#21
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Looks good to me Bart!
I tend to use this method almost exclusively, since it is what I was taught when I first started. Fusion tacking (and welding) with little or no filler. I don't have a foot pedal (just had one fitted to my bigger TIG, but haven't run it yet) so it is just on/off with the HF finger switch. Any tips on a neat & reliable way to cut out radiused patches? I find that snips tend to "rearrange" the surrounding metal quite a bit. I suppose making the hole first and the patch to fit would be easier than the other way around (like I tend to go at it when not thinking - ie most of the time!) Barry |
#22
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I tend to use this method almost exclusively, since it is what I was taught when I first started. Fusion tacking (and welding) with little or no filler.
I don't have a foot pedal (just had one fitted to my bigger TIG, but haven't run it yet) so it is just on/off with the HF finger switch. Any tips on a neat & reliable way to cut out radiused patches? I find that snips tend to "rearrange" the surrounding metal quite a bit. I suppose making the hole first and the patch to fit would be easier than the other way around (like I tend to go at it when not thinking - ie most of the time!) ~ Barry Barry, foot pedal or finger control makes no difference, the idea is just a quick burst of heat to expand the edges & melt them together as you well know. I feel that once people get the hang of it (and it’s not that hard) going back to tacking while holding a filler rod will seem almost pre-historic Last edited by John Buchtenkirch; 08-31-2009 at 01:41 AM. Reason: perfection |
#23
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Bart, looks good for your very first attempt at a different style of welding. I will give you some thoughts or ideas for the future. First off when I install patches I stay away from square corners as much as possible even though that’s what you end up with if your cutting pieces out with a wiz wheel. Square corners tend to planish out to a knot (high spot) and are slightly problematic to weld. The corners don’t have to be perfect radiuses, just eyeball them to about a silver dollar’s radius and I think you will notice final finishing of the metal becomes easier. Less starts & stops generally means a more consistent bead. In the future tack all your tight fit spots first and then hold a piece of the appropriate sized rod in the gap of the looser fits while tacking. Finally I don’t know if your dinosaur tig has an adjustable high end setting but I wonder if people without one could put some sort of mechanical stop under the actual foot pedal to do the same thing ? ~ John Buchtenkirch
What is this high end setting that John is referring to, don't think my machine has it but what does it do? I got an old miller 330A/BP. Some really great threads on this site, i thought i knew how to do something until i started reading into some of these threads and i now realize how much i've got to learn, good thing i'm only 60 and have plenty of time to learn. Thanks, oj |
#24
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Oj - I have the same TIG machine. Our machine only has 3 major settings (the big lever) The large knob at the top center of the panel is the high end setting. It is based off a percentage of whatever the major setting is. So if you have it on the 65a notch, you can turn the knob to 50% and your max output would be 32.5a . .. in theory...
John- I know about using rounded corners , and I usually do... I had a bad day at the day job that day and was frustrated and just wanted to get something done on the car... sooo I was a little impatient and just kinda slapped it in there. It did planish out pretty well, except where I over stretched one spot. I left that for a later day, still haven't fixed it yet |
#25
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John, your explanation makes sense. I did it your way more or less since I started as I found out that if feeding in the heat slowly the edges tend to pull apart rather than flow together. It's yet another proof that going about things slowly and carefully is not always the best way. To learn something new it's useful to learn where the limits are both on the high and the low side. It does not cost more than a few pieces of scrap metal.
David, your advice is taken. I will try to get back using it. Years ago, that's about how I did it. But it does require some retraining if not done on a regular basis. At least it does for me. The last panel I welded in on my Alfa was started out using it. But then the oxy backflash valve acted up and it was back to TIG. Probably have to ditch that valve and do some coupons first. If I were told to use only one welding technology, yes that would be O/A. But I do like to use them all. It may also be a similar problem using OA as TIG, that with little experience we tend to chicken out and not feed in enough heat. I believe that's my problem at the moment not having done much sheet metal welding through the summer. |
#26
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Someone had asked me how I cut the radiuses on the corners. It’s pretty straight forward as you can see in the photos. After I remove the piece I just trim out the angled corner cut using snips to cut an eyeball radius cut. The third photo is my 2 favorite tools for doing this type of work. The right angle abrasive cut off tool is an Ingersoll Rand industrial tool I paid over $300 for about 20 years ago. You guys are lucky, they now have 2 similar tools on the Mack tool trucks for about $140 to $160. After using the right angle type you wouldn’t want to go back to the muffler clamp cutting type. I like the snips with the offset jaws because they can cut tighter radiuses but my next pair is going to be the
!1rc1.JPG !1rc2.JPG !1rc3.JPG As far as the adjustable high end setting goes I don’t know if all tig welders have them but it’s pretty much necessary to do high speed tig tacking the way I do it. If you can’t adjust the high end you will blow holes thru the metal for sure. I really doubt anyone could stop the foot pedal or hand control at the right spot time after time. It’s really more a technique than an actual welding skill --- it happens so fast you don’t have time to watch a weld puddle or correct your technique. If your panels fit up nicely and your welder is adjusted perfectly (that’s where the adjustable high end comes in) 20 or 25 tacks per minute is certainly doable, it’s just that fast once you master it. ~ John Buchtenkirch |
#27
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Ref tig tacking a tip I learned from Contour Autocraft as follows,
1/ dont clean off the rough edge of the sheered metal. the slightly raised rough edge acts very well as a filler.. 2/ with a realy good gapless fit give the metal either side of the join a quick pre heat with the tig, ie about 10mm from either side of the join give the metal a quick flash with he tig, this in theory closes the join making the edge even tighter and less likey to blow through especially with the "rag" left behind by the sheering process.. hope thats clear, took all of 10 minutes to learn the technique and longer to type an explanation... |
#28
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Quote:
I’m sorry but #2 doesn’t make any sense to me. If you read my post #15 and look at my photos in post #18 you will see I tack decent and very fast with just the flash . ~ John Buchtenkirch |
#29
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I learned the same way at Contour!
#2 will help if you have a (small) gap between the panels at the point you want to tack. The heat will expand the metal either side to push the gap closed. Waiting a few seconds for the previous tack to cool and shrink will have the same result. The Contour method, like DG's doesn't use clamps and you can also manipulate the gap a little by moving the two panels relative to each other (typically held in your free hand) Once again you're better off taking a little time to get good fit though! Your method sure sounds interesting though John - will have to try. Barry |
#30
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Quote:
I have always praise the results you get and I have said on several occasions that I think that Randy does fantastic work. I have never said anything derogatory about anyone or the work they do either on the board or in private. ( Edit) Johny I have just read the thread and I cannot see that I said anything that was criticism, My replies were in response to what you said. Once again I apologize if you took what I said as such. David
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Metalshaping DVD. www.metalshapingzone.com Metalshaping with hand tools on youtube http://www.youtube.com/watch?v=IGElSHzm0q8 All things are possible. Last edited by David Gardiner; 12-01-2009 at 10:10 AM. Reason: add comment |
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