tig and sfi specs

A Tig weld puddle surface that looks either convex or concave should be fine depending on the type of weld joint (such as inside corner, flat, outside corner). What you don't want to see is an under cut edge looking puddle.

Striving for a good fitting joint is something to shoot for. But remember that what makes a "good" joint fit isn't the same for all materials & thicknesses. A super tight fitting joint on say 1" x .058" cm tubing is most definitely the way to go. But the same super tight joint on a piece of say 1.625" x .134" ms is really too tight and can cause problems.

Remember just because it's a Tig welder doesn't mean it doesn't sometimes need some penetration "help" from either a looser fitting joint, or a beveled edge to that joint.

Also don't get all caught up in the "make the Tig puddle as small as possible" thinking. The truth is that the "correct" puddle size is usually directly related to both the joint design & the thickness of both parent materials. A super tiny weld puddle on a tight joint with a piece of .049" thick cm wing strut material might be fine. But the same size weld puddle on a tight joint done on a 1.625" x .083" cm tube is asking for trouble.

And along this same thinking the opposite would also be true. A big puddle on a loose joint using the thin .049" thick material will most likely result in an over heated weld joint.....that is if it doesn't flat out torch a hole in it trying to fill it.

Dave Maxwell wrote:will practice some more tuesday and maybe post a pic.

That's one of the most important things you can do, just practice & practice some more. Learn what parameters work best for you for any given tube OD & thickness (tungsten size, filler rod size, amp range vs pedal range vs joint fit, etc, etc).



Some other tips.......

If you are able, place your tack welds where you plan any given weld pass to end. This way it's easier to melt the tack into the puddle as the base material & filler rod are already up to "temp" by then & aren't cold as they would be if you were starting a weld pass on/near a tack weld. Placing the tack at the end of the pass also lessens the chance you will have to make an abrupt stop to welding if your unintentionally over heating the end of the pass. This is because the tack will act as a heat sink allowing you more gradually stop at the end of the pass as you melt the tack in. This technique is even more useful with Mig welding since starting on top of a tack is the last thing you want to do when using a Mig. This is because of Mig's colder "start" vs Tig.

If you happen to fit/grind a weld joint a little too loose in a spot or two, this is also a perfect place for a tack weld. The tack will act as additional filler material filling the gap & helping to keep the weld puddle temp from spiking as much as you run over it and slow down & spend extra time (and generate more heat) filling it.

Drill a small hole in the general area of the weld joint (3" to 5" away) to relieve internal air pressure build up from the weld heat. This will help prevent a puddle blow-out that can screw up the pass.

Dave always has good info I like to set up 10amps for ever .010 but it can go up or down.

Dave Maxwell wrote:but they arent uniform in appearence.

Got to thinking about that and while perfectly uniform Tig puddle widths & stack lengths is something to shoot for, realistically only a select few people can pull it off 100% of the time. And even then it's usually bench welding that makes it possible where your sitting comfortable & relaxed while welding. Uniform puddles become harder to achieve as welding position/welder comfort gets worse (welding on the car while in/on/under/upside down). So don't be too hard on yourself if your weld puddle isn't 100% uniform........getting good weld penetration is more important than "looks". When you start practicing on thicker stuff like tubing you might think about chopping up a few of the finish weld joints & see how much weld penetration your getting.

About the most uniform weld puddles I have ever seen were on older Don Ness cars & welds I saw David Wolfe do in the past. Both were amazingly uniform like a perfect over lapping stack of dimes.


On the other hand my welds do vary a bit in width & at times can be larger/wider than what some people might consider "desirable" (especially on thicker ms).

I usually use a .0625" (1/16") 2% Tungsten & a #4 cup on most everything ms & cm up to about .134" thick. And the .09375" (3/32") tungsten on .1875" thick & thicker material, (or where I have to use a bigger OD filler rod than normal).

Dave Maxwell wrote:What size filler rods do you use?

For tack welding I use a .045" filler rod most of the time on cm & ms. But I have on occasion also used .035" Mig wire for tacking really, really thin stuff. For the actual weld pass probably 90% of the time it's either .045" or .0625" OD steel filler rod for both cm & ms.

Dave Maxwell wrote:the smaller cup size. besides tighter areas, what does it do?

That really is the main reason for a small #4 cup, getting into steep angle inside corners. But even with the small #4 cup you will find sometimes some joint designs will still require you to extend the Tungsten out far enough to possibly hurt gas coverage. In this situation you must make sure your not welding in a breeze. Close shop doors if you have too & turn off fans. Clamping a piece of card board or sheet metal to the back side of the a steep angle joint can help to trap more of the argon & help keep air away from the extended Tungsten & weld puddle.

Dave Maxwell wrote:any good videos or books you recomend.

Don't really know of any videos, I just learned with a bunch of practice.

Should also mention that if you need glasses to read small print, you probably also need glasses to Tig ms & cm since a small(ish) puddle is the norm. When I first started learning to Tig, at first I didn't realize I was actually having problems seeing what was going on. I could see the bulk of the puddle form, but I couldn't see down into the arc at the puddle's leading edge. Cheap drug store reading glasses made a night & day difference in my ability to see what was going on as the puddle formed & my Tig welds looked 100% better after I started using them.

Dave my Stepson use to work for Ness for about the last 12 years.... he is a damn fine welder. and now works for a ProStock team.......


Randy

www.weldingtipsandtricks.com

for tech and videos

sorry the vidoes dont work ya, i have the slowest internet you can get and they worked for me,just slow loading tho. i have to use the cheap reading glass to read and see this dam computor, tomarrow im going to use them welding and see how much better i can well.

the Coug wrote:Dave my Stepson use to work for Ness for about the last 12 years.... he is a damn fine welder.

That was probably a great learning experience for him.

I may be wrong but I'm pretty sure that Ness can be credited with being the "father" of the modern door car cage layout behind the main hoop. Before most all the P/S cars had the same basic old style rear 4 bar layout supporting the main hoop, two bars straight back & two bars forming the "X" (like Don Hardy and Alston). But Ness's design of looping a bar up over the top of the tubs allowed more attachment points for more diagonals. That really made things a lot more rigid back there, and allowed the main frame rails to be hung higher in the car for more tire room and a lower body stance.

If Ness wasn't the first guy who did the cage this way back then, he was at least one of the first.