That's pretty slick.
How to: Make a Trail Mig (Flux Core) welder
Hi all. I just finished making a mig welder that uses 2 car batteries (24v). Here is the how to. Total cost was around 150, but only cost me around 50 as I consider the welder free. This is basically the same system as ready welder but without the cost.
My cost was $35 dollars as I had many of the "parts" lying around.
Parts List:
1. Harbor freight 90 amp Flux core welder. This was my first welder, but it had outlived its usefulness as I got a better machine. Frequently on sale for $90
2. PWM (Pulse Width Modulation) 24v motor speed control ($25) - ebay
3. Jumper Cables ($15) - 8 ga seems to not get hot at all.
4. Plastic Home Depot tool Box ($8)
5. Battery Disconnect Switch ($4)
Step 1. Take out the "guts" from the harbor freight welder. The only parts you want are the ground cable, Torch cable, Wire feed motor assembly and the thing that holds the spool of wire. I don’t have a picture of the gutted welder.
Step 2. Take out the Top plate in the welder that all of the above items and attach into a box of your liking. I used a 8 dollar home depot tool box as seen in Pic 5 below. I cut out the handle part and screwed the metal plate from the mig welder into it to hold all of the items.
Step 3. Install Battery cutoff switch in appropriate position (red handle thing in Picture 5. This allows me to turn off and on the welder without needing to mess with the jumper cables.
Step 4. Wire up the Motor to the PWM speed control and trigger switch on mig gun. Picture 1 and 2 for the Wiring diagram
Step 5. Attach the welding "ground" to the Positive Connection on the battery, Attach the mig gun to the negative battery connection. via the jumper cables
Step 6. Tidy up the wiring (which I have not done yet), attach the PWM Controller somewhere Fit it all in a box and turn the speed control to about 20 % and run a test bead (Picture 4) The picture shows .030 wire, I have since tested .035 and liked the results even better, but either work ok.
Step 7. Put you goggles, Gloves and all the appropriate cables (I put my 4 1/2 grinder) in the tool box for your "welding kit" It all fit in nicely.
Optional: I thought about just putting terminals to hook normal jumper cables to, but I really did not like the idea of having to pull the welder around and have a cable short out somehow. I opted for the dedicated cables, but it would be easy to do some type of high current connectors I suppose. This would take away some of the bulky wiring. I would also consider a better ground clamp. The one from Harbor freight gets very hot, but the harbor freight mig gun does not seem to heat up.
Please post back if you have tried this and liked it.
Your Done, and saved many $$$ over a ready welder. Any Questions or comments?
My cost was $35 dollars as I had many of the "parts" lying around.
Parts List:
1. Harbor freight 90 amp Flux core welder. This was my first welder, but it had outlived its usefulness as I got a better machine. Frequently on sale for $90
2. PWM (Pulse Width Modulation) 24v motor speed control ($25) - ebay
3. Jumper Cables ($15) - 8 ga seems to not get hot at all.
4. Plastic Home Depot tool Box ($8)
5. Battery Disconnect Switch ($4)
Step 1. Take out the "guts" from the harbor freight welder. The only parts you want are the ground cable, Torch cable, Wire feed motor assembly and the thing that holds the spool of wire. I don’t have a picture of the gutted welder.
Step 2. Take out the Top plate in the welder that all of the above items and attach into a box of your liking. I used a 8 dollar home depot tool box as seen in Pic 5 below. I cut out the handle part and screwed the metal plate from the mig welder into it to hold all of the items.
Step 3. Install Battery cutoff switch in appropriate position (red handle thing in Picture 5. This allows me to turn off and on the welder without needing to mess with the jumper cables.
Step 4. Wire up the Motor to the PWM speed control and trigger switch on mig gun. Picture 1 and 2 for the Wiring diagram
Step 5. Attach the welding "ground" to the Positive Connection on the battery, Attach the mig gun to the negative battery connection. via the jumper cables
Step 6. Tidy up the wiring (which I have not done yet), attach the PWM Controller somewhere Fit it all in a box and turn the speed control to about 20 % and run a test bead (Picture 4) The picture shows .030 wire, I have since tested .035 and liked the results even better, but either work ok.
Step 7. Put you goggles, Gloves and all the appropriate cables (I put my 4 1/2 grinder) in the tool box for your "welding kit" It all fit in nicely.
Optional: I thought about just putting terminals to hook normal jumper cables to, but I really did not like the idea of having to pull the welder around and have a cable short out somehow. I opted for the dedicated cables, but it would be easy to do some type of high current connectors I suppose. This would take away some of the bulky wiring. I would also consider a better ground clamp. The one from Harbor freight gets very hot, but the harbor freight mig gun does not seem to heat up.
Please post back if you have tried this and liked it.
Your Done, and saved many $$$ over a ready welder. Any Questions or comments?
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1 - 20 of 45 Posts
That is a great creative design but I am concerned that it won't put out enough heat for many common trail heavier gauge steel repair jobs.
Using a 90 amp MIG welder for 3/16" is marginal under most conditions, and lots of stuff that can break on the trail is at least 3/16". How well does that work for you with 3/16", especially when that 3/16" is a large piece or part of something bigger that will sink off a lot of its heat?
Cable-wise, I plan to use at least 4 gauge jumpers for mine, 8 gauge is pretty small stuff for jumping batteries and welding.
I like your idea and I am tempted to make one but I am concerned about its 90 amp rating.
Using a 90 amp MIG welder for 3/16" is marginal under most conditions, and lots of stuff that can break on the trail is at least 3/16". How well does that work for you with 3/16", especially when that 3/16" is a large piece or part of something bigger that will sink off a lot of its heat?
Cable-wise, I plan to use at least 4 gauge jumpers for mine, 8 gauge is pretty small stuff for jumping batteries and welding.
I like your idea and I am tempted to make one but I am concerned about its 90 amp rating.
Yes but as described above, the welder is no longer limited to 90 amps as it was when it came from the HF factory. I'm looking for a used HF 90 amp welder (I made a $40 offer yesterday for a used one that was refused) for this project but I'll be using 4 gauge cables for it.
OK a few extra pictures.
As promised, the diagram on how to make it a "cold tip" welder. Here I utilize a 24v starter relay. It should have enough current capacity. I have not tested this configuration, but I am confident it will work. The most important factor is to get a starter relay that is sized appropriately to handle the current.
I learned to weld with the hot tip, so even on my cold tip welder I really do not miss that feature. My mind is now hard wired on how to use the hot tip.
Also another picture of the welds, this time wirebrushed so you can see a little better. Did not need the welder on the 33 mile Dusy trail this weekend. I was hoping to need to help Someone else out, but I was totally happy not breaking anything.
As promised, the diagram on how to make it a "cold tip" welder. Here I utilize a 24v starter relay. It should have enough current capacity. I have not tested this configuration, but I am confident it will work. The most important factor is to get a starter relay that is sized appropriately to handle the current.
I learned to weld with the hot tip, so even on my cold tip welder I really do not miss that feature. My mind is now hard wired on how to use the hot tip.
Also another picture of the welds, this time wirebrushed so you can see a little better. Did not need the welder on the 33 mile Dusy trail this weekend. I was hoping to need to help Someone else out, but I was totally happy not breaking anything.
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Muddy93
I just thought about what you were trying to get at with basically having the tool box be the welder and then have a DIFFERENT box that held the transformer. and when you wanted to weld you hook up to the transformer at home and the batteries when out on the trail.
With the addition of a rectifier you can eliminate the stock wire speed controller and use the PWM controller exclusively. (see attached diagram)
The only thing I am not sure about is how large of a capacitor. I am not enough of a EE to help with that. I would just put in a big one and see if it works. (like 1000mf) Many rectifiers are rated for 10 amps or so so this is not an issue. The capicator is there for filtering of the incoming power to generate a more smooth DC current. The rectifier can take either an AC or DC input. The welder will output a AC arc when on AC power and a DC arc when on DC power
When you are at home, hook jumper cables to transformer leads The polarity does not matter. When on the trail hook to the 2 batteries (Polarity matters). It all works the same.
I just thought about what you were trying to get at with basically having the tool box be the welder and then have a DIFFERENT box that held the transformer. and when you wanted to weld you hook up to the transformer at home and the batteries when out on the trail.
With the addition of a rectifier you can eliminate the stock wire speed controller and use the PWM controller exclusively. (see attached diagram)
The only thing I am not sure about is how large of a capacitor. I am not enough of a EE to help with that. I would just put in a big one and see if it works. (like 1000mf) Many rectifiers are rated for 10 amps or so so this is not an issue. The capicator is there for filtering of the incoming power to generate a more smooth DC current. The rectifier can take either an AC or DC input. The welder will output a AC arc when on AC power and a DC arc when on DC power
When you are at home, hook jumper cables to transformer leads The polarity does not matter. When on the trail hook to the 2 batteries (Polarity matters). It all works the same.
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1 - 20 of 45 Posts
