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Step 1: You Might Be Surprised How Cheap It Can Be
Have you seen the video above? If not, take a look now because it will help you as you go along in this instructable.
A typical resistance Spot-Welder can range in price from about $200-$800, but with a little resourcefulness, and a bit of free time, you can make one like this for about $10 or less.
Spot welders are used to fuse thin sheets of metal together. They are most likely used in the auto industry, as well as HVAC for welding metal ducting.
There are a couple of videos you should see before starting on this project, because you may want some background on how the device works.
Here is how to: Make The Metal Melter
Here is what it can do: The Metal Melter
A typical resistance Spot-Welder can range in price from about $200-$800, but with a little resourcefulness, and a bit of free time, you can make one like this for about $10 or less.
Spot welders are used to fuse thin sheets of metal together. They are most likely used in the auto industry, as well as HVAC for welding metal ducting.
There are a couple of videos you should see before starting on this project, because you may want some background on how the device works.
Here is how to: Make The Metal Melter
Here is what it can do: The Metal Melter
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Where i live the voltage of a power outlet is 220v does this change anything?
Also is it possible to make one that welds two separate spots at once with the same transformer.
Best Regards
It may help to press the contacts together harder when welding. You may also need more power. (Eg. Bigger transformer)
--
Sam Wolff KK4NVJ
Best of luck,
Sam
--
Sam Wolff
KK4NVJ
If you use the transformer in short bursts of 10 seconds or less, you should be able to use it indefinitely. Allow time to cool in-between. You'll be able to tell the wires are starting to melt because they will be smoking. So stop when you see smoke (or before) and it should last forever.
Do you remember what hardware store? I went to Home Depot and could not find it.
I hope that helps!
I'm seriously thinking on making one of this.
thanks for the project,
I watched your videos a few times and got straight to work.
a few things to mention as help to others....
1) use the round holes in the corners of the laminate core to keep the laminates together when dismanling the core. a 6mm threaded rod and 2 bolts does the trick .
2) if you weld up the core when its wound and back together, shield the primary from the welding sparks.
3) one of your followers asked about the secondary coils size, non imp size is 16mm.
excellent project, i made mine in no time flat, i will be using it for every bit of tinkering I do in the future, (always soldered everything)
Thank you thank you thank you
when i deconstructed the core, the laminates came unstuck so i used the threaded rod through the alignment holes in the corners to keep the whole lot together. so when it came to construction i had everything square. Clamped the whole lot in the bench vice and used my ac arc welder. Its an old brute and i cant get the amps low enough so using a 2mm rod burnt the core a bit. rather went for a 3mm which lowered the amps. i merely welded along the grinding wheel lines.
the spot welder, (or metal melter as it is now coz i got too inquisitive before finishing the welder) works great.
PS, on the subject of the old oil bath ac welder.
i want to start a bit of TIG welding and wondered if this would work....can i use a diode bridge rectifier to convert my ac arc welder into a dc welder and create a tig set up?????
here's where i saw it, http://www.weldingtipsandtricks.com/homemade-tig-welder.html can you shed any light on it for me?
thanks once again.
I'm curious to know what you mean by the oil bath ac welder? I've actually been thinking about putting a transformer in an oil bath to help with the duty cycle on my stick welder.
Are there actually ac welders that do that?
Thanks for the updates on doing your weld on the transformer core. I'll have to give that a try.
As for rectifying the current, of course you can rectify the current, as long as you find diodes rated for that amount of current and heat sinks to help dissipate all the heat generated.
Thanks again for your feedback, comments, and best of luck!
Jip the old oil bath welders use transformer oil to cool the windings.
I say old but they are still available (and produced in the thousands)
They are rather heavy so are mainly used at small factories or home. I just find that the welding current can't be set low enough for thin material.
DC inverters have taken over, being light and portable.
I notice on the video (welding tips and tricks) that the heat sinks are large aluminium channels that the diode bridge is built on. this should dissipate the heat accordingly, I would just use a lot more vanes when i build one.
another thing to think about (hint hint hint) is a way to reduce the welding amperage, so when using the TIG set up, i can weld very thin material.
I'm about to start building a chopper that has no transmission, or chain, belt or shaft drive...... so will be fabricating gas tanks, oil accumulators, etc. and need low amps for that. watch this space....
Just want to thank you again, magic talking to like-minded inventors.
I enjoy your comments. I don't have much experience welding personally, so I pick up ideas from your suggestions :)
I spoke to a few people about the bridge rectifier, heat sink and reducing the amperage. seems like the solution is a potentiometer, (or POT as its referred to) this will allow us to reduce or increase the amps on demand for each job.
I'll check it out and tell you.
keep inventing....... its a human thing!
Keep on keeping on.....
the whole thing gets a bit hot, will air cooling with a fan help?
i've just two questions :
which kind of cable section do you use for the new secondary ?
Is this the same kind of cable section for the secondary with a primary of a french transformer in 230V ac ?
I have a 25mm2 cable.
thanks a lot.
i've just two questions :
which kind of cable section do you use for the new secondary ?
Is this the same kind of cable section for the secondary with a primary of a french transformer in 230V ac ?
I have a 25mm2 cable.
thanks a lot.
A hand held torch holds 2 carbon rods, about 2" apart at the torch and angled so that the rod tips just about touch. The torch also has a air nozzle in it hooked to an air compressor. The rods are +/- so the arc is between the rods and not between the rods and the work piece. You touch the work piece with both rods just to complete the circuit and get the arc started. Hold the rod tips and arc close to the work piece. When a molten puddle forms pull the trigger to give it a shot of air , this will blow the molten metal out of the way. Once started you can keep cutting, like with a oxy/ acct. torch. As the rods burn away you need to loosen the thumb screws that hold the rods in place and move the rods to close the gap back to the starting point. A good operator could remove the weld with little or no damage to the parts being separated. It's loud and very dirty also as I remember.
Thank You,
Gordy
LOL
Apart from an alternative choice of materials used (wood), one thing that I would add to your project is a fuse for your mains in.
This will give you and your home some protection against an electrical fault and may prevent an electrical fire.
Definately an ideas man!
Greetings from Belgium
Erik
Interesting project and really useful. I am wondering if you wound the transformer yourself or if it is an existing unit? I'd like to know what the voltage and current are for each half (that is, I understand the primary is 120V AC house current) but it isn't clear what the secondary is doing. If it's an 800 A. secondary current, that implies that the voltage is quite low and the number of turns on the secondary small and using large gauge wire as well.
As the standard 20A., 120V AC circuit (outlet) is restricted to about 13A (about 1600W) of power for safety reasons, that would imply that in order to have 800A available at the electrodes on the welder side the secondary needs to be about 2 Volts. (The power at each side of the transformer must be the same because you can't get something for nothing, don'tchaknow).
Please understand I am not taking issue with you about any of this...I am a consulting engineer in the radio business, and I just have this penchant for understanding the nature of the beast. I also restore old airplanes and a spot welder would be really useful in that respect!
Anyway, it's a really cool project and I plan to build one!
Thanks a lot!
---Michael
I was trying to get a spot welder to perhaps rebuild my 18v power tool battery packs.
Thanks for such a great instructable.
Many thanks
Theo
Gordy
Gordy
Calling it anything else makes you sound silly.
I'm sorry, but you don't get to rename electronic components just because you thing it sounds cool.
Apparently this is a real concern for you, and I'm sorry you're finding a way to be offended by my article, when none was intended.
Furthermore, if you do want to explore outside your own field, you don't just *make up* terms for things that already have names, you *ask* what the things are called. That's how you learn.
Sure doesn't sound like he's referring to a whole apparatus, rather then just the transformer.
You can get a whole variety of tungsten types:
Thoriated - Which is indeed mildly radioactive
Lanthanated - Non-radioactive, probably not too healthy.
Ceriated - Same as Lanthanated.
Zirconiated - Ditto
Pure Tungsten - Probably the best option here.
Realistically, you really don't want to use tungsten electrodes, as their resistance will be significantly more then similarly sized copper electrodes. If you look into production spot-welders, they all use copper electrodes, and just cool the tips to prevent damage.