spot weld gun

admin

Eastwood makes a spot weld gun (Part #19089) for an ac or dc welder that connects to a stick welder by attaching the positive cable to the gun and the welder ground to the object being welded using up to 60 ampsThis looks like an inexpierenced welder and hobbyist dream machine for replacing floor and panels in classic cars.Has anyone any any experience. comments or criticism of these units?It appears that you could use a cheap 110 volt welder and this gun - no learning, no warpage & low cost.Appreciate any advice or comments?Are other manufacturers making this gun?Thanks - Tom
Reply:Tom,Firstly, I don't know anything about the Eastwood spot weld gun.Because of the low amperage, I strongly suspect this is really arc welding through a hole drilled in one plate to fuse to a backing metal plate.  Actually not too bad an approach for your application of replacing floor panels because you need access to only one side.  The downside is you got to drill holes in one panel... almost as big a pain as drilling through both panels and doing a pop rivet.Note: a real spot welder requires a fellow to pressure clamp two well-aligned cone shaped electrodes, one on either side of the sheets to be joined - not so easy to do with floor panels.  Secondly, I have done some searching on the net and some trials with my stick welder using homemade clamps with copper tips.According to info on the web, 60 or 80 amps will not do it - unless you actually draw an arc... and that is not spot welding.  One article showed a home built unit for spot welding 26 gage thermocouple wires and the fellow used 450 amps.  Think about it - 450 amps for 26 gage wires crossing!  Obviously 26 gage steel sheets are going to need more amps.I tried anyway, to join to pieces of 24/26 gage sheet steel together with my home-made clamping rig for two 3/32 inch diameter copper tips and my 117 volt AC welder with output at 80 amps - no luck at all.  Just big humming and no weld.On the net, 'Ohio Nut and Bolt' has a great pdf file on spot welding for fittings - mostly for auto applications.  Spot welding even a small fitting say 1/16 inch thick and say 1/2 inch wide by 3/4 inch long needs 9,000 amps!For the home guy, I think the solution for a low cost spot welder may lie in capacitor discharge.  I had an old Metz electronic flash (for photography) that could blow the end off a screwdriver - that was with a capacitor of 450 microfarads charged up to 450 volts.  You can get the same energy but at much high amperage suitable for spot welding by going to 10 volts with a 3 farad capacitor.  High power car audio dealers/suppliers sell these big 1 to 3 farad capacitors for around $80 - $130.  I figure one could charge it up though a resistor (a few seconds), throw a big switch to dump it across your sheet metal for spot welding.  Still, it looks like you have got have those aligned electrode tips pressing against both side of the sheet metal - so I don't see it working out for welding in floor pans.Geez, I guess I didn't help you too much ... but that's my experience.Rick V
Reply:just lurkin'
Reply:Aluminum requires about ten times that power.  Lots of pressure and very little time.  About thirty five years ago in Dallas, Texas we had a spot welder with 150 kva.  If I remember right it had these things called igniters and they were water cooled.  Of course everything was refrigerated water.  I was also wondering about that thing from eastwood.
Reply:I've seen the gun you're talking about. It uses a carbon rod that you create an arc with. Then by pulling the trigger on the gun you pull the rod away from the metal supposedly making a pool of metal (i.e. a spot weld). It probably doesn't work well (or at all). A number of years ago I foolishly bought what Eastwood sold as a "stitch welder" It was supposed allow you to weld sheet metal with an AC stick welder. What a piece of ***t, never got it to work, but I see that they still sell them. One thing I've learned is to buy the right tool for the right job. The best way I've found to make spot welds is to drill or punch holes in the one sheet of metal, clamp it against the other and weld the holes full with a MIG welder.Sure, I can fix it... I got a welder!!!