Spot Welder Help
 

I will be replacing some panels in a "not of this forum" vehicle and I suspect one or two folks here have experience with single side spot welders. I have an old spot welder similar to a Marquis Redi-Spot. It uses a gun very much like this one:

https://www.anyandallauctions.com/It...009002_lg.jpeg

I would like to select the most appropriate rod to try with this welder. I cannot find a manual for this tool but it used to use special "copper coated" welding rods. I have found an article for a "DIY Spot Weld Gun" which noted the large copper outside ring on the gun acts as a heat sink so standard arc welding rod works fine. I have found posts on welding threads where folks say this welder should use "carbon-arc" rods. Carbon-arc welding by the looks is essentially creating an electric torch to weld with. Maybe not the best for spot welding? Finally, I can find copper allow rods designed for pressure spot welding. These rods pass current through the parts being welded to "resistance weld" the panels at the weld point. Unlike the other two solutions, this method does not arc weld the panels. It spot welds.

So... anyone have experience with this or have suggestions about what rod is best?

Thanks

Re: Spot Welder Help
 

the rod you're looking for is carbon arc rod. available at any welding supply house.
you can weld, gouge and cut with them, using a stick welding lead strike an arc and pull back, feed filler rod in other hand
i learned to braze galvanized duct together with silicon dioxide rods, similar to gas welding
uses arc welder power source on reverse polarity

i'll assume the trigger pulls the rod back. place gun against metal, pull trigger to pull back on rod, acquire arc, then move in to cool arc and form puddle. done

you can do the same with arc welder, strike an arc and start melting

https://www.zoro.com/static/cms/prod...wE_0pcpEx_.JPG

i don't recommend using carbon arc rod, fell out of use when wire and mig welding came in to play
wire welding was/is mostly used for basic automated welding. axle tube flanges, spring pads, shock brackets are wire welded

Re: Spot Welder Help
 

I've got little Montgomery wards 110 V 1 power setting welder out in the shed that was designed for carbon arc or used some special and rather expensive at the time welding rods. I used it to tack things together in Texas so I could take them down the street to my friend to have him weld them.

I rather agree that that style of spot welder might be obsolete technology. I'd play with it on scrap metal before attempting to weld on the truck.