I couldn't get 30g kanthal to weld to 32g nickel worth a poo until I used two 4700 caps @ 24-27v. I didn't try anything in between, I was a little frustrated and just went with the big guns....oh, also was not using the touch the two wires together technique so that may make a difference also. But I would try some more capacitance and see.
- Status
I couldn't get 30g kanthal to weld to 32g nickel worth a poo until I used two 4700 caps @ 24-27v. I didn't try anything in between, I was a little frustrated and just went with the big guns....oh, also was not using the touch the two wires together technique so that may make a difference also. But I would try some more capacitance and see.
Sooo, if you didn't touch them together, then what method did you use to get it to work?
I have base with a piece of 12g solid wire in it and another lead with a piece of 12g solid wire ....I clamp the wires over the fixed post similar to the pic below and then touch the wires with free lead.
Personally, I would not add that resistor - the fuse is enough to protect it. The original designer though that it would limit the current being drawn. I would, however make sure that there is about a 2KΩ - 3kΩ resistor from the charge switch to the cap to limit the initial surge current drawn by the cap.
EDIT: I believe he wanted to make sure that the current drawn from the battery would not be too high to damage the battery. I would put a 1A fuse in it; the cap should not require a large amount of current.
Last edited:
You won't actually get a longer weld time, but you will get more charge from the cap. It should help. And you can always dial down the voltage if it is too much.
Not very much, but I would be careful if I had a pacemaker...
Seriously, you can touch the leads without receiving a shock.
However, I would not get my face close to it without some eye protection; there is molten metal here and it is always possible a piece could fly out into your eyes.
Last edited:
True. If you pull the resistor (or don't have one) also pull the diode since it will blow if the current is not limited. Then move the momentary switch to where the diode is on the schematic. I think this was your idea dsy, it is a good one too, I just didn't want to have to go back and start editing post and redrawing stuff
There is a little more flexibility in the design if you use the resistor but since most people are going to be using high drain batteries here, it should be of little concern.I didn't have any trouble welding those same wires together at 35v with 1000uf. Are you successful with other gauges?
Now that I am thinking back to it, the reason I put the switch before the lm board and used the diode instead of putting the switch on the output side before the cap was to help "hold" the voltage on the cap. If you do it like this, the caps on the lm board themselves are going to continue to put out a little juice after you let go of the switch, which in turn helps "hold" the full charge on the welding cap a little longer. In theory this makes a lot of since, in practice it is probably not needed since we are welding the wires pretty quickly after pushing the button, if you wait longer you can always tap da button again too
I had to wire mine without the resistor. I either had a bad resistor (doubtful) or I screwed up adjusting the LM board. Either way gsa guided me through the process of removing it.
+ from the battery attaches to the fuse then the fuse goes to the IN+ on the board.
The diode is removed and the switch replaces it. The switch goes from the + out from the lm board to the cap.
It works fine.
Steve
Well I shown my flash welder to my dad and he freaked out and said he wouldn't look at it and I shouldn't without eye protection because arcs are dangerous to the retina no matter the voltage. I knew arcs shouldn't be looked at but I didn't think this thing was powerful enough to cause serious damage, that's why I figured I would ask you guys because I can't find any info on the net about low voltage arcs and eye protection.
I needed to get some more resistance wire and mre777 turned me on to this ebay seller so I stocked up
Added a second 50v/1000uF cap and was successful welding the nickel to kanthal at 35 volts.
To all those successful welders out there....how stong is the weld? Kind of a relative question I know....but how delicate do you have to wrap coils to avoide breaking a wire or pulling apart the weld?
Don't know yet, welded for 5 coils, will roll 5 oval coils tomorrow and get back on that. Hope they hold. I will try not to put much force on the weld.
An industrial arc welder, yes, eye protection is a must - the flash produced is like looking at a lightning bolt 50 ft away from you. This wire welder doesn't produce anything near that as an arc; a $2.00 flashlight is brighter than what it can produce. IMO, and this is not a fact, there is not a risk of retinal damage. There is, as stated before, the chance for molten bits of material to be emitted.
The risk of retinal damage is due to the intense light produced by an arc...
Of my 10 welds 4 came apart as I rolled my oval coils. No problem welding them back after the coils were formed, In fact may do it that way in the future. I think my problem is getting a good contact when I bring the wires together, hit or miss doesn't do it. Need some kind of mold that will steer the two wires together for a good contact.
Hey me too
dsy5 will probably comment as he will likely try it before me....He had the thought to try using a good old knife switch to release the capacitor charge. This way the wires can be positioned touching and then quickly throw the knife switch to make the weld. dsy5 was able to achieve a similar result using a banana connector.
Does "knife switch" instantly bring images of Frankenstein to anybody else
Last edited:
- Status
Similar threads
