Chris, another great tip. Thanks. Steve, I hope you put a welding section on
the United Site. This is good and very useful stuff.
Larry
Chris Hill wrote:
> Tom,
> A little add-on since, as noted, you're never going to get away from the
> occasional blowthrough.
>
> Tip #1 -- Blowing a hole is like falling skiing. The longer you wait
> to accept the obvious, the worse the consequences. When you see the sag
> start, the color change, even the sound change....stop! You'll still likely
> have a hole by the time you get your finger off the trigger, but it'll be alot
> more manageable.
>
> Tip #2 -- Fixing a manageable hole is the easiest thing in MIG
> welding, if you set it up right. Try this, it's very fast because it requires
> virtually no waiting. Tim noted that pulling away from the surface slightly
> will create a little ball. This can be very useful, though you want the ball
> on the surface rather than on the wire end. Turn your welder down one (or two
> if necessary) heat settings. Put the gun down on the surface, 30-45^ to
> vertical with enough wire out that it touches the surface about a 16th to a
> very short 3/32nd from the edge (more if very thin). Tap the trigger (about
> the duration of "1" in counting a second as "one-thousand", or a hair less).
> You now should have a little glob next to the edge. Do this all the way
> around the hole (NOT in sequence -- dot around) until there are no gaps. By
> the time you're done, it will look like a mess, ugly and there may be a fair
> amount of that brown oxidation byproduct around. Ignore it if you want since
> it's about to get consumed and the penetration of the little globs is slight
> at best, don't resist wire brushes too well. Go back to normal heat. Start a
> bead with the gun straight down at some point in the ring you've made. Follow
> the ring around at a hand speed that just melts the ring onto (not into) the
> surface metal. When you close the ring, immediately increase your hand speed
> and spiral around in a circle closing inwards. Stop as SOON as you see the
> middle of the hole disappear.
> This is functionally the same as Tim's method, heat is absorbed by the
> melting blobs, which then provide support on cooling as you move further, but
> it's very fast. I don't even bother putting the visor down for the blobs
> part, just look away each time since the gun is braced on the metal, and I
> usually stop briefly after completing the blob ring to let things cool, just
> to be antiwarp safe. But after a little practice (very little, this really is
> a fast learning curve), if you don't bother to wait, you can do a hole start
> to finish in 20-30 sec. !! And it will look good and be clean solid and
> almost flat metal.
>
>
> Chris Hill
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