Resistance-No Resistance wire welder

[bapgood]

Ok I got all the stuff. Now what?

With a bowling ball and a slide

 

[mre777]

Ok I got all the stuff. Now what?

I love how the electric fly swatter is still up in the mix

 

[TBinAZ]

I was wondering what that black flashlight looking thing is. Thought it was an upcoming personal defence device.

I love how the electric fly swatter is still up in the mix

 

[bapgood]

Used the LM2577 output voltage for the supply voltage and used one of the other outputs to feed the feed the cap. It doesn't get much more stable than this.

Dsy5 warned me about using the output to stabilize the discharge since it is basically a short to ground when making the weld, and the documentation agrees "Note 5: Short circuits from the output to V+ can cause excessive heating and eventual destruction. When considering short circuits to ground, the maximum output current is approximately 20 mA independent of the magnitude of V+."

So since the drain to the cap is so minimal without it, I'm not going to use the second output to the cap.

The threshold voltage needs to be at least 1v or more, less than the input voltage. So I will just set it up that way.

I might use a second output with a lower threshold with an amber LED to show charge and the red LED threshold at ~1v lower than the input. That way I know if it is charged but more than 1v less than the LM2577 so I can just recharge the cap via the charge button.

Now I just need to round up a bowling ball, slide, and some dominoes

 

[xMackx]

Here is a circuit diagram of how a camera flash circuit works. (for newbs like myself)

HowStuffWorks "How Camera Flashes Work"

 

[bapgood]

Ok you electrical guys....any reason a power mosfet cant be used to release the cap charge?

Shooters ready

I'm thinking (yes I know I should stop)....
- power supply (LM...ect)
- generous amount of capacitance (couple of 4700uF caps)
- power mosfet
- 555 timer

Build up a relatively simple circuit with a pot to the 555 timer to very the weld duration or gate signal to fet...giving you voltage and weld length adjustment.

Yes overly simplified.

 

[gsa]

As promised: Small Welder for joining Nichrome and Nickel Wires

 

[comptechltd]

As promised: Small Welder for joining Nichrome and Nickel Wires

gsa,

You are the MAN!!!!!!!! Many thanks

Do you see any issue with using banana clips to connect the 2 leads so they are removeable??

Steve

 

[gsa]

gsa,

You are the MAN!!!!!!!! Many thanks

Do you see any issue with using banana clips to connect the 2 leads so they are removeable??

Steve

No issue with that, you can use the screw post method or similar type deal and just put some wire leads on the back side to solder to the cap. That's how I did my first one.

 

[comptechltd]

No issue with that, you can use the screw post method or similar type deal and just put some wire leads on the back side to solder to the cap. That's how I did my first one.

Thanks, I'm seriously thinking of having the hot (+) lead use solid maybe 14 or 16 gauge wire. Pop it in the post and it will stay where you put it. Make the other lead flexible and then it helps steady the whole thing. The hot rigid wire holds one end then just tap it with the other.

Steve

 

[gdeal]

gsa,

You are the MAN!!!!!!!! Many thanks


Steve

+1 on that comptechltd

 

[Koman]

As promised: Small Welder for joining Nichrome and Nickel Wires

Thanks man. Good stuff!

 

[breaktru]

VTTV

 

[mre777]

VTTV

Yea! He said my name "Look mom Im on TV! Well kinda" Thanks for the citation breaktru, I appreciate it.

 

[bapgood]

I thought this was interesting and worth sharing...

 

[breaktru]

Does that also apply to McNuggets?

 

[bapgood]

Does that also apply to McNuggets?

If so I must be a positive electrode

 

[gdeal]

I dont want to bust anybody's McNuggets, but how do you experts interpret that?

It states that lower resistance (ie. silver wire) be on the positive side, but that the thicker (higher melt point - ie. Kanthal) material should be on the positive side as well.

 

[bapgood]

It states that lower resistance (ie. silver wire) be on the positive side, but that the thicker (higher melt point - ie. Kanthal) material should be on the positive side as well.

You nailed it .....Just use thicker silver....jk

I just thought it was interesting info and that people may want to try experimenting and see if it makes any difference in our application.

 

[xMackx]

Stopped by walgreens and picked up 2 Fujifilm disposables, I got the outer shell apart. I pulled out the flash circuit and to make sure the cap wouldn't zap me I touch my pocket knife to both leads on the cap and the spark scared the crap out of me. lol