ? I have on hand 308
309/309l , and some 312 in various sizes . I also have some ER70S2 on
hand and some Invar42 nickel/iron filler . She indicates that these
must be pretty straight , no wobbles when they are spun or rolled
across a flat surface . I'm thinking a long vee block with a cutout in
the middle , maybe a spring on one end to keep things pushed together
. We're getting into uncharted territory here for me , I'm open to
suggestions - that pertain to the task at hand , please .

How about the mandrel pin vice listed here
https://www.arrowsprings.com/html/holding_tools.html about 2/3 the way
down the page.

On Wednesday, June 20, 2018 at 3:05:08 PM UTC-4, Terry Coombs wrote:
On 6/20/2018 12:16 PM, Gunner Asch wrote:
On Wed, 20 Jun 2018 06:36:20 -0500, Terry Coombs
wrote:

Had another chat with the glass bead maker that wants me to fabricate
some tooling . She needs some mandrels made that are a piece of tungsten
rod welded/brazed to a stainless steel handle . The join is not subject
to the full heat of molten glass . Am I right in assuming that a TIG
torch set on DCEN will melt and fuse these two metals without filler ?
What filler is recommended ? I have on hand 308 309/309l , and some 312
in various sizes . I also have some ER70S2 on hand and some Invar42
nickel/iron filler . She indicates that these must be pretty straight ,
no wobbles when they are spun or rolled across a flat surface . I'm
thinking a long vee block with a cutout in the middle , maybe a spring
on one end to keep things pushed together . We're getting into uncharted
territory here for me , I'm open to suggestions - that pertain to the
task at hand , please .

Tungsten cannot be "welded". It can be brazed..and it can be "silver
soldered"..but it really cannot be "welded"..


https://www.brazing.com/products/Bra...ingFluxes.aspx

http://www.carbideprocessors.com/pag...n-carbide.html

Im sure others here have done this far more than I have...Im looking
forwards to their responses.
Its an interesting problem!



---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

Â* This project uses metallic tungsten , not tungsten carbide . If my
TIG welder can get an arc hot enough to ball the tungsten , I'm pretty
sure it can melt it on the positive side of a DC arc .

--
Snag
Yes , I'm old
and crochety .
Get off my lawn !

Bad juju. Tungsten is very difficult to weld, even to itself. It oxidizes rapidly at 950 deg. F and it's prone to cracking. It forms nasty, brittle intermetallics with some brazing metals. In my mixed-metal laser welding references, I find nothing that suggests it can be welded to steel of any kind, and nearly all of the mixed-metal commercial welding today is done with lasers.

It can be silver- or gold-brazed in a protective atmosphere. But the authorities recommend press- or shrink-fitting or mechanical joining (bolts, etc.) if the configuration will allow it.

Good luck.

--
Ed Huntress

On Wed, 20 Jun 2018 13:46:47 -0500, Terry Coombs
wrote:

On 6/20/2018 10:25 AM, Jim Wilkins wrote:
We're getting into uncharted territory
here for me , I'm open to suggestions - that pertain to the task at
hand , please .

Perhaps you could explain to her the advantages of a press fit in a
bored hole.


* Or a simple collet ...

I'm a glass blower so maybe I can add some useful content.

The "advantage" of a press fit is that when at operating temperature,
the tungsten will fall out. SS has a pretty high temco; Platinum
almost zero. Pt is near enough to quartz that Pt and quartz can be
fused together to make gas-tight seals.

The bored hole/sweated fit is a good idea except that the glass artist
will want the handle to be a small a diameter as possible.

The best way to do it is just a simple silver-soldered butt joint.

You should be able to get it close enough on the runout with
hand-holding. If not, the V-block idea will work well.

Don't try TIG - much too hot and will sublime constituents of the
silver solder. A MAPP gas torch is fine. I do mine with an
oxy-hydrogen burning Mini-Torch just because I already had it. That
is too hot up in the flame cone but the penumbra of the flame is just
perfect.

John
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address

On Wed, 20 Jun 2018 14:05:54 -0500, Terry Coombs
wrote:

On 6/20/2018 12:16 PM, Gunner Asch wrote:
On Wed, 20 Jun 2018 06:36:20 -0500, Terry Coombs
wrote:

Had another chat with the glass bead maker that wants me to fabricate
some tooling . She needs some mandrels made that are a piece of tungsten
rod welded/brazed to a stainless steel handle . The join is not subject
to the full heat of molten glass . Am I right in assuming that a TIG
torch set on DCEN will melt and fuse these two metals without filler ?
What filler is recommended ? I have on hand 308 309/309l , and some 312
in various sizes . I also have some ER70S2 on hand and some Invar42
nickel/iron filler . She indicates that these must be pretty straight ,
no wobbles when they are spun or rolled across a flat surface . I'm
thinking a long vee block with a cutout in the middle , maybe a spring
on one end to keep things pushed together . We're getting into uncharted
territory here for me , I'm open to suggestions - that pertain to the
task at hand , please .

Tungsten cannot be "welded". It can be brazed..and it can be "silver
soldered"..but it really cannot be "welded"..


https://www.brazing.com/products/Bra...ingFluxes.aspx

http://www.carbideprocessors.com/pag...n-carbide.html

Im sure others here have done this far more than I have...Im looking
forwards to their responses.
Its an interesting problem!



---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

* This project uses metallic tungsten , not tungsten carbide . If my
TIG welder can get an arc hot enough to ball the tungsten , I'm pretty
sure it can melt it on the positive side of a DC arc .
You certainly can melt the tungsten with a TIG welder but welding it
to the SS is the problem. If you do go with silver solder the tungsten
should be covered with flux to avoid excessive oxidation.
Eric

On Wed, 20 Jun 2018 20:14:28 +0100, David Billington
wrote:

How about the mandrel pin vice listed here
https://www.arrowsprings.com/html/holding_tools.html about 2/3 the way
down the page.

Too short for the job - will burn the fingers quickly. Probably won't
work after the first heat because the fingers are de-tempered.

Glass workers have had a couple thousand years to perfect their tools.
It is VERY difficult to improve on what is traditional. I know, I've
tried.

Graphite is the traditional mandrel material but it oxidizes quickly.
Tungsten was a great improvement but it must be coated with a release
substance because glass wets tungsten. The usual release material is
colloidal silica.
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address

On 20/06/18 22:44, Neon John wrote:
On Wed, 20 Jun 2018 20:14:28 +0100, David Billington
wrote:

How about the mandrel pin vice listed here
https://www.arrowsprings.com/html/holding_tools.html about 2/3 the way
down the page.
Too short for the job - will burn the fingers quickly. Probably won't
work after the first heat because the fingers are de-tempered.

Glass workers have had a couple thousand years to perfect their tools.
It is VERY difficult to improve on what is traditional. I know, I've
tried.

Graphite is the traditional mandrel material but it oxidizes quickly.
Tungsten was a great improvement but it must be coated with a release
substance because glass wets tungsten. The usual release material is
colloidal silica.
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address

Are you sure you looked at the correct item as it is mentioned as 6.5"
long and sold for holding the likes of tungsten rods for bead making. I
know you have responded to a post of mine before when I mentioned all
the bead makers I know seem to get on fine with stainless steel mandrels
and bead release which you mention is required even with tungsten.

"Terry Coombs" wrote in message
news
On 6/20/2018 10:25 AM, Jim Wilkins wrote:
"Terry Coombs" wrote in message
news
Had another chat with the glass bead maker that wants me to
fabricate some tooling . She needs some mandrels made that are a
piece of tungsten rod welded/brazed to a stainless steel handle .
The join is not subject to the full heat of molten glass . Am I
right in assuming that a TIG torch set on DCEN will melt and fuse
these two metals without filler ? What filler is recommended ? I
have on hand 308 309/309l , and some 312 in various sizes . I also
have some ER70S2 on hand and some Invar42 nickel/iron filler . She
indicates that these must be pretty straight , no wobbles when
they
are spun or rolled across a flat surface . I'm thinking a long vee
block with a cutout in the middle , maybe a spring on one end to
keep things pushed together . We're getting into uncharted
territory
here for me , I'm open to suggestions - that pertain to the task
at
hand , please .

--
Snag
Yes , I'm old
and crochety .
Get off my lawn !

Perhaps you could explain to her the advantages of a press fit in a
bored hole.


Or a simple collet ...

--
Snag

The simplest collet I know how to make is a male pipe thread on the
end of the hollow shaft, slit lengthwise after threading. The collet
closer nut is a drilled pipe cap.

Making a holder for an existing collet involves boring an internal
taper accurately or machining and hardening a tapered D drill or
reamer.

On Wed, 20 Jun 2018 13:46:47 -0500, Terry Coombs
wrote:

On 6/20/2018 10:25 AM, Jim Wilkins wrote:
"Terry Coombs" wrote in message
news
Had another chat with the glass bead maker that wants me to
fabricate some tooling . She needs some mandrels made that are a
piece of tungsten rod welded/brazed to a stainless steel handle .
The join is not subject to the full heat of molten glass . Am I
right in assuming that a TIG torch set on DCEN will melt and fuse
these two metals without filler ? What filler is recommended ? I
have on hand 308 309/309l , and some 312 in various sizes . I also
have some ER70S2 on hand and some Invar42 nickel/iron filler . She
indicates that these must be pretty straight , no wobbles when they
are spun or rolled across a flat surface . I'm thinking a long vee
block with a cutout in the middle , maybe a spring on one end to
keep things pushed together . We're getting into uncharted territory
here for me , I'm open to suggestions - that pertain to the task at
hand , please .

Perhaps you could explain to her the advantages of a press fit in a
bored hole.

* Or a simple collet ...

Even better!

-
When you radically activate on the side of the Left, you call
forth compensatory forces. And they're not under your control.
--Jordan B Peterson
Go Trump! MAGA

"Terry Coombs" wrote in message news
Had another chat with the glass bead maker that wants me to fabricate
some tooling . She needs some mandrels made that are a piece of tungsten
rod welded/brazed to a stainless steel handle . The join is not subject
to the full heat of molten glass . Am I right in assuming that a TIG
torch set on DCEN will melt and fuse these two metals without filler ?
What filler is recommended ? I have on hand 308 309/309l , and some 312
in various sizes . I also have some ER70S2 on hand and some Invar42
nickel/iron filler . She indicates that these must be pretty straight ,
no wobbles when they are spun or rolled across a flat surface . I'm
thinking a long vee block with a cutout in the middle , maybe a spring
on one end to keep things pushed together . We're getting into uncharted
territory here for me , I'm open to suggestions - that pertain to the
task at hand , please .


I am sure you already considered silvalloy silver brazing, but silvalloy
(expensive) is stronger than your regular plumbing solder and has a higher
melting point. (around 1600 F I think) Having said that I kind of liked
the idea of a press fit, and maybe even a mandrel fit in case differential
heat expansion doesn't allow for a press fit to workwell enough. Drill,
thread, and taper the end of a rod to hold the insert. Slide a threaded
closer up over the other end to clamp down on the insert. If they drop it
and break the insert it may be replaceable if heat cycling hasn't frozen the
threads.