arc welder/spot welder? Answered

Can an old small arc welder be used to make a spot welder? It's a 60 yr. old Grindl. A stamping on it says input amps 20, sec. amps rated .80- 80, welding volts 20, max open cir volts 80.

Question by hjones47222222 3 years ago  |  last reply 3 years ago


MOT spot welder?

I want to build an MOT spot welder and ive already cut the wiring out of the transformer but i noticed while doing so i scraped off what seems to be the coloring off the primary.  Will this affect it in any way? Also, i can really tell the power of this transformer? can anyone help?

Question by dask13 7 years ago  |  last reply 3 years ago


Diy Spot Welder

Hello, this is my first post here at Instructables. I will get straight to the point. I plan to build a diy spot welder. However, in most of the diy spot welder projects I have looked at, including Hack a Day and Instructables, a MOT (Microwave Oven Transformer) is used. The secondary is rewound with thicker wire, and the transformer is used to step down voltage and step up current. I have heard that these transformers can supply as much as a kiloamp at very low voltages. However, I do not own a MOT, they are too costly to buy, and I do not want to retrieve one from a microwave because- A) Nobody happens to be throwing away a microwave in my area. B)The guys who own the scrap metal and thrown away appliances will only give me a microwave oven at a hefty price. C)I would prefer to live a very long life, and do not want to gt myself electrocuted poking around the innards of a microwave. SO, I did a thorough search, and found that some people made a welder from a stereo amp transformer. Again, I did not own one, but what I did own was an ultrasound generator that was supposed to drive away rats. After making  bloody inroads into it`s innards, I found a transformer quite a bit larger than the regular step downs. It is 5 cm long, 4 cm wide and 1.7 cm tall.  Input voltage is 220 volt AC from the mains, at 60 hertz. Output is 12 volt AC at a maximum of 300 MA. Speaking from experience would anybody please tell me whether this is suitable for a spot welder? Please ask me for additional information, including pictures, if required. Thank you.

Topic by TheLightningConductor 2 years ago  |  last reply 2 years ago


Computer UPS backup transformer into an welder OR spot welder ??????

I have some transformer from my UPS. i want to make it welder.. watch this videos.. Do not talk about microwave ovens transformers . i don't have microwave transformer. can we make it ??? 

Topic by ishan udyoga 5 years ago  |  last reply 3 years ago


Can a ARC WELDER be converted to a SPOT WELDER?

I have this ARC welder which puts out 50 AMPS, flip the switch gives you 80 AMPS. I would like to spot weld thin metals for a project i am working on, and by all accounts on what iI have seen on the INSTRUCTABLES all I would need is the copper tips attached to the clamp device

Question by yeagerxp 10 years ago  |  last reply 5 months ago


Making a better spot welder....

I am in the process of building a proper spot welder from scratch. Proper more in terms of the electrical and electronics part but not so much in looks ;) My problem now is to find useful info on what power levels are required for certain tasks. I realise that welding thin sheet metal won't need as much time and amps as welding a 3mm stainless steel rod - but what is a "good" power level? I watched a bunch of Youtube videos showing various approaches but for many it seems the producer had no clue about the difference between creating a short with burn marks and a weld... Especially when it comes to creating battery packs with a capacitor bank as the main power provider you can clearly see the device burns holes but does not really create a welded spot. On the other hand there are a few videos showing spot welder made from a MOT that seem to produce a proper melted and welded connection. When I used a proper spot welder at work it had timing settings, power levels and even a feature to adjust how the current rises.... Not to mention a gauge that checks the pressure and only activates the welder once the set point is reached... There is a ton of info out there that after a thausand words still tells you nothing you need to know :( So is there anyone here who can shed some light on the actual process of spot welding in easy words for everyone to follow? I am aiming for a max output of around 400A @ 1.5 -2.5V with an adjustable shunt in the transformer core to avoid oversaturating the core. In a later stage I will add power control over the primary side but until then it is only time control, from a few ms to a max of 5sec if the damn controller arrives one day. Big questions: 1. Is a power control really required or is it possible to cater from thin to thick just by using different timing settings? 2. Since a MOT is used for the power supply: Is it better to leave the shunts out to fully avoid saturation by adding an inductor in line with the primary or is it still better to adjust the shunts under load to get the maximum power possible? 3. Aluminium and other materials benefit from using AC but would be good to have a DC output too, if so then what materials really need DC? 4. All I could find is that copper is used for the electrodes, due to resistance and heat transfer - are there other options apart from using copper? 5. Tricky one: I would prefer to use the secondary winding as the new primary to avoid core saturation and to lower the load on the power outlet. Where can I find very thin copper bar material that I can coil up and insulate as I would quite a few more turns to get at least 1.5V out of it? Just don't like the idea of spending days rolling a copper bar thin enough.... For the advanced model at a much later stage: Of course I would like to be able to use a proper power control instead of a motor dimmer or similar. For obvious reasons an inverter microwave jumps to mind. But after checking one I noticed one big problem: there are not really that many windings on the primary of the transformer at all! Same way our modern switchmode power supplies only use a few turns these things do exactly the same. After some quick and dirty initial tests I realised that even a single turn of thick wire already results in over 20V on the secondary. Wasted a lot of wire and time making one coil with 5 turns less and one with 10 turns less but the system would not even start with it. Seems these things need a fixed inductivity on the primary that matches the frequency used, in my case 36kHz. Would love to overcome this problem so I can at least go down to a single turn to get under 5V on the output side as space is non existing on these inverters. Can I cheat? Do I need to change the circuit to match the new primary coil? Am I thinking in the wrong direction altogether here? And added bonus would be to be able to adjust the power from around 15% to 100%, so far the electronics don't allow anything below 45%. Is it possible to drive these inverters in resonance? (Ok, off topic as I would like to use this for a beefy HV supply) Last thoughts: I know people already used Arduinos and Raspberries with displays and all but so far I have not found anything that shows how to do it properly. Seems all that counts is to create connection one way or the other and to call it a spot weld even if it is just a burn hole from discharging a capacitor bank through a needle like electrode.... For obvious reasons I don't want to create just another spot welder that makes a professional pee himself laughing about it. IMHO nothing beats personal experience with something but I don't really like wasting my time by trying what other people alread did a long time ago. So if YOU already built a MOT based spot welder and used for more than a few spots I would love to hear from you! Let me know what type you used, what problems or shortcomings you noticed or where you feel it just does not work out the way you expected it. From simple things like always getting bad sparks or arcing, over how easy or hard it is to get consistand results to whatever really annoys you while using your homemade spot welder. I hope that your feedback here will help me to write an Instructable on building a spot welder that does what you expect it to do, not once or twice, but everytime you use it. Mechanics might vary the same way the electrode style does but the weld should always be a proper weld that won't tear apart ;)

Topic by Downunder35m 1 year ago


small hobby resistance/spot welder?

I want to weld small steel wires (the size of guitar strings - +/_ .035) to make small sculptures. Solder works, but is not fast or strong enough. Can I make a welder to run on 115VAC?

Question by Dweevil 9 years ago


Could I use a 550w PSU as a welder instead of two microwave transformers?

Question by jking1984 10 years ago  |  last reply 9 years ago


Need Help With A Mini Spot Welder

I've been trying to gather information to build a welder for a special application. The use is for welding the commutator tabs and magnet wire that passes over them for small DC motors. While there are specialized and often automated welders made for this purpose, they are both large and very expensive and really intended for industrial users. I have been able to get small bits of information as to how others have done this, but it's been difficult to get the whole project laid out (there is apparently some "secrecy" involved here!?). The materials being welded (soldering isn't a preferable way to make this connection...these motors run hot and very fast) are the brass commutator tabs (approximately .030" thick material about .060" wide formed as a "U") and the copper magnet wire used to wind the poles that then passes over each brass tab...from #23 awg to #28awg. From what I've been able to gather, people have done this on a "homebrew" basis using 6V automotive battery chargers/starters that can deliver around 30 amps or more. I have very little knowledge of electronics and none at all about welding and circuit design, but am looking for information on how I might proceed after sourcing the charger/starter. I'm guessing that the "negative" cable would be adapted to use as a clamp at the commutator and would also double as a heat sink to prevent damaging the commutator and that the "positive" cable would somehow be adapted to hold some sort of fine rod that would touch each com tab to complete the welds. -Maybe a footswitch could or should be used to start/stop the weld? -Is the positive cable simply used to hold a rod for the "spot weld"?, or are there other pieces that need to be added? To my mind, it would seem that simply touching the positive to the commutator tab to make the weld and complete the circuit would simply trip a breaker at the panel or any protection device on the charger(dead short!?). -Any other information or thoughts? Thank you in advance -john

Topic by havlicek 10 years ago  |  last reply 10 years ago


Large electrolytic cost/size "sweet spot"?

I'm in the process of sourcing components to build a capacitive discharge battery tab welder - there are a few designs out there on the internet from this one: http://www.philpem.me.uk/elec/welder/ which I like because it's nice and simple, to this one, http://www.youtube.com/watch?v=hxWo8ko2k2A which is gorgeous but complicated. So anyway, first off I want to find some large capacitors. I'm wary of using car audio stiffening capacitors as it looks like they don't last very long for this purpose, although they can be obtained relatively cheaply, and I can't afford large standard type electrolytics which cost an arm and a leg. I did have the idea that there must be a "sweet spot" in terms of cost/size where I can build a bank of capacitors without breaking the other sort of bank - it looks like probably being around the 20 x 47,000uF (like this design uses: http://www.pittnerovi.com/jiri/hobby/electronics/welder/index.html ) mark, but I wonder if anyone with more recent component purchasing experience than me can provide some pointers? The voltage rating needs to be in the 20 to 30 volt range. Oh, and when I've finally built one, I'll post an instructable, I promise! My version is likely to be rather more analogue though as I don't know anything about microcontrollers.....

Question by throbscottle 8 years ago  |  last reply 8 years ago


robotic arm arc welder

Is it a robotic arm capable of arc welding feasible for a diyselfer ? I spotted some robot arms for cheaper than 200 $ over the web . Vantages for the operator would be no weld fumes breathing , no uv rays and such ..

Topic by gabdab 5 years ago  |  last reply 5 years ago


i want to make battery tab spot welder how can i make?

Question by ustech 8 years ago  |  last reply 7 years ago


rectify electricity before transformer?

Can you rectify the US mains (120vac, 60hz) as it, and used the pulsed dc to feed into a transformer and get a dc voltage out of the transformer? I'm asking this because it would be much much more efficient for high current situations. Here's my specific situation:I want to build a capacitive spot welder and a capacitive discharge cutter in an all in one device. To charge the enormous capacitor rapidly (1.5 farads in my case), I need a very high current power supply. I'm using a modified microwave transformer that was rated at 1kw, and it is now modified so that it outputs 12 volts AC at around 80 amps (probably less because of losses). This must be rectified to charge the capacitor.Assuming a perfect transformer (for arguement), it would have:120volt, 8.34 amp input12volt, 83.34 amp outputthe following is with full bridge rectifiers, assumed voltage drop: 1.4vIf the power was rectified before the primary, the loss on the bridge rectifier would be: 11.67 wattsIf the power was rectified after the secondary, the loss on the bridge rectifier would be: 116 wattshuge differenceso once again, the final question is: Does rectified input of a transformer = rectified output? Does the 120hz pulsed dc (as opposed 60hz ac) matter? Could this setup charge a capacitor?

Question by guyfrom7up 9 years ago  |  last reply 2 years ago


Battery tag / tab welder from a camera flash

About a year ago I found a project somewhere to turn an old camera flash into a spot welder for small batteries. I found an old flash gun in my spares box and I wanted to have a go at building a spot welder from it but I can't find the weblink. Does anyone have any suggestions ?

Topic by scubascooby 9 years ago  |  last reply 9 years ago


capacitor bank questions.

Hello all, this'd be the first post i've ever made, and may be in the wrong place....... edit- i guess it was in the wrong place, since no one replied.... so i'll try here.... i'm tryin to make a cap bank from 30+ flash cameras (possible? possible outputs? how do i calculate that?)  and i have some question/problems. is it possible to take a bank like the above and use as a spot welder?   if so, how would i trigger the spark without the trigger becoming the spark gap?  another possible use i have for it is a rail gun...... theoretically, if counter evidence isn't provided by all of you much more tech inclined ibblers a second concern is that the caps come in at least three different micro farad ratings. would one explode if it's rating is lower than the higher ones?  (the ratings are between 80ish to 150 ish (don't remember)) i rather need the weilder for a possible steampunk project that i just bought a bunch of metal junk for....(knowing me though, i'll never get around to doing it....)

Topic by badideasrus 8 years ago  |  last reply 8 years ago


What kind projects can I make with this BIG transformer and its other parts? ONEAC Power Conditioner transformer

Hey... I'm new here and I will like to say that I like many of the cool things people are doing in this site and I will like try making some of your ideas someday...And thanks for posting them... =) . Ok I have a power conditioner that has a big transformer and I wanted to know what I can make with it. This is the spec on the unit - BRAND is- ONEAC model# CS1110 its 50/60 HZ 1 phase. Power input 120 VAC 8.8amp Output 120 VAC 8.4 amp . Its a really heavy piece. What I will like to do is make a spot welder since I need one but I'm not sure if I can use this transformer to make it. maybe an Induction heater,Welder, I'm in for experimenting with something new...I don't want to take this apart yet until I know what can be made with it first because I know it may be worth alot more if I just sell it. I seen alot of cool things done made with transformers..Any suggestion and ideas will be appreciated . Here are the pics. thanks

Question by PitStoP 10 years ago  |  last reply 10 years ago


Where can I find 4 AWG wire? Answered

I got my microwave, and now I want to make a spot welder. Any recommendations for where to find 4 AWG wire, or something similar?

Question by CameronSS 10 years ago  |  last reply 8 years ago


induction "furnace" from microwave transformer?

Hey guys I've seen around the net that it's fairly easy to make a spot welder from a micro wave transformer /micro oven transformer. So I was thinking if it's possibly to use the same idea to make a induction furnace? I would like to use it for melting/ casting aluminum (...and possibly metals with a higher melting point... if possible) any idea if it's possible.. and how to?

Question by lordl9999 6 years ago  |  last reply 1 year ago


Microwave Oven Transformer arcs too small- about half a millimeter

I have two microwave oven transformers (MOTs) that I am currently working on, and I have taken one of them apart to make sure of the wiring of the coils. I am fairly confident in the wiring of the whole system. I have the original primary and secondary coils, both made of copper. The transformer is one of the larger ones I have seen, and its wattage at about 1000W. I know it is not popping the breaker because the hum is always on. I have read through many of the instructables out there about MOT's, so I understand it pretty thoroughly, but the arcs on the instructables I've seen are several inches long, and my arcs are about half a millimeter. I really wouldn't call it an arc at all.  I have the common wall output of 110 VAC, 60 Hz going into the primary coil, and the ground is attached to the MOT block itself. One of the secondary output wires is connected to a capacitor bank of 3 MOC's in series, and I have the other output on the end of a PVC pipe which I touch to the opposite end of the capacitor bank. What am I doing wrong? 

Question by Technicolor 6 years ago  |  last reply 6 years ago


where to find temp sensor for 18 volt batteries? Answered

I  work  for a  company that  has  a large  amount  of   cordless drills  adn saw alls  and power  tools. I  have been ask to   see what  it takes to repair the    battery  packs .  I have  a few  questions  i would like to ask if  someone  can help me with  ? 1.  Where  can   one  find  the  temp  sensor  switches   that are  on  the    milwauki red lithium  and   dewalt  18 volt  nicad  battery  packs. 2. does anyone  have  a better way  of    building them other than  soder  each  battery.? I found  a battery spot   welder  but it is  like  $5,000 bucks.  Take  a long time   to pay  for that.   I  soder  my  rc  battery  packs   but  just looking for a better  more cost effective way. Thnaks for any help anyone  can  give. Andy

Question by andy1917 6 years ago  |  last reply 6 years ago


welding cast iron to mild steel

Welding cast iron to mild steel is for the most part done with ornamental iron such as gates and fences. the ornaments are typicaly cast iron such as spearpoints and fit over the top of what ever square tubing size ect you are working with. If you weld say with a mig welder in the normal mannor you rweld will cold roll and ball on you leaving a poor appearance that you will have to spend time grinding to make look good. Fortunatly it is not a matter of strenght or how much penetration ect. It is just ornamentation but must look good. Now take your mig welder with say 035 wire and use pure argon..(less spatter). Turn your welders heat up somewhat past what your normanl setting would be for what ever thickness you are using. Use breif spot welding like techniques overlapping as needed. You will find that this makes a good wash bead with no undercut or cold roll. The argon gas helps to keep down all the extra spatter welding cast iron to mild steel seems to cause. Larger peices such as caps for say 4by4 gate posts or fence posts, i preheat as uniformely as possibly to just under cherry red then weld as described. It welds badly because cast iron is actualy dirty, literaly with particles of dirt in the cheap castings, wich the ornaments are. Not haviong the need to be anealed or nodular for instance. If the welds are not going to show then you dont have to do this. It will still weld, just do not expect the clean perfect welds you are used to.  And NO I do not have PICS AND I dont own a digital camera nor do i know how to use one let alone put them on a computer.

Topic by beserker 7 years ago  |  last reply 7 years ago


Why does my MOT have a wire from the HV coil connected to the casing? Answered

Hello, I'm busy with making a spot welder from a MOT (microwave oven transformer), but I'm not really sure why and how to ground the MOT. In the picture you can see that a wire from the high voltage coil is connected to the casing which I find to be Really odd. That wire is not really a problem since I'm going to remove the secondary windings, but I'm just interested in an answer to that. Another question is, is it necessary (for performance) to have the MOT grounded? or is it Only for safety that the casing needs to be grounded? (no matter what the answer is, I'm still going to ground it, so it's not necessary to have safety discussions here) thanks in advance, Electorials

Question by DELETED_Electorials 7 years ago  |  last reply 7 years ago


Who wants to be on a Game Show?

I was just sent this link by a friend: Discovery Science Game Show Here is a brief description of the game show:Producers for a Discovery Science Game show are looking for contestants. Contestants can be a gonzo engineer/scientist or just a high-energy, creative, fun, builder!They are looking for garage warriors (builders, scientists, inventors, engineers, carpenters, welders, mechanics, architects, etc...) who love to invent new gadgets, build robots, racing power tools, weld together bizarre machines that drive, fly, climb, shoot flames or launch projectiles. This Game Show is for thinkers, dreamers and doers, who are eager to let their inner MacGyvers be seen and ready to collaborate with a team of other builders.It looks like it was made just for our kind!! Now, who is going to try to get a spot on this show? If you do, be sure to let us all know!

Topic by jeff-o 10 years ago  |  last reply 10 years ago


rectify electricity before transformer?

Can you rectify the US mains (120vac, 60hz) as it, and used the pulsed dc to feed into a transformer and get a dc voltage out of the transformer? I'm asking this because it would be much much more efficient for high current situations. Here's my specific situation:I want to build a capacitive spot welder and a capacitive discharge cutter in an all in one device. To charge the enormous capacitor rapidly (1.5 farads in my case), I need a very high current power supply. I'm using a modified microwave transformer that was rated at 1kw, and it is now modified so that it outputs 12 volts AC at around 80 amps (probably less because of losses). This must be rectified to charge the capacitor.Assuming a perfect transformer (for arguement), it would have:120volt, 8.34 amp input12volt, 83.34 amp outputthe following is with full bridge rectifiers, assumed voltage drop: 1.4vIf the power was rectified before the primary, the loss on the bridge rectifier would be: 11.67 wattsIf the power was rectified after the secondary, the loss on the bridge rectifier would be: 116 wattshuge differenceso once again, the final question is: Does rectified input of a transformer = rectified output? Does the 120hz pulsed dc (as opposed 60hz ac) matter? Could this setup charge a capacitor?

Question by guyfrom7up 9 years ago  |  last reply 9 years ago


newsletter Steampunk Rifle, Printing Press, Drainage Luge...

Aug 7, 2008 Sign-up for this newsletter: function openSubscribePopUp(src){ var emailValidate = /\w{1,}[@][\w\-]{1,}([.]([\w\-]{1,})){1,3}$/ if(emailValidate.test(src.value) == false){ alert("Please enter correct email"); return; } window.open("/newsletter/newslettersignup?email=" + src.value,"newslettersignup1","status=yes,scrollbars=yes,resizable=yes,width=420,height=250"); } Welcome back! The Horny Toad Invent-a-Sport Contest closes this weekend! Submit your crazy new sport now to win hundreds of dollars of clothes from Horny Toad.Also closing this weekend: voting for the Instructables Book Contest. Help choose what Instructables get mentioned in the book!Everyone loves pie! Enter our Pie Contest, share your favorite recipe, and win an excellent pie cookbook to help you get your just desserts Build a 4 Color T-Shirt Printing Press by Progfellow Drainage Luge by pbshoe Quickly Multiply, Wooden Style by joshf Steampunk Dystopian Sniper Rifle by gmjhowe 4 Uses for a CD Spindle by msolek Magnetic stripe card spoofer by powerpants Skateboard Frame by ryry Self Watering Mini Garden by RomanH Make an Instructables Robot Plushie! by jessyratfink DIY Bike Panniers by trebuchet03 Portable Solar Energy Generator by charlitron Perfect Peach Pie by linuxmom Voting closes this weekend! Top 10 new uses for LEDs Mmm... pie The ultimate workbench top! by poptones How to Make a Pie... That Turns into a Cake by locodiego Homemade Spot Welder by jds1969 Breathalyzer Microphone by randofo Now go make something awesome, and I'll see you next week! - Eric Sign-up for this newsletter: function openSubscribePopUp(src){ var emailValidate = /\w{1,}[@][\w\-]{1,}([.]([\w\-]{1,})){1,3}$/ if(emailValidate.test(src.value) == false){ alert("Please enter correct email"); return; } window.open("/newsletter/newslettersignup?email=" + src.value,"newslettersignup2","status=yes,scrollbars=yes,resizable=yes,width=420,height=250"); }

Topic by fungus amungus 10 years ago  |  last reply 10 years ago


Need Help in Building DIY LiFePo4 battery pack

Hello all, my wishes to everyoneam very new to this Electrical, Batteries and DIY, with the help of google i can gained little knowledge with that i could able to gather products to build my own electric scooter (1500W 60V HUb Motor and 60-72V regenerative controller with Daly LiFePO4 60V 45A Comm BMSactually am planning to Build 60V 36Ah LiFePO4 Battery Pack Using 19S6PBattery : LiFePO4 32650 3.2V 6Ah BMS : Daly LiFePO4 60V 45A Comm BMS Controller : 60-72V 1500W 35A am confused when times comes to assemble the battery pack, pls help and guide me with appropriate diagram or chart for 19S6P pack, help me how to connect batteries in series and parallel along with BMS so that i can build my first battery pack with out no mistakes Do i have use capacitors while connecting batteries, if so provide me the type already bought the battery tab spot welder from my friend for reference i have attached pictures of the products i mentioned and bought already please don't mind if i asked too much help/suggestions, want to make my own DIY battery pack by learning ad gather information about battery pack and build one one in perfect way Thanks in Advance

Topic by tejeyes 4 days ago


Electrolytic vs supercap for CD spotwelder?

I need to make a cheap spotwelder to rebuild some battery packs(e.g,. welding thin nickel strips).My options are:(a) Try to find most of a farad at up to 25V or so on eBay. This could take a while. (Buying new electrolytics in the 0.1F range and above at these voltages is pretty expensive.)(b) Go for supercaps from Digikey (e.g). They've got some 5V 1F models for only a few bucks, and some "fast-discharge" ones for 10x more. Of course, if I go for more than 10V or so, I'll have to build some sort of charge-balancing circuit around the series caps, and I'd rather not unless it's really the best way to go--- though it might be as simple as a resistor in parallel to each cap.(c) Try one of these weirdo "digital supercapacitors" that are all over eBay for the crowd who fill their entire trunk with stereo amps. These look like they're rated at 1-5F at 13.8V and (I would hope) include some sort of charge balancer. Dunno if they're suitable for the sort of instant-discharge I want for a welder, though.I'm having difficulty figuring out:(a) How fast a discharge I need for a spotwelder anyway; I'm going to be using an SCR to trigger it and presumably want the lowest-inductance arrangement I can get, but are we talking milliseconds or microseconds?(b) What can I get out of a supercap? Milliseconds or microseconds? I haven't worked with supercaps before, and most people who seem to be designing circuits with them are using them as batteries.Other random questions:My reference design had 0.5 to 1F at 0-25V through a 600V 50A TO-65 SCR; whatworries me are things like http://www.avxcorp.com/docs/Catalogs/bestcap.pdf,whose page 3 shows that non-ultra-low-ESR supercaps (e.g., theaffordable ones) seem to have virtually no capacitance for pulsewidths of 10ms or less. (The BestCaps in that datasheet claimsomething like 60% of nominal instead, which is pretty good!)I dunno how narrow the pulse width needs to be to get good welds,but I'm guessing pretty narrow---for example, one guy claimed inhttp://www.philpem.me.uk/elec/welder/ that just the difference inputting the SCR on the low side and not the high side (so the triggerfor it didn't have to go through the wires, electrodes, and workpiece)worked a whole lot better, which implies to me that he might betalking microseconds. But I just don't know.]Of course, I also don't know whether I need 0.5 F at 10V or 1F at25V for the things I'm considering.Not to mention---the 50F caps at http://dkc3.digikey.com/PDF/T072/P1354.pdf(some of which claim ESR's of 0.025 ohm at 1kHz) have these skinny little0.5mm leads on them. How in hell would these leads not be vaporized if Icharged up the cap and then shorted it, as a spot-welder would be doing?(And sure, I could try to attach #4 copper wire to them---somehow---andsend that to the sharpened tips on my welding electrodes, but boy I feelsilly doing that---seems like whatever part of the cap's leads aren'tattached to the heavy wire will just evaporate when shorted, if they canreally dump that kind of current, even if it -is- just for milli-to-microseconds.)The Instructables site has some rambling about using supercaps for CDspotwelders, but it's just rambling---nobody who's actually built oneusing them, for example, or who seems to talk about discharge rates,etc.

Topic by HilaryGage 11 years ago  |  last reply 11 years ago


Yuri's Night Bay Area: updated science/tech/art lineup announced

Prepare for Liftoff! www.worldspaceparty.org Get ready for something entirely different. On April 13th the Bay Area joins the world in celebration of space exploration in a unique convergence of artists, scientists, astronauts, performers and musicians. Yuri's Night is a commemoration of humankind’s first venture into space, by Russian Cosmonaut Yuri Gagarin. This gathering bridges national, cultural, generational and social barriers to ignite excitement about what is new on the horizon in space exploration and to remind us of the magnificent feats humanity is capable of. Yuri's Night Bay Area will be held at Moffett Field in the NASA Ames Research Center's massive SOFIA hangar, home to the world's largest aerial observatory. Our host for the evening is pioneering space traveler Anousheh Anasari, the first privately funded female to reach orbit. She is joined by Dr. Chris McKay, world renowned expert in astrobiology and terraformation with the Space Science Division of NASA Ames Research Center, as they welcome you to a dazzling array of interactive art installations and science demos, interwoven with musical and acrobatic performances by some of the world's finest entertainers. Cutting-edge interactive technology and live demos will include: Neuro feedback games and visualizations including Telekinetic Asteroids and Mind RipplesExplorations of the world through NASA World Wind and Gigapan, the high-resolution panorama projectPortals into Second Life and Burning Man Earth, Google's Black Rock City browserA roofless stargazing lounge, with an exceptional telescope provided by NASASquidlabs' Instructables and ground-breaking kite technologyScience demonstrations and innovations from the worlds of robotics, engineering, biology and astronomy, will also be on display: A talk and interactive demos from a senior SETI scientist on efforts to detect earthquakes from spaceExplorations of Techgnosis by Erik DavisInteractive next-generation science data visualization software from NASA Ames' Astrophysics DivisionRobots from Justin Gray, Carnegie Mellon University, and NASA, including the next generation of roversExclusive heavenly imagery from SloohDisplays of microbial fossils, live microbial mats, and magnetic and fluorescent bacteriaASME's human-powered vehiclesEngage with space-inspired and technology-infused art installations, including: StarZipper, the 200 foot high installation powered by LEDs and Helium created by internationally renowned artist Michael Light and collaborator Dave RattrayPeter Foucault's self-propelled motion sensor Drawing RobotsSpot Draves' collaborative evolutionary high-definition visual algorithm generator, Electric SheepDynamically inflating sculptures by AKAirwaysHypKnowTron and ChakraTron, the interactive light sculptures by GaspoExperience rare video works documenting art in space: Matières Chorégraphiques by Kitsou Dubois, celebrated French dancer, choreographer and artistic director of Ki ProductionsProjects from the Zero Gravity Arts Consortium, Lowry Burgess's monumental project The Seed of the Infinite Absolute, Lorelei Lisowsky, and Frank Pietronigro's 'Drift Painting' in microgravityMeet Japan's space artist Ayako Ono and watch Jean Luc Soret's Space Art videos, direct from Paris's International @rt Outsiders Festival.The Documentary Dome, featuring our planet's greatest space documentariesWitness awe-inspiring space-themed performances by an armada of acrobats and dancers, featuring: KC Bella Fuega and Spiral Hoop Dance (orbital hooping and bellydance)Flowtoys (celestial light performance and UFO flowplanes)VigilAntiUP (intergalactic stilting)A Parade from the Future (with cutting edge Bay Area circuit benders and other worldly creatures).Live dance and acrobatics fused with audiovisual performances, will be coordinated with a world-class lineup of live electronic music: PLAID - Warp Records, UK TELEFON TEL AVIV - Hefty Records, Chicago (special early evening set) BLUETECH - Aleph Zero, Native State, Portland OOAH + BORETA - Glitch Mob, LA/SF SUTEKH - Context, Soul Jazz, Leaf MR. PROJECTILE & JONAH SHARP (aka SPACETIME CONTINUUM) - Merck, Reflective, Astralwerks RD - Designed Disorder, Glitch Mob, LA WELDER - Cyberset MOZAIC - Nexus DR. TOAST - False Profit Music environs will be complimented by a team of visual artists -- including KOSHO, CELESTINESTAR, RECURSIVEVIDEOLAB and VIBERATION -- spinning light into space throughout the night. Meanwhile, outside on the tarmac, the SPACE COWBOYS will have their own dynamic lineup of djs aboard their interstellar party transporter, the UNIMOG. Also on the tarmac will be Playaflies and Rabbit in the Moon's outside VJ set PLUS large scale sculpture and multimedia installations from the bay area's finest and beyond. This year’s theme is the greenification of space. The event is bio-diesel powered, a variety of organic food and drink will be available, waste products will be composted and recycled, and one tree will be planted for every ticket sold in an effort to offset the event's carbon emissions. Come join us in celebrating the accomplishments of mankind on a collective cosmic journey to the depths of space and beyond. Brought to you by Nexus, Symbiosis and so many others. *********************** Friday, April 13th, 2007 Event opens at 6:30pm NASA Ames Research Center* Moffett Field, Mountain View, CA, 94035 Tickets are on sale now. Limited $30 presale tickets still available, but not for long! Purchase advance tickets at: http://www.worldspaceparty.com/tickets.phpLimited VIP tickets available. Privileges include: VIP room overlooking the main floor, open bar and food throughout the evening, a chance to meet silicon valley innovators and dynamic thinkers, exclusive Bay Area Yuri's Night memorabilia and much more to be announced. PLUS! Space Cadets are invited to go weightless and experience zero-gravity on Sunday, April 22, 2007! This unique VIP experience will provide you with a ZeroG flight flown from San Jose International Airport PLUS exclusive access to all Yuri's Night Bay Area 2007 events. 3-2-1 Liftoff! VIP Flight Tickets $5,000.00 each. Email zerogartists@mac.com to reserve your seat today. Don't let this zero gravity opportunity to fly float by! As always, please check www.worldspaceparty.com for the latest… Yuri's Night Bay Area Crew, Over and Out. End Transmission.++++++ Any special requirements for individuals with disabilities should be related to the event staff or security, and reasonable arrangements will promptly be made. An ADA/Handicap parking lot will be available and marked with signs. References to NASA Ames shall not be construed as official NASA approval or endorsement of any non-Governmental or commercial entity or activity.

Topic by lannanh 12 years ago


"Sonic" drilling or cutting

If we look up sonic drills today we usually get some fancy machines driving pipes in the ground, preferably softer ground.But the term includes all types of machines that use sonic vibrations to advance through a media.With the ancient and claimed to have never existed technologies in mind I did some digging...In the food industry vibrating knifes are quite common, same for "air knifes" on softer food.Even in the meat industry they find more and more uses now.Ultrasonic cutting or welding is the same thing and included in "sonic".Same for some experimental sub sonic drilling methods currently being tested.The general idea might be as old as using vibrating equippment to compact stuff, like concrete, bricks and so on.What you can compact by vibration you can also make "fluid" by vibration.Industrial feeder systems utilise this to the extreme by even making light and fine particles like flour move like water without causing any dusting.What all the techniques have in common that a suitable tool or tool head is used and that it is attempted to use the most suitable vibration frequency for the job.Anyone operating an ultrasonic welder knows the pain of finetuning for a new electrode or just new part to be welded.What does that tell us now that makes the understanding easier?Take a bottle of ketchup, preferably one that is still quite full.Turn it upside down and noothing comes out.Shake it a bit and you are either lucky or drowned in red.But hold it at an angle and start tapping it and the red sauce flows out easily.What it true for most newtonian fluids is in some way also true for non-newtonian fluids.Ever mixed corn starch and water to make these funny experiments with it?Hit it hard and it reacts really hard and is not sticky at all.Leave your hand resting on it and in sinks in and sticks to it.Stirring it very slowly is easy, go faster and you get stuck.You can do similar things with by using an external source for vibrations.For example a vibration speaker mounted to a smal cup of the goo.If you place sand on a sloped piece of plastic or sheet metal then at a low angle it will pile up easy and stay.Start vibrating the plate and the sand will start to flow off.Works fine with a vibration source mounted to a piece of steel bar or rod and a bucket of sand too.Trying to press it into the sand requires a lot of force, especially once you are a bit deeper.Let it vibrate properly and it slides rights down.If we can do the simple stuff as well as really complicated stuff in the industry then what about other materials?So far we use vibrations to make things move out of the way, compact things, transport them or to heat them up for welding plus some cutting applications.Considering the variety one might wonder why no one tries it for "difficult" materials.Machined surface can be found throughout ancient history.Finding "machined things" were vibrations was clearly used is a bit harder.The great walls are not a perfect example here as the views differ quite a bit on how they could have been created.But if we leave things melting them or a secret concret like recipe for creating for example granite then vibrations start to make some sense.You find some interesting videos on youtube where people use speakers, wires and rocks to confirm you can actually "machine" them by vibrations.Especially granite has some quite musical properties, big boulders as well as smaller ones produce destinct sounds when you hit them hard.Tests and measurements were made on granite and other hard rocks to check how fast sound travels in them , how it is refeclted and where the sound comes out or affects the surface the most.Lets just say every sample gave different results.Shape, density and dimensions affect not just the resonant frequency but also where and how the sound travels in the rock.What if??We can use a simple speaker, a plate and some rice to see how patterns form under various frequencies.Works with sand or other granules as well.The interesting patterns are the so called harmoncis.Here we see clear and destinct patters, sometimes with extremely fine lines and areas of softly vibrating granules.Some people say these harmonic frequencies have all special meanings and uses.We mainly used them to avoid problems.Imagine your new TV would not have a housing tested to be stable with all frequencies the speakers can produce.All of a sudden your back of the TV might start to rattle ;)Same for car engines.Harmonic vibrations are eliminated wherever possible.Otherwise they could multiply and affect other things in the engine or around it.Simply put it means we have various options to detect and measure vibrations on a surface or in a system.Back in the day every half decent backup generator had a mechanical indicator for the frequency of the supplied electricity.A set of tiny forks with the desired on painted red and several on either side of it.These forks were designed to get into harmonic and therfor quite intense vibrations at their set frequency.If the one for 50Hz looked blurry then all was good ;)The same principle god be applied on a big boulder of granite.Place the "vibration meter" at the desired spot and start moving around the vibration source on the surface until you find a spot that causes maximum response on the meter.Best thing here is that if you then place that surface area onto another peice of fixed in place granite both pieces will start to loose substance if vibrations are applied.The fine sediment forming is then usable as an indicator where to move the vibration source to continue once the effect literally wears off.Is it feasable?Well, if we trust mainstream science then the answer is no.A huge amount of vibration energy would be required for such a hard material, despite ancient proof that says otherwise.Semi industrial test also seemed to confirm the theory as only with very high amplitudes (loudness) and while automatically adjusting for the resonant frequency changes a measurable amount of material was removed.I struggle a bit with that as for the testing tool heads made from hardened steel or carbide were used.And that with little or no regards on how the head and tool itself affects the output.I mean in terms of having the max possible movement happening right t the tool contact surface!There is a huge difference between applying a vibration to a tool and using a system, tool and tool head DESIGNED to work at the desired frequency!Otherwise we wouldn't need a computer to design and test a horn for welding purposes or shade a knife spefically so that the vibration go along the right axis and in the right direction.You not break a hard thing with a very soft thing unless it travels fast enough to become harder as the target!This complicated explanation basically just confirms that if you hit water at a too high speed then it will just break you into pieces instead of offering a soft splashPlease do not jump of bridges or such to confirm this yourself!!If that is really true and science says it is, then how about the other way around?Works fine too, or we wouldn't have pressure washers or water cutters.Now for the part where I hope some really smart people leave helpful comments:If we can cut steel with just a stream of water, then I ask:Isn't for example copper much harder than water?Steel is much harder than copper but water cuts through it.The answer here it simple or complicated, depending on how you want to expain how it works.Comes down to speed and pressure plus the right nozzle shape to prevent a beam expansion.But then water is indeed "harder than steel".Questions:Lets say we would use a copper pipe that in lenght, thickness, hardness and diameter is optimised to transmit a frequency so the pipe end sees the max vibration like a feed horn for ultrasonic welding.Not to hard to calculate these days :)Now imagine said "main frequency" would be optimised for the pipe but also be a harmonic frequency of the rock to be worked on.The pipe end would deform quickly, abrasion does the rest and it fails before even making a decent sratch that is not copper metal on granite.No matter how hard we press nothing good enough will ever happen.BUT: If we would add more hormainc frequencies to feed our pipe we can multiply the amplitude quite easy!Just try with a sound generator from your app store, needs 2 or more channels to be usable.Pick for example 400hZ on one and 800Hz on another, then finetune around these number to hear how the tone changes ;)My theory goes like this:If all "working frequencies" would just harmonics of the resonant frequency of the granite, then they can be tuned so the effect on the pipe end is minimised.The overlaying frequencies however should result in the same effect a water cutter has: The pipe becomes ultra hard.The better the match and the more you have to get it right the harder the pipe will be.Adding now a "drilling frequency" or multiple could be used to drive these harmonics slightly out of phase.Like with the sound generator on your phone we end up with a pulsating sound, or vibration.While the pipe still vibrates at the same "hardening" mix the drilling frequency creates a peak like a jackhammer.Try it by using the heaphone output on a small speaker and placing some light and tiny things into the cone.The will violently jump around during these pulsing tones.For a drilling system the output can be mechanically maximised by utilising a pitchfork design.A head holds the vibration speakers and the tynes are tuned good enough to the frequency of the speakers.Always two would have to operate in sync though as otherwise the pitchfork movement that transfers the sound down the center bar won't work.This head could then be desgined to act as a holder for a quick change of work out pipes that are no longer long enough for tuning.I guesstimate that a well tuned design would result in a copper pipe being able to drill at least 10 to 15cm into solid granite before it wears off too much.And we are talking here about just a few mm to get the thing out of tune!But would dare to desing such a thing just to confirm a theory that no one ever really dared to test? ;)And if friction welding works as good as ultrasonic welding, then what would happen if we try this with the right frequencies and vibrations instead of wasting tons of energy?

Topic by Downunder35m 2 months ago