[TheForge] welding 304 Stainless

Wed Feb 27 21:23:01 2002

        Mike,  Either process will work(mig or tig).  The nice thing about
Tig is the control of the distortion as Stainless is difficult to keep
straight.  308 wire is for welding general stainless parts.  309 is for
dissimilar metals or pressure situations like pipe.  I'd V the parts, tig
them at four points to get the alignment, then weld in the four quadrants.
The tri gas works well. Another trick if these are going to hold weight or
need some strength in the wind, etc..........is to back gas the parts so the
weld does not "sugar" or "crystalize" on the back side(inside of the pipe).
A hose T'd off to keep the tube cavity purged with gas will eliminate this.
Keep the heat as low as possible to get good welds and not burn any of the
chrome and nickle out of the tubing or it will be the first place to
tarnish, bleed or rust.  It is usually the edges of the welds(weld affected
zone) that will come thru and show rust as things tend to precipitate to
that area while welding to cause this.
        What ever you use to grind, level the surface, and polish out to
match.........make sure you haven't used them on steel products before, or
your project will rust.  I take 60, 80, 120 grit blending (flap) wheels,
then go to the scotchbrite pads to finish the blend or polish.  Same thing
applies to any wire brushing.........keep it a stainless brush, and it
should not have been used on steel priviously.
        Obviously a piece of stainless angle iron helps jiging things to
keep it straight as well as not puting any steel on the surface of the
stainless.  I've also used aluminum as it grabs the parts well and doesn't
transfer like steel.  The clamps I've used have had little pieces of
cardboard(posterboard like) to keep the scratches down from the clamps and
hence less clean up and plolishing.
        I've done many boat fixtures(pulpits, pushpits, biminy tops,
ladders, diving platforms, etc) with 316 stainless and had good luck with
the finishing techniques mentioned above with pretty good luck.

Ralph Sproul - Bear Hill Blacksmith
Webster, NH


----- Original Message -----
From: "Mike Wolfe" <[email protected]>
To: <[email protected]>; <[email protected]>
Sent: Wednesday, February 27, 2002 11:18 AM
Subject: [TheForge] welding 304 Stainless


> I need to weld 1 /12 dia. schedule 40 stainless tube together.
> I can use Mig with 308 0r 309 wire with TRI mix gas or I can use Tig.
> Also I have to finish the joint so that it blends with the rest of the
> tube.
> I am not sure if the supplied tubes are Satin finish or Mill finish....
> I am aware of the 3M products for blending stainless..
> Any Ideas or past experiences would be helpful.
> Thanks Mike Wolfe
>
> http://www.designsiniron.com
>
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