I'm in the middle of teaching myself to MIG weld using a Ready Welder and a
TA185TSW. I'm welding hot rolled steel with the mill scale removed.
I'm getting a lot of brown soot around the weld bead. I could find almost
nothing in the archives. Is this normal? Indicative of something I'm doing
wrong? Incorrect settings or problems?
Ive read a few of your posts lately, and... I may be wrong, but it seems to
me that you could benefit a *lot* from an hour sepnt with someone who really
knows their welding. Im a relative newcomer to the industry with 5 years
experience (in australia) as a welder/boilermaker but have had a pretty wide
experience during that time with work in areas as wide as mining, pressure
vessels, marine aluminum, prototyping and jig making. Im certified to weld
pressure vessels as well as structural steel in downhand and vertical up in
If i were in your position, what i would do is seek out someone who is clued
up about welding and get them to show you a few things. you'll learn a lot
more in 10 minutes with someone who's in the know than you will in weeks of
tinkering and reading about it on the web. talking about welding is like
dancing about singing. Trade qualifications mean surprisingly little in
this area - ive met so many tradesmen in my time who have 20+ years in the
industry but still dont actually know how to set a welder. they often rely
on pencil marks on the welder itself for the settings, and they get crazy
mad if you adjust it!
There are no hard and fast fules about welding.... every material is
different, as is every weldment. a butt joint will require a different
setting from a mitre. as a general rule though, an outside mitre requires
about 30% less current than a butt joint while an inside mitre requires
about 30% more. vertical up requires a lot less heat than welding on the
flat or vertical down. All this talk is really pretty useless though except
in terms of a general understanding of more or less is required.
starting with gas coverage, about 15lpm is a good start. keep your nozzle
clean of spatter, aim your gun towards the direction of travel, and make
sure that you dont have any wind/fans blowing your shielding away.
shielding in itself is an art, but the basic points mean consistency.... a
consistent gun angle, avoiding jerky movements of the gun.
removing the mill scale is nice, but most people rarely bother unless the
weld is to be certified. Im not familiar with your machine, but im assuming
that it has a few settings on the front for voltage, maybe A through E? If
so, your going to want to go with 'E' for anything 1/4" and over. 185 amps
really isnt much to work with, but with chamfering you could realistically
weld 1/2" material in a few passes.
so, start with your highest voltage setting. now, get close to the feeder.
hold the gun in which ever hand you normally use, and put the other hand on
the wire feed control. If your feeder has a '4 touch' setting or 'latch'
setting whereby once you press the trigger it keeps welding until you press
the trigger a second time, then use it. This is one of the secrets to
accurate consitent welding in all positions. start welding, and adjust the
wire while you are moving. turn it up to the point that the gun is kicking
back in your hand, making a machine gun sound..... this is too much wire.
now turn it down until it feels and sounds 'smooth', this is the earliest
point where it feels and sounds good to you. This setting will be a
slightly 'cold' or 'proud' bead. weld for a while, stop and have a look at
now keep welding, and adjust it down further... keep going until it seems
to 'stall' and drip off the end of the wire... this is too low. but do a
weld anyway... look at the finished bead. notice the browning? see how
the spatter is really hard to remove? now weld again and turn it up, turn
it down... you dont want that dripping, but you dont want it kicking back.
while everything is a personal preference, and gun technique changes many
things, you will probably want a setting just above the 'drip' setting,
rather than just below the 'kick' setting.
as a general rule... more voltage = a flatter wider bead with more
penetration, while more wire *reduces* the amount of heat. in general, set
voltage for the penetration you want, and then adjust wire to suit. too
cold? turn voltage up then adjust wire again. too hot? turn voltage down
and adjust wire to suit. browning would usually indicate too high a
voltage, or too little wire, or not enough shielding gas. the overall
verdict is too much heat. when you have excessive spatter, or the spatter
is really hard to scrape off but you have a good looking bead, its a sign
that you could probably tweak your wire a little bit.
every welder (machine) is a little bit different, even the same model.
every weldor (person) is also different. gun technique does make a huge
difference in the way the heat is applied, with gun angle, stickout and
weave being the main components. many weldors are really bad at setting
their welder, but very advanced at using gun techniques to increase or
reduce heat. My personal technique is very adaptable, but a signature of my
style is using a short forward step with a longer backstep for tha roll of
dimes effect. at higher currents (300amps+) i tend to avoid direct arc at
the edge of the bead, instead 'washing' the pool to the edge of the bead on
the backstep to avoid undercut.
I haven't seen any soot , but do from time to time have small glassy brown
bits of slag . Always on top of the bead , and it comes off fairly easily .
I learned here that this is probably contaminants from my base metal , and
if I want it to go away I need to brush/grind/file my metal cleaner .
If y'all will wxcuse me , I'm gonna sit back and play sponge some more ...
I get that too with this process. The little bit of searching I did
indicated - I thought - that this was not a problem as long as it was
scrubbed away before laying another bead on top of it. I'm wondering now if
that's correct. Of course I get less of it since I cleaned the mill scale
off the pieces on which I'm practicing.
The glassy deposits are indeed slag. It comes from excess silicon and
manganese in the steel welding electrode consuming the oxygen in the weld
puddle. One would think the shielding gas is perfect, but it's not.
Atmosphere does impinge somewhat on the welding arc and surface of the weld
puddle, but the composition of the wire compensates for that.
And yes, it needs to be cleaned from the surface before welding subsequent
beads or layers.