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Poor man's MIG Welder

K

kevinthenerd

Platinum Member
Using an old laptop power supply and a whole bunch of capacitors, I've been able to get a good start making a poor man's MIG welder. I started off using tin/lead electrical solder, but I'm moving up in power to be able to use antimony solder. (I hope to use regular MIG wire when I get enough capacitors.)

Does anyone have any ghetto ideas for the inert gas? I thought about mixing baking soda and vinegar in a 2-liter bottle and piping the CO2 to the tip. Any other suggestions?

Two main goals:

1. To be able to solder bicycle frame tubing.
2. To not spend more than $10 for the whole thing.
 
Solder is not strong enough for load bearing joints in most cases. You are not welding, you are soldering. What the heck are you trying to do?
 
for your "ghetto" inert gas part, i suggest a small 12-gram co2 cartridge used for paintball? they're cheap
 
Interesting. However, if you haven't welded before using this and making good welds should prove very difficult, considering this is not going to be extremely powerful
 
You are not welding. As ronstang says, any joints are going to be weaker than heck. Just take 2 car batteries, wire them in series, and use a pair of jumper cables to hold an arc-welding rod. You will have zero amperage control, but you will be abale to weld.
 
I can spot weld sheet metal with large caps 🙂 But, ya, solder isn't going to hold a frame very well. You need to try, depending on the material of the frame, aluminum or steel rods. When you can melt those then you are ready grasshopper!

 
Originally posted by: Evadman
You are not welding. As ronstang says, any joints are going to be weaker than heck. Just take 2 car batteries, wire them in series, and use a pair of jumper cables to hold an arc-welding rod. You will have zero amperage control, but you will be abale to weld.
Click to expand...

Throw in a rheostat from an old stove or an element heater and there's your amp control. 🙂


 
Originally posted by: Evadman
You are not welding. As ronstang says, any joints are going to be weaker than heck. Just take 2 car batteries, wire them in series, and use a pair of jumper cables to hold an arc-welding rod. You will have zero amperage control, but you will be abale to weld.
Click to expand...


Actually you can use an automobile alternator and a regulator to make a cheap welder. My buddies with 4X4 vehicles have built these....kind of cool. The add an extra alternator on the engine to be a welder and an extra air conditioning compressor to act as an air compressorto run air tools. They use the bumpers and roll cages as air storage. I helped one of them build and WELD a whole system like this. With my MIG WELDER!
 
Originally posted by: Xanis
for your "ghetto" inert gas part, i suggest a small 12-gram co2 cartridge used for paintball? they're cheap
Click to expand...

You need a good amount of CFM for shielding gas. IIRC, there is about 3 cubic feet of CO2 in a 12 gram carterage. That would give you about 15 seconds of shielding.

Also, don't skimp on a good face shield with at minimum a #10 shade. less than a minute of arc welding without a shade will destroy your vision.

Originally posted by: Ronstang
Actually you can use an automobile alternator and a regulator to make a cheap welder. My buddies with 4X4 vehicles have built these....kind of cool. The add an extra alternator on the engine to be a welder and an extra air conditioning compressor to act as an air compressorto run air tools. They use the bumpers and roll cages as air storage. I helped one of them build and WELD a whole system like this. With my MIG WELDER!
Click to expand...

I haven't seen one made from an alternator, but I have seen add on control boxes that adjust the voltage from 24 to 48 volts. 2 alternaotrs are a pretty good idea as at 12 volts you probably need a good 300 amps to weld, which would give about 150ish amps for welding, enough for 1/4' plate with a couple passes.

I also want to add a york compressor to my truck for onboard air. I was going to use one of the new 6 piston compressors that GM is using now, as the CFM would be insane, but they are only lubricated by the refrigerant. I found out that air would kill them in short order. Do you know of a good site for info on the York and mounting designs? I think the Yprk is the most popular, but I'm not sure, it's been a while since I was doing my research.

<edit>
oops, that was supposed to be an edit of my original post. my bad.
 
Originally posted by: Ronstang
Solder is not strong enough for load bearing joints in most cases. You are not welding, you are soldering. What the heck are you trying to do?
Click to expand...

I was testing it on low-melting-point metals, hoping to increase the specs for later use on high-strength materials.
 
Originally posted by: kevinthenerd
I started off using tin/lead electrical solder, but I'm moving up in power to be able to use antimony solder. (I hope to use regular MIG wire when I get enough capacitors.)
Click to expand...

I guess those who say "that's not welding" aren't realizing my slow progression to something worthwhile. Yes, it's not welding unless you melt the base material. Otherwise, it's solder. Solder, especially tin-lead electrical solder, is very weak. I know this. Anybody who has taken a solid mechanics course will be able to look this up in their tables instantly to figure out just how much a solder joint sucks for strength.
 
Originally posted by: kevinthenerd
Originally posted by: Ronstang
Solder is not strong enough for load bearing joints in most cases. You are not welding, you are soldering. What the heck are you trying to do?
Click to expand...

I was testing it on low-melting-point metals, hoping to increase the specs for later use on high-strength materials.
Click to expand...

You are not going to get enough amperage out of a laptop power supply to reliable weld mild steel. You might get it to stick together if it is thin enough (although I still have doubts on that) but it will not be strong. If you need a welder then rent one.
 
Originally posted by: Evadman
Originally posted by: Xanis
for your "ghetto" inert gas part, i suggest a small 12-gram co2 cartridge used for paintball? they're cheap
Click to expand...

You need a good amount of CFM for shielding gas. IIRC, there is about 3 cubic feet of CO2 in a 12 gram carterage. That would give you about 15 seconds of shielding.
Click to expand...

It all depends. If you get the gas outlet close enough to your work, you'll be fine with a lower rate of flow. Maybe I need to invent some kind of delivery system to get it very, very close. It all depends on your ambient air flow, too. You can't MIG weld in a very stiff breeze.
 
Originally posted by: Ronstang
Originally posted by: kevinthenerd
Originally posted by: Ronstang
Solder is not strong enough for load bearing joints in most cases. You are not welding, you are soldering. What the heck are you trying to do?
Click to expand...

I was testing it on low-melting-point metals, hoping to increase the specs for later use on high-strength materials.
Click to expand...

You are not going to get enough amperage out of a laptop power supply to reliable weld mild steel. You might get it to stick together if it is thin enough (although I still have doubts on that) but it will not be strong. If you need a welder then rent one.
Click to expand...

Welders that don't use capacitors draw their current when they need it: at the time of welding through a large transformer. This is the reason for the insane power requirements. With a capacitance welder, however, all it takes is some patience to wait for the charge to rebuild slowly, safely trickling through the power supply between welds, drawing the same amount of energy over a longer period of time (and therefore requiring less instantaneous power from the supply).
 
Originally posted by: ScottSwingleComputers
Originally posted by: kevinthenerd
Originally posted by: Ronstang
If you need a welder then rent one.
Click to expand...

I'm broke. Renting anything would blow my budget.
Click to expand...


LOL. Did you forget that you already replied to that last night?
Click to expand...

hehe... stuff happens. I'm sure I'm still averaging more content per post than the average Lifer on here.
 
Just go to ebay and buy a cheap arc welder. I got mine for under $65 delivered and it weld everything I need it to.

I did the car alternator welder too but the total parts costs started to elevate past the level of a cheap ebay welder so it was no longer worth the effort.
 
Originally posted by: Gillbot
Just go to ebay and buy a cheap arc welder. I got mine for under $65 delivered and it weld everything I need it to.

I did the car alternator welder too but the total parts costs started to elevate past the level of a cheap ebay welder so it was no longer worth the effort.
Click to expand...

$65 is still a lot for me. I can't afford my ramen noodles these days. I hate this end-of-the-semester financial crush. It happens every Christmas and every summer when I start running out of my financial aid refund money and have to rely on my crappy pay. In the summer I have to support myself for a couple of months without it, and in December I have to buy gifts for people.

Oh, I discovered something rather stupid today. I should put a resistor in series with the capacitor when I charge it so I don't get the insane current initially across the laptop power supply. Then, the charge is allowed to trickle in over a longer period of time.

Does anyone have any capacitors out of car audio systems they'd be willing to donate?

I'm going to put a high-resistance multimeter across the capacitors to watch them charge. Maybe instead of a charging resistor I'll use a lightbulb (or series of lightbulbs) as a "charging" indicator.
 
Dude, lol..

Ghetto is not always best, and without amperage you aren't going to be able to weld anything. It doesen't matter how many caps you have if your power supply can't keep them filled.

Just go to Harbor Freight and buy one of their cheap MIGs.
 
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