On Wed, 29 Aug 2007 02:42:33 -0700, Andrew VK3BFA
wrote:

Hey good people - welding stuff first, as its driving me nuts........

My welding is getting reasonable, the welds don't break when I hit
them with a 5lb hammer. Slag (usually) chips off in one piece with
minimal effort. I reckon thats pretty acceptable - know bugger all
about stress engineering, so I cross brace everything I am going to
stand on 20ft up in the air so if 1 or 2 break, I don't go whoops....

Good man! When in doubt, over-engineer it. And if you;re going to
be up in the air, rig a safety rope and a harness. Better to let the
Fire Department come get you down...

But think through the point failure mode and the load shifts that
will occur during the failure as you design anything that moves,
slides, swings or holds up people. If the weld on Mounting Tab A
breaks, you don't want the heavy item to move very far or gain much
speed before Tab B catches it, or you shock load Tab B and break it
off, then the load shifts to Tab C that fails... And it all unzips.

So kept em warm (on top of the PC monitor) for about a week now. Still
weld crap. Slightly better (but still crappy) results if I crank up the
current to 80 amps, the previous ones ran fine on 65 amps. So, what
gives - tonight, I got really ****ed off and rummaged through the
junkbox and found 2 CIG 'Satincraft" rods that had been sitting in a
damp garden shed for years, they welded real good. Lashed out a while
ago and bought a little DC inverter welder and a LCD helmet -
wonderful inventions, both of them. Highly recommended.

The top of your PC Monitor is NOT a rod oven - not nearly hot
enough, and not controlled humidity. And this only works for certain
flux coatings (cellulosic IIRC) where moisture matters, some rod
fluxes don't give a darn if they're dry, wet, or used underwater.

You can dry rods out in a repurposed electric kitchen oven, go find
someone doing a remodel and snag their old oven when they put it out
in the rubbish. Or build your own rod oven out of locally available
"field expedient" materials - an electric oven element and the ceramic
stand-off mounts, adjustable thermostat, sealed steel inner enclosure
long enough to hold your rod, fiberglass insulation, something for an
outer enclosure.

Any explanations on whats going on and how I fix it, or do I just bin
them and buy some more Chinese ones.....saw some at the markets on
Sunday, $4.50 for 2.5Kg - sounds too cheap to be anything but junk,
but I don't know. Tempted to buy some jsut to stuff around....

Buy known type and quality rod, it's not that much more. And you
don't have to wonder if the problem is you or the rod.

Another welding question - I am OK at horizontal welding, but this
limits what I can do - some things are just not able to be maneuvered
around to get this alignment. Vertical welding is a problem - is there
a "recommended" way, ie bottom of weld UP or from top DOWN. Molten rod
tends to flow and bugger up what you haven't welded....

I don't stick weld that much yet, almost all MIG with CO2. But it
can almost always be solved through a combination of technique, rod
selection and work positioning. Some rods burn great on dirty metal
or in odd positions, some don't. And there is usually a way to
reposition the work, or the worker, to get a proper angle on the
problem.

And another....welding galvanized pipe/tube. If I grind off the gal,
welds like ordinary steel (yes, I know thats blatantly obvious) - if I
leave the gal coating on, get a yellowish fumes, and a white, cotton
like deposition on the surfaces,- is this a BAD THING or not?.....

Zinc fumes from galvanizing are very bad for you if you get a lung
full of them - Zinc Fume Fever. Grind off as much galvanizing as
possible to keep it out of the puddle, you can send the finished
weldment out to be galvanized again when you are done.

Always have the wind at your back when welding even cleaned-off
galvanized items, or a fan at your back, or a remote air feed
respirator system if you are working in a confined space.

And and and.........finally found out what a "Dead Blow" hammer is
USED for - people here had kindly explained what it was, but last week
in Milling class was shown how to use it - used for setting job in
vice as it doesn't bounce and so the job doesn't recoil either....

Moves really heavy things without a lot of effort expended or
wasted. ;-) Where you used to have to whack with all your might with
a rubber mallet (and mind the recoil!!) to get motion, you only need a
few taps with a deadblow.

and and and.....can anyone out there can point me to plans (free) for
a SIMPLE flat bar bender - got some "honey do" projects, - (I thin
kit was Don Foreman who coined that phrase - very useful and
descriptive for the household projects) the ones I have seen have
been too complicated for a novice like me, they are adjustable for
different sizes of bar, either by different size dies or cam
adjustments - I am happy to make it "one size only" for the few things
I want to make...

Don't they have a "Harbor Freight" clone over there selling Chinese
made tools? Sometimes it's a Lot easier, less expensive and faster to
buy it pre-made than try to reinvent it - spend your time making the
project, not the complex one-off tooling to make the project. They
churn those benders out by the thousands, for pocket change.

-- Bruce --