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lorenzo

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Posts posted by lorenzo


  1. Yes the small rectangles are the electrodes, they are in the weld position as the picture is taken. they are pushing against the ends of the ring towards the clamp that is holding the ring. This is exactly how it looks when the ring is welded. the force and the amount they exert is controlled by a compression spring and it is adjustable from nil to the limit of the spring. I would guess that it's set to about 5 lbs of effort to move the electrodes against the spring.


  2. *scratcheshead*

    So, it's nonsensical to ask. However, I don't think that's the root of your question. Unless you're just asking because you're curious, you're thinking that varying both serves a purpose. Why is it you're trying to vary both? That question might have an answer. I don't know much about welding, so, I can't guess.

    Just trying to figure out what and how they do it on commercial units, perhaps they just limit it, I don't really know.

    That's an awesome bench power supply. I wouldn't carve it up for use on any dedicated project if you have any interest at all in hobby electronics (and if not, what'd you pay for it, maybe you'd wanna sell it to me in exchange for something.. lesser plus some cash?).

    I'll probably be using this thing to charge caps for a welder then, and maybe anodizing too now that I know it's just too overpowered, it won't need to be carved up since it has an output plug on the front of the unit. How fast do you think it would recharge the caps? Also will it charge the caps at whatever voltage I set the variac to, even if it's more than they can handle?

    No, you're looking for something that starts at at least 10x that capacitance. You'll need about 100-200 of those ones you linked to ($260-$520), and by the time you wire 'em all up, your distances will be too long, the wire will eat up much of your charge.

    And, I'd go with 150V or 200V caps, unless you're sticking to jewelry. (Caps should only be charged to about 2/3 or 3/4 of their rated voltage to be safe, and you'll be pinging them at 100-110V on some of the beefier stainless, no?).

    I think for ring welding purposes the needed capacitance might be smaller, those caps have exactly the same rating as the ones that power the mini pulse III. However that brings up a good point, how does ABI get away with having only 100v caps and also a 100v output from those caps? Could that be causing problems with their welders? The cap connected to #1 is a 250V 450uF cap and I believe the one for the pre arc is as well, all the others are 100v 3300uF.


  3. Here are a few pictures of the resistance welders at work, they are butt type welders. There are two pictures of the variable settings that are necessary to make consistent welds in different size and type of metal. there is also one picture of how the welding portion of the machine is set up with the electrodes and ring clamp. The weld you see being made there has about 80% of the strength of the ring, we can set it for welds that are stronger than the original ring itself, but from a production point of view it isn't viable.

    With a lap type resistance welder you would use overlapped rings similar to a riveted ring and squish the two ends together sideways, I believe that is the technique that Knuut uses.

    1673_thumb.attach

    1674_thumb.attach

    1675_thumb.attach


  4. Or, hrm. Depending on what you're thinking of, it might be possible, but if it's possible, there's no need to do it that way.

    There's no reason to split up the currents. And, each circuit has the same resistance (the resistance of the wire between the prongs... 3mm of 20G copper wire for example, is 0.000035 ohms, with 1 volt, you'd get 28,000A).

    Different circuits are only going to add up to an equivalent single circuit. If you want 11A, you don't need to switch on or off various other circuits, you can just dial in 11A, right?

    Maybe I've got you wrong. What's the issue you're trying to resolve?

    Just trying to figure out a way to vary both Amps and Volts, assuming it can be done.

    10A where? It have a wattage consumption marked on the back anywhere?

    If it can support 10A @ 140V, that's 1400W. That's certainly enough.

    You can use that as a wicked anodizer. Or, to charge a cap-based welder (so, you're looking at buying caps and a thyristor, and that's it).

    It actually was an anodizer, unfortunately it had a tendency to melt rings. So I thought maybe it would prefer to be a welder. It's marked 1.4KVA, weighs about 10 lbs and has a 12 amp fuse. I think this is it here, or very similar, slightly different serial #

    http://www.stacoenergy.com/PDF_Files/Drawing%20PDF/3PN1010B.pdf


  5. Hrm. Either I understood you correctly, or, I'm misunderstanding you the same way both times. That sounds like what I was trying to describe.

    Alright I'm probably the one misunderstanding then that's OK.

    What's the reason for not touching the electrode? Just that you don't need to, in order to weld? When you flick the switch, there's no adjustment of the electrode afterwards, right? Flicking the switch, with the electrode still not touching, still causes a weld?

    If the electrode touches the ring during welding the electrode gets welded to the ring, very inconvenient, that's where the high voltage pre-arc comes in it ionizes the gas creating a path from the electrode to the ring for the arc to follow. Come to think of it, this is probably what's not working on Freyr's unit it might be shorted out.

    Here's a link that may be helpful. http://www.greenaway1.demon.co.uk/tig.html

    Also, a bit tertiary, you cannot dial in both voltage and current.

    Voltage = Current * Resistance.

    3 variables. Resistance is set by whatever the circuit is. It's fixed.

    Can you swith to another circuit with different resistance? For instance 4 circuits at 1 amp, 2 amp, 4 amp, 8 amp each with variable voltage and the ability to switch between should work. If you could combine the circuits to make say 11amps(8+2+1) that would be ideal, could this work or is it a garbage idea? Is this similar to how ABI uses the several caps that switch on and off?

    Right. Gotcha. So what you're saying, is if you wanted to control the duration of the weld by some other means than mechanically applying and removing the electrode (in a tiny fraction of a second)... you'd have to crank up, and then crank down the knob, just as fast (which is also a mechanical process).. right?

    So you want some non-mechanical way of flicking that switch on, and off, in a precise, predictable manner?

    Should be easy either way. You just break the circuit, and insert your monostable trigger, that closes the circuit only according to a duration for which you set.

    Meanwhile, you can leave the dial set to whatever it's supposed to be.

    It's really such an easy hack, I don't know why all welders don't come with it. Maybe manufacturers want to be selling their "automated" units for a higher price.

    If everything works as I'm imagining it, it's as simple as cutting 1 wire, inserting $2 worth of components, and you're done.

    OK, this all sounds about right.

    *nod*. That's the problem with using continuous welders on finesse work. They're way overengineered for it. A cap welder, with a fixed amount of charge stored, is a great way to dial in what you need. The only problem is the voltage drops off as you dump the charge (but, that's usually what you want anyway, no?)

    If you're up to chopping apart a foot control's wiring, spending a few bucks at The Source, and using a multimeter, I can walk you through it.

    Or, if it's worth your while to mail it to me and back, I can try my luck with it.

    I'm pretty sure I won't be allowed to hack Jon's very expensive GTAW welder. :(

    I do have a small power source to work with. Marked as a variable autotransformer output DC 0-140V @ 10A. Can I do anything with this?


  6. Yep, about as thick as a toothpaste tube, here's a pic from a web review.

    http://www.pcper.com/image.php?aid=465&img=14-Inside_big.jpg

    I also have one of these laying about from an old project that I burned out on. But I'm guessing the voltage is way too low.

    http://www.solarbotics.com/products/cpag1.0f/

    Anyways I think you've got the map out of what I want in a welder a little skewed. Ideally I want to just dial in amperage, voltage and time. Hold the ring in a pair of grounded pliers, move up to(but not touching) electrode and nothing happens, hit a switch and instant weld. The foot pedal thing is available for extra cost in a thumb dial version. We have one at work, it still sucks. Think of it as like the volume control knob on an old stereo it goes from off through the minimum amperage up to a max that you can set beforehand. There's no way to have it turn on at say 10 amps because you have to turn it back down to 0 to turn the damn thing off.

    I've attached a pic of a few rings I welded up at work today using the GTAW, 16g stainless steel. The pictures aren't very good, but the best I can do with my computer still down. The welds were made at 5A, 75V which is the lowest setting possible on that unit. These welds took about 1-2 seconds each of power once I got the arc started, which took a lot of luck and finesse. Now that I've played around a little bit I think I could weld with it at 10 amps faster and better(less time= less heat build up) but there is not enough control usually I melt half the ring.

    1667_thumb.attach


  7. Yep, there is a point where the GTAW switch turns off completely and thin wires so that seems all good. The amperage requirements are seriously small compared to what you'd need for sheet metal, I'll fool around at work a litle today and see if I can't nail down an amperage for 16g stainless, welding anything thicker than that is silly anyways. The voltage would need to be variable between 20-100 for versatility, about 48 volts might work for between 22-18g, probably not well.

    The main cap in my psu is rated for 560uF, 450V, but it may be a little beefier than most.

    I'm gonna do some more research and then get back to you.


  8. Cynake:Lots to reply to, but I'm having a hard time voicing my thoughts. What I meant was that you don't increase penetration simply by having excess voltage because you end up vaporizing metal.

    GTAW welders don't have an on/off type switch, usually it's a foot pedal that increases the amperage as you depress it farther. Neither do they require filler material. Unfortunately they are also very overpowered for the job and the adjustment is not precise enough. For instance the one you posted can output 130 amps in 1 amp increments. I estimate that 16g rings would require less than 5 amps but in much finer increments especially to do down to 24g. It also does not have the high voltage pre-arc required to start the weld.

    MIG welders are just generally unsuited, designed for a totally different type of welding.

    Resistance welding refers only to a type of weld that uses the electrical resistance of metal to generate heat for a weld, it doesn't work well on metals such as silver, copper or gold. generally it employs two electrodes positive and negative that contact the metal one on each side of the area to be welded together. It does work, our maille machines use resistance welders and master knuut does as well. There are two types of resistance welders, butt welders and spot(lap) welders, unfortunately they both have the same flaw, they either squish the weld area or make an incomplete weld.

    The better form of welding is the type that ABI uses, it is basically GTAW welding, which is very similar to arc and plasma welding. With this type of weld there is only the positive electrode, which does not necessarily touch the workpiece and a ground clamp which does. In GTAW and plasma welding the electrode is non-consumable and generally made of tungsten. In arc welding the electrode is consumable and is made of a filler material.

    As an aside, it seems to me that the caps from old PC psu's might be suitable for welding, those are definitely cheap and plentiful.

    Freyr:I know it sucks to get a lemon, I hope you get it working or get a replacement. I've logged many hundreds of hours welding with ABI welders and when they do work they work very well. You will be able to weld 32g no problems, I've done it. That said I've also welded rings with GTAW, mig, resistance welders and torches. Out of everything GTAW was the hands down winner for best welds, but the commercial units were too powerful even to do 1/8" thick wire as cleanly as I would have liked.


  9. Penetration should be affected by how many capacitors you're discharging. You need more heat, so you need more charge. Higher voltages on small pieces are just going to vaporize metal.

    Exactly, you don't actually get better penetration, it just seems that way because you're removing and/or distorting more metal.

    As far as how other professions do it, they use mostly silver and gold, requiring between 15-30 volts to weld and generally smaller guages. Stainless usually needs 30-60 volts and with all caps running.

    Some of our welders seem to run fine, some develop problems, it's about a 50-50 split. The solution Jon came up with is to just send the defective welders back and tell ABI to send him NEW ones, or else. This solution may or may not be effective, depending on how much clout your "or else" carries.

    Cynake: As far as I know there is no reason to stick with a cap based welder, but a resistance welder is not optimal for production speed and weld quality. The ideal welder would be to copy a GTAW on a smaller scale with a timer to allow for precise amounts of current over a set time.

    I have seen rings welded in this way on proprietary machines and the welds are pretty much perfect. If you know how to set up an appropriate power source and electronics everything else should be standard GTAW equipment. If you could find a cheap GTAW unit with a high voltage pre-arc then it might be a simple matter of adding a timing mechanism.


  10. Hey, I've been meaning to respond in this thread for a while now but I've had a hdd crash.

    So anyways, yes these are essentially the same problems that we have been having with some of our units. Basically the high voltage pre-arc is not functioning. If you send it back to ABI for testing and repair they just hook it up to a multimeter and run it automatically for a bit to make sure that the weld is firing and then tell you there's nothing wrong with it. As far as I can tell they do not actually bother to weld anything with it. This is the reason that Jon is considering discontinuing these welders.

    Cynake, if you can make a cheaper more reliable welder for less, do so. Your odds are good that you will have an immediate buyer for as many as you want to make.

    Freyr, first of all you shouldn't need to weld 16g@100volts, 60-70 should do it. Make sure that the ceramic is completely clean and that your electrode is properly sharpened for good weld penetration. It is exactly the same procedure for sharpening a TIG electrode and if you don't know how

    http://www.millerwelds.com/education/articles/articles83.html

    Expect 6-8 overlapping welds on a 16g ring to cover the full perimeter of the cut.

    Also I was reading in some other thread that you wanted to hook up an intermittent switch for gas welding Ti. If the mini-pulse you have is anything like the ones we took apart here at TRL it will actually already have the switch installed in the guts of the welder. You don't need the stupid regulator and gauge on the welder since you need one on the tank anyways, just hook up the lines and off you go.


  11. Tungsten itself is not any more toxic than any other heavy metal, like gold or silver...just don't eat or breath it...it's twice as dense as lead, and exactly the same density as gold....personally, I think it's beautiful...a deep shiny grey when finished.

    Kodiak-

    Just to be clear, although tungsten itself is no more toxic than gold, there are many much more toxic metals(such as thorium) routinely added to tungsten and it's alloys.

    Also unlike other heavy metals silver is completely nontoxic to multicellular organisms. Silver does cause the condition argyria, which while not dangerous is not very pretty and not curable either.


  12. Actually I think the only real restraint shown was by me not posting the pictures with the pants on my face on teh internets... yet. Also you might notice I left my boxers on.

    But yeah, people are always commenting about my restraint just the other day Jessica said I had a whole order of restraint.

    On the contrary, Jessica Alba has quite publicly said that she thinks there is nothing wrong with girls sleeping around as much as they like, and that she likes to a lot. She even sent out a list of rules for all prospective one-night stands, on national television. Including classy items like, the guy has to be gone in the morning, and not clingy.

    This would explain the ragged 2 foot gash in the crotch of said pants, my first guess was "shark fanboys with wirecutters".

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