need welding advise

[RICH MUISE]

I'm getting ready to mig-weld 26 holes shut on a cutom 300 front fender for use on my custom (no trim). This much I know: get it clean before welding; welding from the back side with a copper sheet over the outside of the hole will minimize buildup on the outside surface, therefore less gringing; go slow keep it cool as posible.
The problem I am having is that I am trying to use a large welding magnet to hold the copper in place. Whenever I do that I get alot of sputtering with my mig wire. Is that a common problem? Is the magnet too much of a heat sink causing the problem? Do I need to come up with a better way of holding the copper in place? Any tips or advise will be appreciated.

[CDN.SD]

The field from magnets will actually deflect, and otherwise mess up your arc.

I flatten the ends of various lengths of normal houshold copper pipe (1/2") and bend them to a convenient angle, and hold them in place using the still round section as a handle. (Wear gloves, copper REALLY conducts heat!). A little awkward sometimes, but it can usually be managed.

[RICH MUISE]

Thanks for the info...I think I came up with a quick fix nifty idea to resolve the problem. I'm going to use a magnetic base dial indicator holder and make up a long arm attchment(another foot or so) with a copper piece mounted on a swivel at the end of the extention. That should get the magnetic field far enough away from the welding point to not effect the welding. If that doesn't work, I'll mount the arm on a clamp instead of the mag base. I thought about using on of those swivel multi jointed arms, but I'm guessing the joints may have plastic inserts which would be a problem with the welding heat. I'll let you know how it works out.

[glen b henderson]

Rich, I don't know if it will work for you, but a trick that I used filling dozens of trim holes on my Falcon gasser, was to stick common nails through the holes and weld them in place. Once welded cut off the nail and grind it smooth. This requires less time than trying to fill the complete hole with weld.

[RICH MUISE]

clever...I'll give it a try. A while back I suggested we had a tips and hints section...maybe one for shop, one for 57's in specific, one for anything, one for picking up women...,ok, cancel the last one. There's a ton of hints a time savers out there floating around in these old heads we like to share if someone justs asks..It would be nice to have a spot to log them in without waiting for someone to ask.
thanks Glen     ...Rich

[RICH MUISE]

This should work...Mag base is about $10. at harbor freight. Hopefully this will get the magnetic field far enough away from the weld area to not affect it. I'll know once I get my fender back from the soda blaster's. (this is shown in picture on a spare fender)
With the on-off switch for the magnet, the adjustment knob, and everything swivelling, it makes it really quick and simple to locate it where you need it.

[cool57]

This should work...Mag base is about $10. at harbor freight. Hopefully this will get the magnetic field far enough away from the weld area to not affect it. I'll know once I get my fender back from the soda blaster's. (this is shown in picture on a spare fender)
With the on-off switch for the magnet, the adjustment knob, and everything swivelling, it makes it really quick and simple to locate it where you need it.

That's pretty slick! Let us know about your soda blast results. I've heard negatives about residue, even though cleaned off, interferes with paint adhesion.

[RICH MUISE]

I had my last fender soda blasted. The first thing I do after I blast something, sand or soda, is give it a workout with Metal Ready, a zinc phosphate acid. It neutralizes the rust and leaves a coating to help prevent the quick rust over you can get while you're working the part. The zinc phosphate is done pretty aggresively with a skotch brite pad and gets a final rinse with water before force-dried, so if there was any residue on the fender, what I do would have removed it. Also,my soda blast guy told me to rinse it with water to disolve any residue left that he didn't clean off with air.
A word of caution...the metal ready will also leave a residue which can interfere with paint adhesion if not prepared correctly. I found out the hard way that it does not always help with adhesion as the manufacturer says, but depending on WHICH paint you are putting over it. If you need some details let me know so I don't get too redundant here.

[RICH MUISE]

The magnetic base with the copper pipe worked great. Absolutly no distortion of the weld arc.

[RICH MUISE]

Got the fender done a few weeks ago, but I was curious...I was really worried about distortion on the fender with all the holes I was welding (26 of them). I really took my time and went slow, and to my pleasant surprise, when I was blocking the fender out there was no distortion at all, just very slight low areas, about 2" wide or so, evenly spaced around each and every hole, not more than a few thousandths of an inch deep, but still there. I got to wondering if the low areas were a result of the welding, or if all the factory fenders with the trim holes punched had the low spots as a result of the hole punching. Anybody out there blocked a fender with the holes and noticed the low spots? Not important, just curious.
Ball game in 5 minutes........love september baseball........just plays hell with my projects.