I have a Lincoln SP135T and have been trying to weld some 3/16" angle.
I ground the joints out in a V and still the weld is not penetrating
all the way through. I would guess on average the thickness at the
bottom of the V is about 3/32" although I didn't actually measure it.
When I mentioned this to one of the sales people at the Lincoln store
he told me to use a higher wire feed rate becuase as he put it "more
wire is more amps". I tried that and actually seemed to get the
opposite results. When the feed dial was up close to 7 I would get a
lot of weld but it was very round and appeared to be sitting on top of
the metal. As I slowed the feed down closer to 6 I seemed to get
better penetration but not all the way through. Should I try a slower
wire feed rate or is there something else I can try? I'm using
Argon/CO2 mix for gas and .030 wire. I just bought a small spool of
.035 wire and new tips to go with it. I'm also trying to find a
welding class near me.
I don't plan on doing a lot of metal this thick but its what I had
around and wanted to use it to build my welding table.
Move down to 0.024" wire.
It is the best size for 110 volt MIGs.
They just don't have the power to burn larger wire effectively.
Run your power at the max and adjust the wire speed until you get a
steady sound like somebody ripping heavy fabric.
Weave your bead a little side to side and travel in a backhand
Backhand means you are pinting the gun where you were, not where you
Backhand gets you higher penetration.
Forehand gets you lower penetration.
Neal, charts on Mig welders and salesman's recommendations are a rough
starting point. Every welder is going to run differently and your
line voltage may be higher or lower than someone elses. Another
variable is that every weldor is different too. Goi with what works
best for your machine and remember that if you use it somewhere else
your results may chnage a bit. .030 seems to be a good size for the
135 amp welders; I have heard from several people that this is their
"go to" wire.
If you try to weld forehand with most rods, you get slag inclusions.
The only exception is Vertical up welds.
Same thing applies to Dual-shield and Inner-shield wires.
Anything that leaves a flux layer is normally backhand welded.
Aluminum MIG is always Forehand or you get really nasty looking welds.
Look at Volts relative to amps chart at this link.
as you turn up your wire speed getting more amps the voltage is
only about 16 Volts. Maybe .024 wire will help. But if you look in
your manual it clearly states thickest metal that can be welded with
solid wire and shielding gas with your SP135 is about 1/8". The manual
and the setting chart clearly states that you should be using .035
fluxcore to weld 3/16" steel with that welder. You have tried to push
your welder beyond what Lincoln says is possable. If you want good
welds try following the welder's setting chart. Trust me it works.
The manual and the setting chart clearly states that you should be using .035
fluxcore to weld 3/16" steel with that welder.
The way I read that chart is "single pass" maximum is between .135" and .188"
depending on wire used. Multipass maximum of up to .313" with fluxcore.
I have seen 1" plate V-groove welded with the SP-125 Plus using fluxcore and
both machine and plate came out just fine. This was done just to see if the
machine could do it and not for any other reason. These are generally hobby
welders and not really for a 24/7 environment but well made albeit. Neal, you
should have little trouble welding 3/16 angle with that machine and some
knowledgeable puddle watching. You will NOT get penetration all the way through
like you stated and maybe the problem is that you misunderstand that a weld does
not have to burn all the way through to be good. The welds don't have to
penetrate through like we learned in Oxy-Acetylene school with thin plates. The
puddle just needs to melt into the parent metal at the edges as well as the
First thanks to all for the help. It looks as though I have a couple
of different approches to try.
Duncan: Thanks for the link to the pdf but I don't see where you found
the 1/8" max. In the third paragraph under Advantage Lincoln it says
"Capabilities include welding 24 gauge through 3/16" with MIG and up
to 5/16" with self-shielded flux-cored wire" . In addition the bar
chart on page 2 shows 3/16 (.188) in the single pass range for .035
MIG. Admitedly this is the max and perhaps as a beginner I'm pushing
my limits more than the machine.
I have .024, .030 and .035 MIG wire to try and perhaps I will get some
flux core to try as well. I have been doing forehand thinking that I
would get better penetration so I will definately try backhand (thanks
Guess my gas welding training was showing through hey :-)
Got mine at East Coast Aero Tech in Lexington Mass in 1971. Boy do I
feel old :-)
How is it that a weld can provide full strength if it does not
penetrate the full thickness of the metal?
I realize I'm not building a structure that will see extreme use or
where peoples safety is at stake so for this project I'm sure it isn't
an issue. However I would like to be able to get it right when the
need is there. Of course at this point I don't really know what
"right" is but I'm still learning.
How is it that a weld can provide full strength if it does not
penetrate the full thickness of the metal?
I learned the answer to that one right here on this NG. I'm not real clear on
how to answer it but I suppose it is partly intuitive. I welcome the clearer
thinkers amongst us to join in.
Melting metal and splattering it on top the joint of two pieces of metal is not
welding, but once you have both the work and filler to liquid state they marry.
Spot welds and stud welds are good examples of next to nil penetration yet they
still work and are used widely. If the work truly reaches melting temperature,
penetration is not an issue and happens on it's own (IMO).
I think here is the catch. Electric arc welding takes the work "spot" up to temp
rather quickly. The work metal has the ability to absorb that heat quickly so
the machine must be able to surpass the heat sinking and actually melt the
filler and work "spot". The larger the work piece and electrode, the more energy
it takes to get them both melted at the same time. The puddle will tell you when
the parent metal is melting. You should see something like a glittering spot of
mercury. The color will vary depending on your lens. If the electrode has flux
it may hide the molten metal a bit but you should still be able to see it at the
front part of your run. It will be the brightest part. One of the best tips I've
learned here is to pay close attention to the "puddle". You will not have to do
destruction testing once you get used to how good puddles look. You will know
before you raise your hood and the metal cools if the weld will hold or not.
With your 3/16 angle, I would just leave a 1/16-1/8 gap and weld it up with .023
solid wire and try for a single pass. No veeing or other pretty stuff other than
grinding the rust off and maybe doing the other side for practice. If you are
new to MIG, give yourself at least a two pound roll to play with on any metal
you can scrounge in the trash etc. Keep a few notes especially about the stuff
you do right and how you think you did it.
So to sum it up, it all depends on you and your machine being able to make a
good liquid puddle on the size piece you plan to weld. I'm not talking the whole
joint, but just the spot where the electrode is working at the moment. Factors
to juggle are travel speed & eccentric motion, electrode angle & stickout,
machine settings, indoors or out, and maybe more. Smaller MIG wire generally
makes a smaller puddle so less work for the machine at any given moment in time.
Of course you will need to come back with multiple beads to fill larger areas.
Thanks for the chance to ramble....
My buddy and I went through exactly that same situation. We both
bought our welders around the same time. He bought a Miller 130 and I
the miller 170. I tried welding 1/4 inch plate with .023 and although
the welds looked good they had little penetration. The higher I turned
the wire speed the worst things got. It seemed to me that the more
amps the faster the wire would burn and of course thinner wire burns
faster than thicker wire. So raising the amps (in this situation) is
just the opposite of how it should be (IMO). The chart said 60 wire
speed with .030 wire and 50 wire speed with .035 wire for 1/4" . Don't
understand that reasoning. Anyway I went to .035 wire and set the
speed down to 40 and all is well. Passed that info. on to my friend
and it worked on his welder too. Also try holding the gun 90 degrees
to your workpiece and a little less shielding gas. That helped a
MIG welding current is a function of wire speed *and* wire gauge.
Heavier gauge wire produces more current (lower resistance), so
the wire speed doesn't have to be so high to get the same current.
I'm sure your settings will not be the same as mine. The point I was
trying to make was, the charts are merely a starting point they can't
foresee every situation. As you've already stated the key is
'experiment' don't be afraid to try different things.
With wier feeders you weld with your voltage setting . With too high of
a wire speed you will have a high amp reading with too low of wire speed
you will have a low amp reading . When you are stick welding you set the
amps , and the gage will read that many amps . Now stick the rod to the
metal and watch your amp gage it pegs the needle . You need a certain
amount of voltage while using a constant current wire feeder to make a
certain size weld on a part wit a certin mass . Too little of wire speed
and you get burn back . so you increase your wire speed witch increases
the volume of metal and starts to weld . turn up the wire speed until
the wire just touches the puddle ,You are where you want to be . Notice
your amp draw . Now increase you wire speed more ,test the strength of
the weld probably weaker now although you are welding with more amps .
Go ahead use more wire speed now you are starting to chill the puddle
before the impurities and or additives float out , you are getting
weaker . Your amp draw is getting higher . Hear is a great test for wire
speed verse voltage . Get your self a handful of 1/2" nuts ,clean and
not coated and a piece of at least 1/4" plate the thicker the better.
Using .035 wire start at 20 volts and stay their . Only adjust the wire
speed . Start at too slow of a wire speed ( wire starts to burn back ) .
Fill up one nut at a time each time raising the wire speed . Get a torc
wrench and start to brake off the nuts . Make sure that the plate
doesn't get hot , that will change the results . 220 wire speed will
probably be the best setting for 20 volts . Try it with the mill slag
left on at first . If you have enough nuts try with a clean plate , you
will have a greater variety of wire feed settings that will be strong .
Now try this wit 24 volts and say 300 wire speed . If you have enough
nuts you will find that you have an even wider variety of wire speed
settings . and you may find that these will be stronger than the 20 volt
ones . For those 120 volt machines you might not even pull off a piece
of the base metal unless you clean off all the mill slag . You will find
that if you very roughly grind the plate it will weld better . I was
using C-25 gas .
Over the years I spent a lot of time trying to find the best weave, only
now that I have a constant shake do I feel content !