hey Jody here today we're TIG welding on some 18 gauge cold-rolled steel lap
joints let's do it so we'll be going over some tips and
techniques for flash tacking the different amp urges and settings for
tacking as opposed to welding using some big chunks of aluminum for a weight as
well as some heatsink some tips and techniques for the weld out and of
course some good instructive arc shots so the first one we're going to do is
tack with a number five regular ceramic cup with only about ten cfh of argon but
not only saves gas but it also helps get a nice crisp arc start if you've got a
big blast of pressure on your arc start a lot of times your arc start will be
erratic and what I'm going for here is really small clean tacks so I'm just
gonna blast it with a really quick burst of 80 amps that's a lot of amps for 18
gauge steel but I'm gonna be on and off the pedal so quickly that all it's going
to do is put a nice clean tack on there that barely nips the corner and when I
go back over that with the weld I should be able to completely consume that where
you can't really tell where the tacks are you could use you could use a
screwdriver to hold it down I'm using a copper spoon I got from Harbor Freight I
have also made you know DIY tools just building up the tip of an old trapping
screwdriver with silicon bronze and then shaping it however I want to for doing
this operation it helps to hold it sometimes right next to where you're
gonna well you can not only put a lot of pressure on it when you can't get a
clamp on something you can put a lot of pressure on it to get rid of the gap and
you don't want any gap in the thin lap weld at all so I've got a tack about
every inch or so there it's time to switch over to a bigger Cup now for the
weld out I'm using a clear eighth cup here I'll show you a little bit more
about that at the end of this video I got a crank my my argon up to 20 cfh
now for the eighth Cup something else that's going to help a lot is using
these big blocks of aluminum not only as a weight to keep it from wobbling
sometimes when you light up on something that electricity goes through it it
starts wobbling and chattering and everything but not only is it a weight
but it's a heat sink and it traps a little bit of argon entry helps it helps
a lot I know I've said this multiple times but I'm going to say it again I
started using clear just to help film so we could all see
the arc and where I'm going and where I've been a lot better but I noticed
they helped me to see where I'm going a lot better as well they just kind of
light things up like a flood light bulb ahead of where I'm going I can use all
the help I can get these days the thinner something is the more
backstep technique that I use and that's what I'm doing today here I'm back
stepping a little bit I'm welding half of this run first and then backing up
and welding to to the start of that previous bead I don't want to go too far
this is kind of rigid because it's a cube but on certain things they'll the
farther you weld the more they'll distort and making nice short runs and
back stepping your welds on sheet metal it helps a lot in avoiding distortion in
fact when I was making this cube in a prior video I used these big aluminum
blocks for the outside corner joints to pull heat out and they worked great and
I'll try to link that up about right here well let's keep going with this
thing up in just a second we're going to talk a little bit about machine settings
and kind of how to determine what amperage you need for a sheet metal lap
joint like this one way to figure it out is try to
figure out the minimum amperage it takes to run a fusion pass without filler
metal and then just add about 5% more amps when you add filler now I'm only
using o45 filler here so I only need just a few more amps as opposed to what
it would take for just doing a fusion weld but here are the basic settings for
the flash tacking as well as the weld out one of the biggest mistakes you can
make on a lap joint on the thin metal like this is too long of an arc that's
probably the biggest one it needs a tight arc so what is a tight
arc well in my opinion it's the diameter of the electrode or less now if you get
too tight you'll start sputtering and you'll be cleaning electrodes all day
long but I'm using a 3/32 diameter electrode here I'm striving for about a
1/16 arc length another thing is torch angle you don't
need that much fortunately torch angle is pretty forgiving especially if you're
holding a good tight arc a lot of times you think you've got about a 10 or a 15
degree torch angle and you've got more like a 25 or 30
like looking at this right here I'm probably at least 25 but it's working
out just fine due to the Thai dark an obvious tip is
to make sure to have a clean sharp electrode I'm saying it anyway because
it's really important if you sputter and get a little fuzz on the tip of your
electrode on a joint like this on pretty thin metal on a lap joint you're just
not going to be able to direct that arc like you want to so keeping a nice sharp
clean tip super important this is about how I prep them for a job like this
let's take a look at the filler rod hand now for this little run I'm choked up
pretty pretty tight on it because it's o45 filler the smaller the filler the
tighter you have to choke up from the tip to where your hand is otherwise
it'll flop around too much and I'm dabbing rod about once every
sixteenth of an inch or so now if this were thick aluminum I'd be probably
stepping out almost an eighth of an inch but it's not it's thin steel I try to
step out too far the edge is liable to curl away so it's good it works for me
to keep the rod dabbed in there fairly often now this is the last run here and
there's really nothing new to show so I'm just gonna speed things up here so
we can see the finished product lap joints are used a lot for repairs like
doubler repairs on grit blast cabinets or even in aviation
so this cup did a great job here's a few other clips of previous videos here's
one I was welding a cube on aluminum using the same 8 clear cup it's a good
all-around cup for both steel and aluminum sometimes it's a real big help
to be able to see through the cup to be able to see exactly where your tungsten
and your wire is but the real benefit for me is it just lights things up and
helps me see better if you think it might help you if you're having a little
trouble seeing where you're going go to the weld monger comm check it out if it
makes sense for you you can read some of the reviews and they're put together
some little packages here some little small convenient kits that have a
ceramic as well as a clear cup for each torch whether you got a 17 18 26 or a 9
20 style there's a kit just for your torch along with some visual aids to
tell kind of torch you have so if this makes
sense for you check it out at well monger calm thanks for watching we'll
see you next time
you