Stick welder transformer questions

Hi,
I have an old Abel 130 amp welder that grunts and groans when I set it to 100 amps or more. The hum starts to sound distressed a bit like the
unpleasant edge to a sound when a speaker is overloaded. It does work however so maybe this is okay.
The transformer has a sliding core for amps adjustment which I guess is common practice. What does seem odd is that this laminated core has bulged in the middle so the laminations are separated rather than being close together. Does anyone know if this is right or wrong ? If it is wrong then I might be able to dismantle the core and rebuild it.
Also, there is no sign of any thermal protection device. Does this mean the windings will melt if I push it too hard or do transformers degrade at high temperatures and make the device self-limiting ?
Thanks,
--
Steven

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The older sliding core units tend to get sloppy in their old age, they will really vibrate at the high range. I have an old Airco unit where the slides are plastic, run against the laminations, wear from the vibration. Check yours to see if there are any tighteners, gibs, etc to snug up the shunt. You might have to insert a thin strip of plastic to reduce the clearance.
Most of these old units had no thermal protection, got by with an abundance of copper. If you run it hot, it will smoke a bit, time to take a coffee break. If you are watching carefully, the arc will get a bit mushy as the resistance of the windings goes up.
Steven Saunderson wrote:

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Thanks for the info; I will have another look at the core.

I think I saw this mushy arc effect recently especially on test beads. The bead would start well but after perhaps two inches the arc was much harder to keep alive. I've never worried about the duty cycle because I spend so much time removing my helmet and chipping slag but it looks like I am overworking the welder.
--
Steven

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The mushy feel can come from either hot rod or hot welder. What size rod? What amp setting? Did the effect go away with a cold rod? (the welder won't cool much in the time it takes to insert a new rod.
If the welder is 120 volts, I'd expect the low duty cycle. If it is 240, I doubt if you are hitting the duty cycle that quickly.
How much does the unit weigh? Heavy implies lots of iron and copper.
Steven Saunderson wrote:

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Hi Roy,
I checked the sliding core today and it looks like the laminations are bent so the core is a tight fit in the slides. The slides are aluminium with plastic backing. I cleaned the feedscrew and slides and checked all connections. When welding today (3.2mm rod, 120 amps) everything was the same as before so I presume all is okay.

I was laying 8" long test beads (1 rod per bead). The rods are 2.5mm and the welder was set to 90 - 100 amps. Most beads started okay but the arc became fragile fairly quickly. I was trying beads with 3.2mm rods before (120 -130 amps) and was having trouble. It looked like the flux wasn't melting and I was almost dragging the rod along the metal just to keep the arc alive. All rods are 6013 and I was trying a new brand. The case of the welder was warm but certainly not hot.

The welder is 240 volts with a 25% duty cycle at 125 amps and 100% at 55 amps. I estimate it weighs 30 - 40kg.
I am beginning to suspect the new rods I bought recently. After the problem session I bought a different brand of rods which seemed better. But the welder had had an hour to cool down. As I am inexperienced, blaming rods is a cheap tactic so I've just (mid-post) done another test. I was laying beads with the suspect 3.2mm rods at 120 amps for about five minutes and only stopping to change rods and chip slag so the duty cycle was about 75%. The first bead was okay but after that I had to keep the rod end real close to the metal to keep the arc going. Immediately after I used these five rods I tried an expensive rod (same specs) and it worked well with a 3 - 4mm arc. It looks like I am a dumb newbie addicted to expensive comsumer rods.
The welder case was only moderately warm after this. It looks like it is an oldie but a goodie.
--
Steven

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2.5mm s 3/32" on this side of the pond. 90 to 100 amps on that rod is likely to get it fairly hot, you will get the mushy arc that you are seeing. The amp reading is really only a guide, each welder seems to have it's own personality. Try dialing it down to the 70-80 amps range for the 2.5mm
The welder itself sounds about right for a decent home welder rated at 130 amps max. The weight alone says it has a lot of iron and copper. The buzz is normal on a shunt welder, maybe someone could watch the shunt while you weld to see if it visible moves. I'd guess you could push the duty cycle a bit, run 1/8" (3.2mm) rods at 110 amps pretty much as fast as you can weld and chip slag.
Good 6013 rod run properly will have very fragile slag. On a good day, it will actually lift off the weld about 6" behind the arc. On a bad day, you will have inclusions that bond it on like glue. 3-4 mm is too much arc for 6013, try keeping it to 2-3mm. Push it in tight, it will crackle, pull it out and it will flare out. Somewhere in the middle with a bias toward a short arc is where you want to be.
One other thing to check: after running half a dozen rods, feel around your cables to see if you have a high resistance connection somewhere. Be careful, the bad connections can get really hot. You should also take the cover off the welder, clean out the dust and cobwebs, check to see if any of the internal connections look hot or burned. If it has a fan, be sure to oil the bearings.
Sounds like you are having fun. Get a 5 pound (2kg) box/can/package of decent rod at a welding supply store, start running 4" (100mm) beads on some scrap stock. Use about half a rod on each bead, chip the slag to see your results. Repeat for the whole box. This is all about eye/hand coordination, it takes practice.
Cheers.
Steven Saunderson wrote:

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I had to explain to a welding supply "Zodians are good rods. There's no polite way to put this - I need rods which are completely 'crap'".
This is because the point was to practice for Trade tests where they hand you "white-packet Rutiles" - unbranded 6013's. These usually lack fusing (penetrating) power, throw slag inclusions very readily and have poor slag control for positional welding.
"Machine Mart" (a UK national chain selling mainly their own "Clarke" brand workshop machinery and supplies) sell electrodes which are known in the Trade for being everything you need a "white packet Rutile" to be to stay in practice using them ;-)
But yes - it would be discouraging to use lowest-end rods at the outset.
The AWS classification "6013" divides in European specs to be "R" (Rutile only) and "RC" (Rutile-Cellulose) with a few % of cellulose to give the rod some bite. Some good rutile rods here are "RC" so that they will bite into the metal.
The self-peeling slag thing. This is very sensitive to current and arc-length. Getting self-peeling slag shows you are on the conditions. Current not too high and arc length not too long. Self-peeling slag comes with getting a smooth weld, which is what you are wanting...
I've sent two pix to http://www.metalworking.com/dropbox / with name starting "slagselfpeel"
and put the same pix for now (26 February 2008) at http://www.weldsmith.co.uk/dropbox/sejw /
Richard S
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wrote:

I agree wholeheartedly. When I mentioned I was interested in stick welding recently an experienced friend recommended some "consumer" rods and also the current and angles to use. I had big problems at first (who doesn't ?) and tried some different rods. But after two weeks I realised the "consumer" rods (CIG Satincraft 13) give a much more tolerant arc.
I now have a range of rods (mainly 6013, some 6012). Most are cheap. Some are okay and some just seem useless to a newbie like me. I am practising using these cheap rods but end each session with one of the Satincraft rods and they always seem better. The arc is more tolerant of my wobbly motion and the bead is smoother.
The cheap rods are good because if I can learn to use them I should be a better welder. But if I have to do anything serious I will use an expensive rod because there is a better chance I will get a good result and hopefully on the first attempt.

It's great when it works. I'm trying to reduce the amps (as suggested by Roy) but the cheap rods seem to need the high end of the scale with my current skill level.
--
Steven

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If you are wobbly, you might want to consider really bracing yourself and your arm. For a right hander, I have my students push the right hip against the bench, right elbow tight against the rib cage. Put your left forearm down on the bench, use your left hand to steady your right wrist. This allows you to tilt your head down and get up close to the weld bead from the side.
Another drill for a newbie is to position your arm as if you had a full rod on your work piece, then position your arm for 1/2 rod and burned rod at the end of the workpiece. You'll notice that your arm goes down more than it goes horizontally. Once you figure this out, it keeps the arc from getting too long.
Be sure to clean your helmet glass (better yet, replace with a fresh piece), and consider going down 1 shade for better visibility. For your 2.5mm and 3.2mm rods, a #10 lens is plenty.
Steven Saunderson wrote:

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Roy is giving you a #1 tip here.
I clean the slips and filter by dabbing with a spot of washing-up liquid and washing with warm water. Avoids accumulating scratches. You should be able to see very clearly in normal colour when the arc is running.
It takes quite a good (expensive!) auto-darkening helmet to give as good a vision as you get get from a well-cared-for traditional filter helmet (?) - the likes of "Speedglas" helmets and the like.
Rich S
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wrote:

I'm quite addicted to my (cheap but okay) auto-darkening helmet but I'll try a traditional helmet to check for any difference. My main concern with the auto helmet was possible eye damage but I haven't seen any problems yet.
--
Steven

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You would be quite amazed to try a large format (4x5"or so)with a NEW cover shield and a NEW filter. This goes double if you have any vision issues like glasses or bifocals.
Another trick is to illuminate the weld area with a large light, best is a 300 or 500 watt quartz work light. Flip the helmet down, wait 10 seconds for your eyes to adjust, the work area should look like a brightly lit moonlit night BEFORE you strike the arc.
Steven Saunderson wrote:

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This sounds great but I can't justify the cost at the moment.

I haven't tried this yet but I do like welding in the sunlight which probably gives a similar effect. It makes a huge difference with oxy work and improves the colour balance with arc welding.
--
Steven

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If you weld in sunlight, try to arrange things so your eyes have time to adjust. With a classic helmet and regular lens, you will need to wait perhaps 30 seconds for the eyes to adjust. Make sure the sun is not bouncing light inside the helmet or the eyes never adjust. You can shorten the 30 seconds if your helmet is in the shade and the weld area is in the sun. But once you get going, it's wonderful to be able to see everything in decent colors as well as all the weld puddle details.
My garage doors face due south, most stick welding is done with the doors open. I adjust the welding location to deal with sun vs shade.
Steven Saunderson wrote:

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wrote:

I put a pair of the cheapy 300 watt quartz halogen work light fixtures overhead, so they shine at 45' angles onto the welding bench.
Best thing I ever did. Now I can actually SEE stuff besides the puddle. No more going off course and running beads across bare metal off at an angle away from the join...blush
Gunner
"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner
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I've taken good note of this point. I don't have a bench so normally I don't have anything to steady my arm. Now I'm arranging things so I can brace my arm and sit down rather than standing up.
Thanks,
--
Steven

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All great advice, but this right here is the gem. I finally started to get a handle on using my stick welder by doing something like this. I took some scrap leftover from another project and started writing on it with my stick. Sentences, my name, etc. When I got to a hole in the scrap I just tried to weld right over it filling the hole. One thing I learned is one of my own limitations. If I can use both hands on my torch, clamp, gun I can do a pretty good job. I can't do a very good job one handed, but if I use both hands I can do passable work. It has taught me to clamp, tac, or use a magnet to hold all my work in the correct posititions even for quick, doesn't have to be accurate stick two pieces together work. That has probably improved my results as well.
I know. You guys know all this stuff already, but its fun for me. I've had a stick welder for nearly 15 years, and a cheap mig for almost 10. Only in the last couple have I started to be satisfied with some of my work. Only now am I getting good enough to realize how bad my equipment is. LOL.
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