Make a Cheap Spot Welder




Introduction: Make a Cheap Spot Welder

How to diy a cheap spot welder

Step 1: We Will Remove Secondary Coils With a Hacksaw

Part list:

01. 12V Relay Module External Trigger Delay Switch Time Adjustable

02. Button Switch

03. 0.15x8mm Nickel Plated Steel Sheet Strap Tape Strip For Battery Spot Welding

Step 2: We Will Add a Second Coil

I use the 70mm cable from old generator you can use other types welding cable. I recommend using a 35mm or more cable

Step 3: Box

I use old ATX psu for the box

Step 4: Timer - Switch - Welding Needle

01. Timer

You try to use other types but there is a note that you should select the timer can set the value is 0.1s. Because if your transformer is of great value long time can burn nickel.

02. Switch

I use a foot pedal from old motor bike. You can use a button as step 1.

03. Welding Needle

I use a needle of electrical soldering iron gun. There are many options for you

Step 5: Modular Design

I designed the module to avoid the wires.

Thanks for watching my friends. See you on next project

You can support me by watching the clip on Youtube.

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    10 Discussions


    Question 1 year ago

    You said "70mm cable from old generator".

    70 mm is a width just a little less than 3 inches.

    Isn't it 0.7 mm?


    Answer 5 months ago

    I am pretty sure he is mixing up the unit of measure for the WIRE GAUGE (the diameter of the copper core inside the yellow and green insulation material), which in his case looks like it could be about 7 millimeter or 0.7 centimeter.

    What (I think) he says right after that, is that this same diameter (of the copper core), has to be between 3.5 and 7.0 millimeters, again mixing up centimeters (cm) with millimeters (mm).

    I can't find anything regarding the length of the replaced secondary winding in the entire text, but from the looks of it, i'd say he used either a 70 centimeter, or 0.7 meter (m) long piece of cable, or exactly one meter of it (100cm).

    This instructable simply lacks very vital information, making it a very dangerous and potentially lethal set of instructions.

    Talking about vital;

    Putting a High Tension (Volts) and High Current (Ampère) Microwave Oven Transformer (or M.O.T) with a non standard, replaced secondary winding with a gauge difference so large, that it turns 230V(AC) @ 50Hz, into 2V(AC) @ 50 Hertz and somewhere around 40-something Ampère, is literally playing with people's lives.

    At the very least, the author should mention the dangers of mains power outlets, and describe what the process of replacing a winding on any transformer, does to the electricity flowing through it, or what goes in and what comes out before, and after the modifications.
    Also, when working with mains power one has to make it a custom to wear well insulated shoes and other gear, and remember the two most important rules for if you absolutely have no choice but to do this yourself instead of getting a certified professional or someone with a lifetime of experience as an amateur or hobbyist to do it for you;

    1) When working with HV/HT/HC power, always put one hand in your pocket or put your other arm behind your back, like an ice-skater.

    2) When you have to touch anything close to live wires or components under high current / tension, always use the back of your hand!
    At currents above 100mA (I think it is, verify this first!) your brains signals to your limbs and fingers are literally jammed or overpowered by the amount of current from the power source, when touching a live wire with the inside of your hand, you will NOT be able to let go of the wire, and that's when it's time for someone to call 911, 999, 112, etc.....

    That's just my 'two Cents' worth of information. Perhaps it will save one idiot from doing him/her/itself in.

    Uhm...Have a nice day?




    1 year ago

    A pedal is a lever or mechanism operated with the foot, you don't need to say "foot pedal", there isn't such a thing as a "hand pedal".


    Reply 1 year ago

    Thank you so much. My friend


    Question 2 years ago on Step 5

    What are you using for a power supply?


    Answer 2 years ago

    This timer use 12v DC and transformer use 220v AC my friend


    Tip 2 years ago

    Instead of using another connector for 12V, you could add a power supply inside and connect it to mains.


    Reply 2 years ago

    Thanks my friend because i can use a 12v adapter for more project


    2 years ago

    Yes my friend. You can see on clip 4:55 my finger touch the cos