David Billington wrote:


You can weld Al with DC but use the reverse polarity to what you would
use for steel. I have never tried it. It does result in much more heat
at the torch so you would need to make sure the torch was up to it. I
think this would be like running AC TIG with the cleaning setting maxed
out.


Tried it using both polarities and scrubbing like no tomorrow

DCEN
It hold an arc but staunchly refuses to flow liberal application of
filler can bind them but there is no strength (Logical reason being the
aluminum is encased in aluminum oxide which is forming a solid shell

DCEP
Black coating forms on the base metal arc wont strike

that COULD be me under scrubbing it (with the decicated AL only SS brush
mentioend in other posts which i already DO have)

But if so then i'm buying a few ss brushes for the dremel and using it
to prep my welds if i need to DC weld on AL again



your Descriptions though dont really sound any different from What it
does on TIG when i had access to an AC/DC machine.

Perhaps i should ask it this way how close is it to tig without the
pedal control? I know i needed a Lot of practice to do Al in tig when
i was learning but i saw the same conditions I think.


Quite similar except you can control the heat with the torch distance
and attitude, also you can add more rod to the pool briefly to cool it
and help bring it under control. You also don't have to worry about
dipping the tungsten or hitting it with the rod. I would say that
welding Al is only slightly trickier than welding steel. I learned to
weld steel with OA and had a few years practice then tried Al and was
laying runs under control on Al after about 5 minutes practice. Due to
the similar skill between TIG and OA if you are having trouble with TIG
then it going to require practice with either process.


I'm fine on Steel and stainless TIG AL tig i was in the process of
learning then bought a DC welder and stopped

I dont thing i'm ready for an AWS test yet on steel or stainless (I
grind way too much tungsten for now)

but i can produce decent welds when i'm patient (they might be good
welds but i'm my stiffest critic and i dont think so






David Billington wrote:

Sounds about what I would have said. I found there is a subtle change
in the surface of the aluminium before it drops on the floor, I
learned to recognise this and all went fine. I have never used
anything other than standard OA welding googles for Al and never had
an issue with being able to see what I was doing clearly. People
mention using special lenses to cut the flare from the glowing flux
but I have never experienced this. I have never welded Al with OA
extensively and these days would typically use TIG unless I had a
benefit from using OA, typically it leaves a more ductile weld which
may be beneficial if you are doing panel work.

Buy_Sell wrote:

I gas weld aluminum. I use my Henrob torch for this but any gas torch
will do. The trick is to keep your gas pressures set low. If you need
more heat then change to a larger tip but keep the oxy and acetylene
pressures no higher than 4 psi. The other thing that you will need is
some flux for your aluminum rods and a good set of special goggles for
viewing the weld properly. A few years back everyone was using these
cobalt blue goggles but they weren't that good for your eyes. I use
goggles that have a gold reflective surface on them. I picked them up
at the welding shop and they work really good. Welding aluminum is a
bit tricky because the color doesn't change when the metal heats up
like steel does. Aluminum is a bit like plastic, one minute its there
and then all of a sudden the floor drops out and you have a big hole.
The trick is to look for when a skin appears to form on the surface and
then push your filler rod in and a way you go. Without the special
goggles, you won't be able to see the skin effect. Practice on lots of
scrap stuff first before getting into some more serious work. You'll
get the hang of it in no time.

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Brent Philion Jan 22, 12:08 am

With the lack of an AC tig machine and an AC inverter appearing to not
be in the cards in the near future i"m looking at using Oxy/Acetylene
to
do the al Welding due to the availability of an OA rig. Mainly i used
it
for cuttingbut thats not to say its impractical for welding. If i
remember right OA has been used for Al welding for a long time
specifically in the aviation industry.

Compared to TIG how hard is OA welding of aluminum and are there any
special types of requirements for doing it? The only OA welding i would
be doing would be on Al and the rest of the time it would be used for
heat/cutting

I already have an OA torch (Cheap Harris style kit) but stumbled across
a real Victor 100 Handle Might i be better off getting a fresh welding
tip for the victor 100? than the giant beast of this harris one?

I will likely never weld larger than 1/4" with most work being smaller
than that (1/8" to 1/16")