Hey, Ernie, I got the CST 280 about 10 days ago but then had to spend
4 days out of town so I have not had much time to play with it.  I am
finishing up a smoker and have been using it on that.  The first day I
played with the welding machine I just tried my various rods on scrap;
6013, 6011, 6010, 7014, 7018.  Everything seemed fine.  However I have
a problem now and I wanted to run it past you and the group.

On the "real" welding (on the smoker) I've been using 6010 5P+ 1/8"
rods (Lincoln Electric) and 7018 1/8" rods (Forney).  On both rods I'm
getting surface pitting and voids in my weld beads.  They are somewhat
similar to what my MIG welder does when it's run with too little or no
shield gas.  The 7018 rods are brand new out of a sealed package but
of unknown age (purchased from a business that was closing).  The 6010
5P+ are the same rods I've used for a couple of years from the same
package.  I have run root passes with the 6010 5P+ which are flat butt
joints, overhead fillets, and downhill fillets.  I have run caps over
both the 6010 5P+ and my wire welding with the 7018.  The worst I've
seen was yesterday while welding up a stick of 2" x 2" x 1/4" angle
vertically onto a piece of 1/4 inch steel.  I was welding the inside
curve of the angle and it should have been easy but at the end of the
weld (where the angle and the base piece terminated) I got a spongy-
looking mess, very reminiscent of a poor MIG weld.  Sometimes I even
get a little "egg" growing on top of the welds at the end, similar to
when I run my MIG welder with too little shield gas.  And finally, I
have noticed with the 6010 5P+ I am having the arc blow out to the
side and not remain constant from the tip of the stick.

All of this has been done on 1/4 inch thick mild steel.  I have been
running the 6010 5P+ at about 90 amps in the XX10 Stiff setting, and
the 7018's in the XX18 Soft setting.  I could hook up my old Hobart
welder for comparison but I used the cables from it on the new
Miller.  But I never remember having problems like this with my old
Hobart.  Could it be the CST 280?  I wouldn't think so, it's just a
power supply but what do I know?

Thanks for your time and any advice.

--HC

90 amps is a bit low for 1/8" 6010, but doable I suppose.

Lincoln 5P+ is the best 6010 I have used.
Have you checked your rods for rust?
Depending on how old and how they are stored, the wire could have
rusted inside the flux.
Just bend one into a U and look at the wire where the flux peels off.

6010 should never be baked as it needs moisture to work right.

Forney 7018 is crap, sorry, but it is.
Even Murex is better and that is crap too.
If you want good 7018 buy Lincoln Excalibur.
Lovely stuff, just keep it dry dry dry.

I have seen similar things to what you describe, but only when dealing
with painted objects or when welding against wood.
When you stop welding the still hot puddle reacts to contaminants on or
near the metal and gets porosity.

The power supply would have no effect on weld contamination.- Hide quoted
text -

- Show quoted text -


Thank you, Ernie, for your reply. Your comment about the 6010 being
"doable" at 90 amps indicates it might be too low. My reading online
had (and I double checked, now) indicated that 75 to 125 amps was the
range for that rod. Should I be running that higher in the range of
75 to 125 amps?

I have not checked the rods for rust. I have used the same rods on
both the Hobart (old) welding machine and the Miller CST 280 (new)
welding machine. I will check the rods for rust per your
instructions. Also, I have some extra quick connects (Tweco-style, I
think, but, regardless, I can make a doable setup) and an extra
electrode holder and ground clamp which I will hook up this Friday if
my schedule will allow it and I am going to do some head-to-head
between the CST 280 and the old Hobart; I will feel better seeing
their results side by side. I won't feel better until I see that the
new machine welds as well or better than the old one. Yes, I am
obsessive. :(

I have been cooking the 6010's in my kitchen oven some (not this
current batch) because they were given to me and came in an opened
package and I feared they might have taken on moisture. Based on your
information here I will not do that anymore.

This is my first batch of Forney 7018's. Previously I was using
Hobart 7018's. I only, as I posted, got the Forney stuff because it
was cheap from a place closing the business. I will see if my local
shop has some Lincoln 7018's. I have rod storage tubes which should
help keep them dry.

What I'm taking from what you are saying is that ONLY weld
contamination would cause the porosity, voids, or similar failures in
my weldments. Therefore, as you say, the power supply would be a non-
issue.

I know I'm being uptight about this and panicky, but I'm sitting here
with about 2k paid out and uncertain of the cause of my problems and
nervous. It's just me. Thank you for your time, help, and patience.

--HC