On Wed, 19 Jul 2017 18:55:12 +0800, Trumble
wrote:
On 19-Jul-17 6:19 PM, Gunner Asch wrote:
On Wed, 19 Jul 2017 18:01:47 +0800, Trumble
wrote:
On 18-Jul-17 7:19 PM, Trumble wrote:
I've never TIG welded - only amateur MIG & stick welding......
As part of an assembly process would the following be possible:
I've got a 304 stainless steel tube with some electronics embedded in
polyurethane inside it.
I want to put a 304 stainless cap on the end of the tube capable of
handling say 20 kg pulling force.
When fitted to the end of the tube the gap from the cap to the
polyurethane potting material will be 1/32"
How much heat would spot TIG'ing the cap onto the tube introduce to the
assembly?
Cool it with a damp cloth immediately after welding?
SPOT TIG HERE
|
\/
======================================|====\
| |==== \
| | |
POLYURETHANE POTTING | | O |
COMPOUND | | |
| |==== /
======================================|====/
^
|
SPOT TIG HERE
|---Tube 1/2" OD x 1/16 wall----------|-cap-|
Should I be looking at threading the cap into the end of the tube?
Many thanks for the suggestions guys.
It looks like TIG might be iffy.
Threading the cap and tube would be ideal but is a lot of mucking around
for this job which I want to keep cheep.
I like the sound of the Loctite 638. I think I'll try it out.
There's always lots of invaluable advice here, thanks again.
Be sure to have 5-15 thousands clearance between the parts. A snug fit
will be NFG if it wipes off the glue when you assemble it.
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Thanks - that's something I hadn't thought of.
Gunner is on the high end of that clearance. 638 will fill moderate
gaps -- and, as Gunner said, it needs some gap -- but it loses bulk
strength with clearances over 0.010 in. Keep it around 0.005 if you
can.
Otherwise, it's made specifically for cylindrical fits like your
project, and it's quite strong. Follow the instructions; it's an
anaerobic acrylic, and it's not entirely intuitive. It cures in the
*absence* of air. The bottle it comes in actually is porous to air,
which keeps it from curing in the bottle.
--
Ed Huntress