DIY On-board Welder


New member
I recently got back from an overland trip where someone had installed an on-board welder to their Mercedes bus. The set up came in handy several times throughout the trip for welding back a broken hitch, an A-frame for towing, fixing a broken roof rack, etc.. I have been looking around and can't seem to find any on-board welder instructions that I trust. Does anyone have any pictures, plans, or advice that they would be willing to share?


Enfant Terrible
Just south of where I live is a fellow who installs these units. I know it is a kit and not quite a DIY but it was awesome to see in action on a back country run. He used the mig setup and had a half sized bottle of gas since I think he knew what type of work there would be (a pole fence).
Here's the link if this is what you are asking for. If not, sorry.


New member
Thanks Semi-Hex, I found what I was looking for. I'm trying to avoid paying the $1000 to have an welder in my car if I am only going to use it in case of emergencies. It seems a lot of people use 2 or 3 batteries connected in series with jumper cables and a welding stick. I'll try this out this weekend, but I'm really looking to install a "weldernator" which requires installing an additional alternator in my car. I think this is by far the best option due to the fact that I would always have a backup alternator with me on overland trips.

Happy Joe

Apprentice Geezer
My experience;
2 good starting batteries in series work fine; 3 good starting batteries in series is enough to blow holes in 3/16" plate.
Use heavy duty jumper cables (should carry these any how) and a decent rod holder/stinger on a separate piece of welding cable (jumper cable clamps do not want to hold the rod well).
The jumper cable clamps can melt their way into the battery terminals.
A cautionary note; lead acid batteries can emit hydrogen gas under high discharge or charge rates (danger of battery explosion; although so far it hasn't happened to me).
I favor a #10 welding lens in a pair of cutting goggles.
Get a chipping hammer. A cheap inverter powered angle grinder would not be out of place.
A section of 1 1/2" or 2" PVC pipe works fine to store the rod (rubber caps are easier to remove).
Most of my battery welding is done with 1/8" 6010 or 6011 rod; but 5/32" 6022 deck rod (recommended for flat horizontal use only but works for me everywhere) works about the best for me (normally available, locally, only in 50 pound boxes).
When the rod catches fire reverse the polarity.
When the rod sticks, check the connections and/or recharge the batteries.

I thought about setting up a spare alternator under the hood for welding and winching (and 110 volt, NOT 60 cycle) power) but since it is rare that I do/need any of the above, it hasn't been worth the trouble, for me.



you do realize that you're toasting the batteries if you're drawing that much power from them.
Unless that weld is a life-or-death situation i'd save it until you hit pavement and find a shop.

that being said, i think the alternator welder is the best option. you dont want to weld up your piece and then find that you dont have enough juice to start your rig up.


Yes , and if you leave your dome light on long enough, that will toast your battery. Obviously you cannot weld indefinitely off your battery. But by spreading the load across 2 or 3 batteries , you can safely get a decent amount of trigger time .

For reference, we had about 3 or 4 minutes of trigger time each repair with no I'll effects on our ability to start our trucks....

Happy Joe

Apprentice Geezer
The reason you carry a welder (besides for your friends) is to allow you to repair the vehicle so that you can get somewhere there is at least cell phone reception. It should be a permanent repair and get you home safely. If you are a good welder; no further attention should be necessary (maybe paint).

Done a lot of battery welding off road over the years; batteries killed = 0.
Batteries killed by winching = 3 (before fuel injection and before the vehicle was properly set up).

As mentioned when the rod begins to stick its time to recharge the batteries (with plenty left to start the vehicle), never tried to measure the level of discharge when this happens but since my average used (junkyard) battery lasts about 8 years including infrequent welding and rare winching duty; I don't see it as a battery killer.
Marginal batteries require more frequent charging, or may not work.

... general info...MIG technically needs an inert gas (Metal Inert Gas).
A spool gun with flux core wire (minus the gas) works well too, although they appear a bit more fragile than a stinger... use what works best for you...

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I gotz dis
Cheapest setup is stick welder kit. Picked this up from Barnes Welding here in Sacramento area. Less than $200.

I added battery clamps to make it easier to attach in lieu of vice grips.

Need 2 batteries to get yourself safely home.

Haven't had a need to use, yet.



New member
Nice, something that cheap is really what I'm looking for. What comes in the kit? Does it work off the battery?
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Supporting Sponsor: Cruiser Outfitters
I'm a big fan of ReadyWelder's, they've save the day on more than one of my trips and I generally have one stashed in the vehicle on any long trip. Like many tools it's certainly not something I would recommend everyone carry (such as a tow strap or jack) BUT for a big group that travels together often, invest in one or see if one gent will pony up. Plug for our rental program:

We've had many groups rent them to have along for their "big trip" be it Rubicon, Central America, etc.

Happy Joe

Apprentice Geezer
A Note for beginning welders and those thinking about it...
A welding shield for your eyes is a must to prevent serious, permanent, eye damage (retina burns) people vary, but I use a #10 lens in a par of cutting goggles when portable welding.
Cutting goggles are not recommended because they do not filter the light well enough and they do not provide overall face protection from the U-V allowing potentially extreme sunburn and, potentially, skin cancer long term.
I use cutting goggles only to hold the welding lens and only because they pack much more compactly, allowing me to carry and occasionallyuse a potentially trip saving item (the welder).



Rock Stacker
The readywelder is easy to use. stick is an old school art, wire is much easier for a beginner to get good welds. I have welded 3/4" plate in one pass with mine, done some .120" tube too. It is pretty durable and uses standard Tweco front end parts. I bought mine off of craigslist for $250, it still had demo spool in it. it is the "always hot" version but works fine. I added a 10' extension using anderson connectors plus a jacket, thin tig style gloves, a auto dark goggle, face mask, spare parts and arm guards in the same case, fits behind my spare tire.

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