Stainless welding...

Cracks in the Beemer's exhaust again (groan), and it needs an MOT. It's
gone by the bracket, and there is stainless reinforcing under the outer
sheet (where the two mounting bolts go in, so I reckon I might get away
with welding it, but...

I've got the Argon, but only 0.8mm stainless wire for the MIG. Casting
about on eBay etc., this seems the smallest wire easily found. Is it
sensible for thin stainless? I've got some to practice on (old flue from
the boiler), and my mild steel welding is OK-ish, but before spending
ages on more futile spatterings*, what doth t'team think?

Yes, I know this isn't uk.diy ...

Cheerth,

S.

*I suppose otherwise I need to find someone nearby with a TIG set.

 

Have a look at eBay item 220318147087 as an easier alternative. It is a
brazing product.

 

The message <>

If you're anywhere near Attleborough in Norfolk, Nick Paravanni on the
Bunns Bank industrial site on the Diss road is an ace SS welder.

He'll tell you anything you need to know.

 

Sadly not (Bristle, CUBA), but as it's now searchable, someone
may benefit in future!

Cheers,

S.

 

Thanks for that - duly 'watching' in eBay in case.

Trouble is it needs 1400 deg. and I don't have oxy-propane, although I
do have Mapp gas, which might work (with the right nozzle). Has to be
said though that the exhaust is quite brittle enough already*, so I
don't want to make matters worse.

Having cast around a bit more, it looks like 0.8mm is the smallest gauge
S/S wire easily available (as well as being wot I've got). I think I'll
experiment on the gash thin bits I've got, and see if I can tame the
welder. Annoyingly, it's a Clarke reel & doesn't say what grade of S/S
it's supposed to be for. Regrettably, I think this is the Christmas
project.

Cheers,

S.

*Wiki has this: "MAPP like all of the Liquified Petroleum gasses is not
appropriate for welding of steel, due to the high concentration of
hydrogen in the flame. The hydrogen infuses into the molten steel and
renders the welds brittle." <http://en.wikipedia.org/wiki/Mapp_gas>.
I know brazing is not welding, but it might be an issue. Mind you, it
could hardly make the thing worse at the moment.

 

What guage wire do you normally use ?.
If your gun is set up for 1mm you should fit the correct liner and
nozzle for 0.8mm.

 

I've used it on 1mm microbore tubing and 1mm sheet, using the normal
"Coogar" mix gas, an' all. Making custom rack for a pushbike.

worked OK.

 

Sounds like I just need to practice, er, lots.

Thanks, I think!

 

Liner is PTFE, intended for .6 or .8mm, and I have both .6 and .8 tips.

I usually use .6, for small mild steel jobs. It works well even on
rebar, as long as I give it enough welly, and the weld penetration is
adequate for the light duty stuff I need to do. I know it's no good for
big fabrication work.

The welder's probably good for around 130A (officially 150), and has a
good wire feed mech. that doesn't slip, although the controller circuit
is badly designed (fed off the welding Xfmer, so the voltage bounces
around dreadfully).

The last s/s project I tried with it rusted at the weld (same wire). I
may have had the Argon down too low tho, and I didn't pre-heat it. Will
try more gas, preheat and faster wire this time (and practice on scrap
first).

Cheers,

S.

 

That's a very kind thought. I'll see what I can find gas-wise & go from
there. My plumbing soldering's fine, so brazing/silver soldering can't
be all that hard. Meanwhile, that scrap SS is in my sights...

 

The message <>

Brazing and silver-soldering (white metal brazing, basically) is a
doddle with gas.

 

need to get the feed/power ratio right, as ever - more important the thinner
the material.

 

It needs to be welded with a TIG setup by an experienced welder or you'll
end up with a mess. Take it from a Yank Master Welder and lifelong Triumph
rider.

BTW- Merry Xmas from across the pond.

Brian

 

Depends on the quality of weld expected. I've repaired my Guzzi's SS
collector box with a MIG welder using 0.8mm wire. The weld went black
but cleaned up icely with a wire brush. Still hasn't failed for some
6-10K miles.

<fx: touches wood [fnarr]>

 

That's what I'm going to do. The collector box split a while back on the
same exhaust set, and was MIG or TIG welded beautifully by an expert
(didn't see it done, but think it was TIG). I've done SS with 0.8mm in
the past with mixed results (went a bit rusty), but the plan this time
is to heat it well with MAPP gas first, then turn the argon well up - I
don't think I had enough gas flow previously.

Santa brought me an auto-darkening shield for Christmas, which I've been
playing with already - wonderful bit of kit, should've got one years
ago. I've also got some thin scrap SS to practice on this time, which I
didn't have before.

And anyway, it wouldn't be an SOB if I didn't fettle it myself...

 

Yeah, I bought one of those shortly after I bought my new welder (back
in the days when I had money) and they make life *so* much easier.

Indeed.