Hilarious driving home of a lesson about electrodes and the polarity
Yesterday, all way from 0730 to morning break at 10am, had the welding
machine on DCEN for 7016 rods. Did metres (yards) of weld.
I did have a properly formed weld-pool at all times, it must be said.
Swapping to correct (DCEP) polarity, the welds were twice as fast and
twice as good.
The mea culpa bit.
My colleague helped me set up my next rubbing strake - capped with 5mm
flat. Tacked it in place.
He knew it is unnecessary to remove paint and generally clean, so
helped me by tacking it down over paint.
Well, the weld-pool was boiling like a witch's cauldron with pyrolised
hydrocarbon residue of incinerated paint blowing through it.
Plus I sometimes could see white smoke travelling up inside my visor
from where it had jetted-out in just the right direction. Not happy
on at least two accounts.
The pleasant ambience of the day was detracted from by much
profanities, it could be confessed.
I asked my colleague how he got his neat welds (there were, fairly).
Well, it was like it being demonstrated that someone with Parkinson's
Disease can be a good welder. He was whipping and dodging the rod
around like mad - something like out to 40mm of outriding - while
overall puddling-up a reasonable weld-pool inspite of all the
blowing-out smoke and everything. Then lifted his visor and asked
"Well, what was so difficult about that?".
Myself being mindful that many would say that for any Basic (Calcium
Carbonate based) flux - 7015/7016/7018 - you are supposed to keep a
very short arc and move very slowly were you to as much as weave at
Obviously, I'd never thought to practice 7016 while imitating having
the "Saint Vitus' dance" ailment - so felt short of prior experience
in his technique.
Surveying the double figures of metres of welding still to do, I cut
the tacks, chopped off the rubbing strake where weld so far finished,
with a slitting disk in an angle-grinder, and fetched the
diesel-driven air compressor and the needle-gun.
It took 2 minutes a metres to clean down clean bare metal along the
top of the strake. Where paint had been, it came out silver. Nothing
re. time, in the overall task.
I tacked back on, then got the first couple of inches of the strake
welded back on. Then grooved-out the joint and welded the strake back
together. Well, in the 9/10ths darkness of the winter night already
closed-in at end of the working day, there I was, lying on the hull,
looking mesmerised at these three flames like a cross between a
birthday-cake candle and a gas lighter set excessively high,
evenly-spaced across my weld, giving a clear steady beautiful light.
I didn't reach for my mobile device to take a picture, as it would be
all over too soon and I would miss the beauty of the three flame-jets
firing out of the three pores tunneled through the 5mm depth of my
weld. Except I would have had time - they went on and on and on as I
revelled in the beauty of the light - yellow enough to be warm but
white enough to light my work area. So that hydrocarbon residue was
all coming from the half of the weld - the side under the strake
already there which had been laid over paint.
So when the next day at 0730 I changed my mind from starting doing
some minor work with small 6013's on DCEN and went straight for the
main strakes with 7016's and forgot to change the polarity, and didn't
register the rasping arc and other obvious protests about wrong
polarity - I offer in explanation my previous day messing-up my recent
Back on DCEP, yes? The welds flowed-in fast and smooth, with a wide
"sweet-spot" of good welding conditions.
PS - 'nother advantage of using the needle (de)scaler, BTW...
My colleague's quick sweep with an angle-grinder filled the air with
paint dust and rust, despite leaving most of both in place. Not happy
about the dust as I was there welding the previous strake.
Needle-gun - you eject spalled-off scabs of paint and rust - which
scatter around and there is zero air-borne. Vastly preferable.
3 years ago