Here's what I do...

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This is a panel that I hand formed as it is not available. The car is a '71 Porsche 911 coupe. The rocker and inner rocker are all new from one of the reproduction sheet metal houses. But to complete the side, I had to patch in this piece. Now, in our world of restoration, butt welds are the most acceptable even thought I have a couple different ways of flanging a piece. Somtimes that is prefered like on a floor pan replacement.Looks like a little rust is forming already. Anyway, I stitched it in there, welding high, then low, then in the middle and so on. Kind of a messy way to weld things, but it keeps the heat in the panel down and no distortion. I did this with my little Lincoln 100 which I agree I have to upgrade. Other than the upgrade, what suggestions can be offered for this procedure? I'm here to learn. You can take a look at my first post in the Introductions forum for a little background.http://www.weldingweb.com/vbb/showthread.php?t=4729Thanks.
Reply:I have done that before. It's not fun because you have to do exactly that...stitch weld it in, like torqueing a set of lugnuts.I would think the small lincoln 100 would be well suited for this. That's why I got my weldpak. I couldn't do any thin stuff with my larger setup. I hate that kind of work though. There almost always is one section that still has rust in it that just doesn't want to weld. It's not like you are welding onto the end, it looks like you are welding this piece into the middle of something. Ugh. I don't envy your work. But I sure do like the finished products!!!!
Reply:Thanks for the reply. I think I'm going up to a 175 plus, or at least a 135 plus. The reason is even though I understand the varying current due to stick out, I think I'd rather not have to be dependent on a tapped machine. Somethimes, and in some difficult positions, I think a setting in between what I have would help me. You're right, the metal can be of varying thicknesses along the same weldment because of disc sanding, rust removal by sandbalsting, etc. Gotta get it right on the money, or I either build too high or burn through. Don't have enough time to run a nice puddle and dial things in with wire speed. I always snip the ball off the end for a fast start and get out of there as soon as I start a flow. Just tacking alone would take forever to complete a weld and leaves a lotof pin holes between tacks if I don't examine every fraction with a lens. Of course, I will do a little brazing to touch up after grinding to fill a hole or two.Like to hear from other sheet metal workers or body guys. Or anyone in general about their technique. I have been lurking on the Miller and Lincoln boards for ideas on equipment, but for this thin stuff, I don't think it makes a heck of a lot of difference, or does it?I thought about GTAW, but I figured that might be tough lying on my side on the pavement.
Reply:I try to stay away from body work...it's an art and I am not an artist...but, it seems like a little dc tig welder would be the cat's meow in a situation like this.  No filler, just shoot for near perfect fitup and go to town.  Maybe it's just too slow, but when you are dealing with a classic, speed is not what you are shooting for, really.  Just a thought.Smithboy...if it ain't broke, you ain't tryin'.
Reply:I am impressed.  Great job forming. As suggested, if you are doing a lot of that stuff why not look for a DC Tig.  On the one hand it might seem slower, though clean up will be easier.  Keep your MIG for tacking.  Tig would work alright if fit up was tight. I've never tig welded overhead, however.  I just finished welding a large Valet Cabinet( box where they keep your keys) out of 14 gauge sheet.  I used oxy-fuel (similar to TIG) to weld the seams. Not including fit up and tacking, it  took about one hour and a half to weld one 6 foot seam, and two 4 foot seams without filler.  Though clean up was a snap and no pinholes.
Reply:Originally Posted by smithboyI try to stay away from body work...it's an art and I am not an artist...but, it seems like a little dc tig welder would be the cat's meow in a situation like this.  No filler, just shoot for near perfect fitup and go to town.  Maybe it's just too slow, but when you are dealing with a classic, speed is not what you are shooting for, really.  Just a thought.
Reply:I think you will find that if you braze the piece in you would have better results with less clean up and pin holes.  Use a low heat brazing rod and map gas with a pencil tip.Neil
Reply:Hi Zeke;Nice work!Here is my suggestion: take a welding course.   Seriously!    The reason being is that a good course will get you exposed to a lot of techinques that may be applicable to what you are doing.    Beyond that exposure to differrent machines and processes.   Yeah a bit of money might be involved but you get back a clearer understanding of how to pursue your restorations.As to machine suggestions; do understand that the automobile manufactures reccomend MIG on all recent sheet metal.   This due to the high strength alloys used.    Now your Project car might be to old to worry about that, so don't base all your descisions around that piece of advise.     I believe that part of the reason for that suggestion is the low heat input that MIG afford one.    The only thing that might come close is TIG but I'm not a practitioner of that art form.    I usually associate TIG with somebody welding at a bench, I can't imagine what it would be like trying to TIG some of those seams upside down or vertical.   Of course if the body is free to be rolled around that probably isn't an issue.AS to welders I have a friend who is a hot rodder and does some amazing work with an 110 volt Miller MIG.    I have a 240 volt Lincoln SP175 plus.    I would tend to agree that in these class ranges the hardware from the two manufactures is about the same, so I wouldn't worry about selecting from either Lincoln of Miller.   Some of the other brands though may be an issue.    For sheet metal I do believe that the tap free machines are worth the investment.    There is a remote possibitiy that moving up a class or two with respect to MIG might help if the machine has extended capabilities.    The problem with the larger machines is that they don't always have the low end control that you need for the lighter sheet metal.Is your machine a MIG or flux core welder?   For some reason I was thinking that the 100 was a flux core machine.   If that is true then you really do need an upgrade to a MIG.Given all of the above, the first thing I'd do is to upgrade to one of the true MIG machines from Lincoln or Miller.   The 220 volt machines might be a little more versatile but I'm not willing to say they are required.    If you expect to ever need a heavier duty cycle or the ability to work on thicker materrials then get the 220 volt machine.   My suggestion would be the SP175, but that is me.The one thing you will learn about welding is that it is very difficult to get one machine that will do everything you want done.    Well within a reasonable price       From what I know of TIG it could be very useful to you also, but not as your primary machine.    MIG's seem to be the preferred machine to invest in by most guys into automobiles.    Atleast as a starter.ThanksDaveLast edited by wizard; 04-02-2006 at 01:45 AM.
Reply:Since you are dealing with pretty much sheet metal, there are lots of smaller dc units that would work well.  I have heard good things about the thermal arc line...their small tig units are used by GA power and their weldors love um.  Very small, very light, good arc characteristics.  There are lots, as I say...ask the guys that do restaurant equipment.  They will know the best stuff for sheet.Smithboy...if it ain't broke, you ain't tryin'.
Reply:Actually, TIG is used a lot in the automotive customization arena. Go to www.project33.com I actually use on of their pictures of a guy TIGgin a piece of sheetmetal, looks like a headlight bezel.
Reply:I'm not trying to say tig is not used, just that most guys into this as a hobby start out with a MIG.   I geuss one could make the argument that since this is a hobby speed isn't an issue also.   The reality is though that a MIG of reasonably size will also do well when working on frames and other areas where volumne of weld becomes an issue.I mentioned in another thread, that is similar to this one, that an investment in a welding course might pay off.   Ideally you would get exposure to differrent processes and techniques plus the exposure to differrent hardware, that would make understanding ones personal needs easier.The other issue is that I've never TIGed in my life.    Just a bit of stick and MIG, with even less brazing.   So while I can see where TIG would be usefull, I just don't see it as an all around solution for autos.    At least when alying out the same number of $$$$'s for hardware.   I'm open to haivng my mind changed though.Dave
Reply:Wizard, your point is a good one.  I guess I was thinking of this mainly as a leisure activity and thinking that this particular car (antique porsche...gosh...I am calling a car that is younger than I am an antique...double grimmace) might be a good candidate for a slow methodical process.  Once you factor in grinding and sanding, it might not be too slow anyway.  Like I said earlier...body work is for folks with a bit of artistry in them and that excludes me...Smithboy...if it ain't broke, you ain't tryin'.
Reply:ZekeI took an auto body course a couple of years ago and a welding course a number of years ago.  They didn't use mig to do any of the work.  Everything was done with O/A and then a thin layer of filler.  Body panels are seldom welded the full length.  They are normally tacked.  In your case because you are adding into the middle of an existing panel you have to weld the entire section or learn how to do leading.If you do any brazing on it just get the metal cherry red at the seam and hit with the brazing rod after dipping into the flux.  Keep a bucket of cold water and a rag close by and hit the brazed spot with the wet rag afterwards.  It will keep the metal from distorting.If you're any good with a stick buy yourself a good stick machine.  You'll be able to do much more with it than you can do with a Mig.Your working on a classic.  Take your time and get it right.Also, I didn't notice any sanding marks on the panel.  Are you using a high speed air sander with 36 grit fibre disks to get down to the metal?  You need those marks from the sanding for the filler to adhere to.Neil
Reply:Sorry, I have been away and haven't looked in at the thread. Thanks for the advice. I'm headed toward the SP175plus. Me thinks TIG would be difficult in the positions I need to work in. Sometimes I can only get one hand in there.I already do a lot of brazing. I like brazing and can contol it pretty well. I did take a course in gas welding, cutting and brazing at the community college. I might go back for GMAW. (That's what they call it.) I should practice my O/A technique too, as I'm not as good as I once was. A nice hammered butt welded with gas in a sheet metal panel is hard to beat ( sorry, couldn't resist).And, I do lead as well. I don't have any pics on this computer of the last car I did the same rocker panel on, but it was finished in lead at the joint. I just didn't trust bondo there although I use as much bondo as anyone skimming panels and sanding it all off.
Reply:Try using the thinnest wire in your welder you can get. .023 will be much better than.030 for sheetmetal work.You don't need a bigger welder, as you can already burn right through your material easily with the 100. Wire speed, feed/ push rate, and stick-out will determine how well you hit the sheetmetal. A tiggy would be nice, but not nearly practical for all the oddball angles and potential dirty old steel. Low heat braze, not regular bronze, or silver/lead soldering will do the trick. Your welds look fine for the job at hand.Remember, too much welding will just make brittle edges on old frgile steel sheet. This is NOT a '55 Chevy. I see better results with a combo of welds and braze.
Reply:Wow. Found this old thread. I'm a bit embarrassed by the looks of the picture. I know the job turned out great because I saw the car painted and finished.I did take several quarters of welding school subsequently to this thread. I'm doing some nice TIG work in steel and a bit of AL. My MIG work at school on thicker metals was all A graded.Finally, I'm using O/A with an aircraft tip to do some of the continuous panel welds. A long road to here.