just a bunch of pony pipe clamps will give you a set of nearly infinite hand supports for TIG work in general. This old image was during a discussion of making fitted pipe joints while on the bench- But I hope the idea conveys the versatility of pipe clamps as hand positioning welding fixtures?
Here's an image of the tungsten (w/o gas cup) and filler trying to show the amount of movement between puddles can be less or more depending on your travel and the 'swing' angle of the torch 'aiming' the arc cone. In your examples above, I'd suggested you might make this movement less than you're showing as the welds' "puddles" are more elongated than might be ?
I hope this shows a weld that has less distance between 'dips'/dimes/puddles and you can see the edges of the weld is more uniform-less serrated and the bead's overall shape is a bit more uniform with less high and low to the individual dips/pauses/puddles?
Same idea, trying to show a little less distinction between puddles/dimes/pauses and more overall uniformity and that is from less travel per pause, less volume surge and more filler volume uniformity that comes from dipping more often but w less filler.
TIG welds with larger rounded depth then valleys between puddles tend to leave a more ragged edge and that usually results in more tearing along the HAZ in a bend break test- and is more vibration susceptible to edge cracking in a high strain area.
Carl, hope these old images will help make better sense of my post above? I've tried to explain why I make these suggestions but if I'm not coming through clearly I'll trust you'll speak up?
Very helpful, thank you. You have a gift for teaching, time will tell how much aptitude I have for learning!
Bonus points on the welding support suggestion because I already have pipe and clamps. I was wondering what I was going to do with extra pipe, now I know.
I can see that I'm making progress with the stringer beads on plate exercise. The puddle issue I mentioned earlier was because I didn't have enough heat. When I added more heat my puddle flowed better (until the end when it got away from me) and i got a shinier bead.
Those are beautiful beads you posted. I'll try to tighten mine up while I work on uniformity. How much should my filler metal stick up above the base plate for stringer beads?
Carl,
Padding beads don't need to stand very much proud of the plate. What is more of a learning exercise is to keep that profile uniform from start to finish, along w the bead width.
As you light up, and get the initial puddle, and add your first filler dip- you'll create the size of crown of that weld. IF you have the amperage up high (?) the filler will more fully melt into the parent metal, where the same length/volume of dip would crown up much more if the amperage/wattage were lower. Higher amperage and lower profile or crown is fine, as is a slightly taller or more rounded compared to a 'sliver of an almond'- uniformity is the goal.
The crown ht. is not the key focus of padding beads. Not that the profile should be vertical edged at the 'toe and top'/right and left edges of the bead, the uniformity should be the primary focus.
As a side note: TIG power supplies are designed to monitor the arc and adjust for a Constant Current; unlike MIG power supplies trying to maintain a Constant Voltage. IF the formula is Voltage Equals Current Times Resistance (V=IR) then; if you pull the tungsten up- elongating the arc- you'd increase the Resistance of the arc. When the TIG control circuit 'sees' this change of Resistance due to a longer arc length it will adjust the Voltage upward to keep the Current the same.... but the result is still an overall increase in wattage (V*I) or 'net heat input'.
All that means- if your pedal or finger control is left at any given setting and you pull up the tungsten while welding; you will effectively increase the 'heat' just as though you'd pushed more on the pedal or the finger control. It's important, for uniformity, that you're aware of this effect on 'flattening' the puddle profile. More heat/wattage/voltage will resulting in more melting of the parent metal and that will allow any given volume or filler rod to be less built-up and lower the bead's profile.
Also, as you weld along a fixed sized plate a practice piece that can soak up only "so much" heat/welding arc/wattage before the entire plate gets hot. Therefore, less amperage/wattage/power/heat is needed to get the parent metal to melt and eventually the metal will just 'drop out' of the puddle since the heat cannot be dissipated rapidly enough to 'freeze'/re-solidify and allow the parent metal to retain its original shape.
IMO, you need to keep in mind that after a few inches of welding you'll need to slowly and constantly reduce the pedal/heat/amperage otherwise the heat will build up too high for the (limited size) test plate to 'hold' a uniform bead.
In other words; high heat to begin/initiate the puddle, then reduce to continue welding at a given cross section/profile and finally, continue to manually slowly cool the arc wattage in the last 2/3 or even 3/4 of the practice weld if the plate is small enough? This statement is extremely important if you're practicing on 3"x4" plates and less important if you're practicing on 12" x 20" plates.
I'd suggest getting half dozen min. 6"x6" plates and rotate them so they don't get hotter and hotter- if the conditions of your practice continue to change- while you're trying to get uniformity (!!) then practice can be pretty frustrating. By rotating the test plates, letting them cool to room temp between beads, you'd provide yourself a more uniform practice environment.
When you go to boat welding; the overall hull, even of a small skiff, will be huge compared to test plates.
Hope this helps tune your practice a bit more finely as you get your "TIG hand in"?
I had a few different trades mentors, one in several trades and one of them used to say that "Practice Makes Perfect : ONLY IF you're practicing for perfection." If you practice the wrong thing or the trade crafts' skills improperly, coarsely or without very specific mental images (sight picture in shooting sports) then; you'll end up creating poor habits that have to be overcome to actually advance in your skills.
The 'aim small- miss small' admonition to the younger shooters applies to most trade work. I believe the closer to exact your mental imagery of your goals with your hands are during practice- the faster you'll become better/good by keeping an exact set of ideas/goals as focus of your intentions as you practice.
So, while I've given lots of details, if you can imagine the beads as shown, and as described? It's my contention you'd advance your skills more rapidly than just repeating (unknowing) errors and having that negative feedback cause confusion and wandering around w/o much benefit to the practice sessions.
If it were January, I'd envy your ambient temperatures, but now that it's warm here (50F) I'll just wish you well tolerating those working conditions.
You guys are a great source of information and encouragement. I've still got work to do but am seeing improvement. Heck, "seeing" is the biggest change. I'm getting to the point where I can better critique my work, and I'm starting to be able to pay attention to different things while welding.
Sample of this week's practice below. These are 1/8" plates 3x6 inches in size. The weld lanes are scribed just under 1/4" wide. Each row of a plate starts with a single weld button on the ends and in the middle. The idea is to connect the buttons, allowing me to practice continuing and ending on something other than flat plate. I do a row then switch plates, then let everything cool before the next row on the first plate.
I am still too cold at the beginning and too hot at the end, and my consistency needs work, but at least I'm starting to see what's going on.
Shop temps have been ranging from the lower 80s to 100 or so lately. My enthusiasm flags in the upper 80s, but things will improve in another month or so when cloud cover increases and our afternoon thundershower pattern starts.
-- Carl
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Carl, you're showing very good progress for someone that's just coming to alum. TIG.
Couple remarks to follow up. Yes some of the starts are too cold, but... by just pausing before you leave that initial puddle/"start up point" & making sure you have the entire width between your guidelines 'wetted' - you'd have starts like the lowest bead on each plate- which are very much better than the upper beads' starts.
Next is to keep your eyes bouncing between 12:00 & 6:00 or the two edges of the puddle, if they're reasonably uniform to your guide lines then you can skip watching the arc. If the leading edges of the C shaped puddle begin to 'pull back' form the guides ? Then lift the torch just very slightly; OR, add just a little more pedal/slider/amperage; OR slow your dip and travel rate to allow a small fraction of time more before dipping so the puddles are able to flood out to the (now increased) edges of the wetted area.
And on that subject- some of the beads seem to be skewed to one side- more "slanted U's" than evenly concentric " C's " inline. This can come from keeping the torch grip to short- the angle of the arc would then be from the side of the bead, leading to the filled puddle being inclined instead of uniform. I'd consider in those instances a little longer torch head sticking our to your grip (move your hand back on the handle) so the tungsten is 90.00 Deg over the bead, still leading or leaned back but not leaning back AND to one side.
Next beads on these plates are to use one side of those previous welds as one side of your guide line, and add a bead along side with another single scribed line 1/4" or even 7/16" to 3/8" away from the 'toe' of an existing weld. This will give a little different overall thickness- as the previous weld above each new bead will have a little different parent metal mass since there's a weld already added and you're tying into that existing weld as part of the newer beads.
This is how padding plates work and its good practice to tie in to other beads - sometimes at the very 'toe' of the original bead, other times at 1/2 up the side and still in other cases fully to the top center of the previous bead. All are good exercises and represent different welds in different fillets you might encounter in future weld joints.
Last are the stops. You know from the course work that when you stop the Alum. arc that the arc core is molten but then left to freeze instantly. When this happens you'll almost always leave a little crater and that is the most common beginning of weld failure cracks. The reason is that arc core is hotter than the rest of the puddle and more expanded than the outer edges of the puddle- so it contracts more when cooling. Cooling with some 'top puddle' to fill down is good practice.
IF, when stopping you get to the end of the weld and immediately drop the welding current by 50%, but keep a small weld puddle going/molten ..... then, continue to lower the welding current until the puddle freezes at the top; you can avoid all cratering at the end.
While tapering the power, if you add a small bit of filler, not a full puddle's worth of length, while the smaller end puddle is still lit- that molten metal will then fill downward into the chilling/freezing/solidifying aluminum where the arc core is. BY allowing a still molten source pool of metal above the cooling arc core the cooling metal below will 'pull' or fill the arc core from the bottom up with cooled not super heated metal thereby avoiding a crater in the end pool/puddle/bead. You did this successfully in a couple of the beads you show, but not all. So its clear you're tuned to the need to close out/end a bead w/o a crater.
TIG becomes a series of 3 stages; starts, run & ends. Each has a series of methods to master to become proficient and it looks to me like you're well on the road to being good at this welding method.
Surely do NOT envy sauna-like temps for working in the shop! Keep up the good work, your boat will look great.
Work has been keeping me busy lately, but I was able to get a few beads in today. Counting down from the top the new ones are 2, 3, 5 and 6.
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I tried to focus on smaller steps and better heat control. I am reminded of gandrfab's suggestion to find a segment you like and remember what you were doing there. The second part is the tricky bit...
Kevin, your detailed observations are very helpful. I am beginning to appreciate that there are layers within layers to this skill set. Your description of the different options for adjusting heat input connected some dots for me.
It was toasty in the shop this week, my uninsulated garage doors get full sun in the afternoon. I'm thinking of adding insulation to knock the edge off.
Hey Carl,
looks like the bead/puddle/dime size is getting more uniform (ignoring warm up bead #2) with smaller travel and the puddles' more of an arc instead of slewed to one side.
Yes, I'd say there are levels inside levels of skill to acquire in Alum. TIG, Mig too for that matter. You're showing progress, might try keeping a filler rod and off hand glove next to the easy chair/sofa so you can run the filler through your hand even if you can't get to the shop to run beads. It's the weak link- usually- getting the off hand to learn uniformity and control.
I have seen that cooling approach and it would work, but with our hard water the roof would eventually collapse under the accumulated weight of calcium deposits!
We're getting closer to the beginning of clouds and afternoon thundershowers. That'll take the edge off.
In the meantime I'm trying foil/foam sheet insulation on the doors. The afternoon sun bakes those doors and you can feel the heat radiating off them inside. Might extend my working time a bit and give me better temperature stability in the winter.
One down, one to go...
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I was able to fit in some welding practice this week. Each of these rows was started on a cold plate, weld to the middle, then stop and start back up on a hot plate to finish. Numbers are the order of welding. Working on warmer starts and stepping consistency.
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Hey Carl, lots more consistency and a better bead profile. Not too hot, not too cold so your practice is paying off - in improvement.
I'd say you're ready to start adding the other two bead/joint types? Inside fillet is usually the hardest due to torch angle and access but the outside corner fillet is about the best there is. I'd suggest you begin to work on those two added to the flat padding plate beads you're showing.
More practice, this butt weld came out pretty good.
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Moved on to lap joint, still have work to do. My best so far:
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Now that I need to feed more rod I see what you're saying about the importance of developing filler hand skills!
On the lap joint I'm not certain where I should be aiming my tungsten. I've figured out that I need to stay off the upper plate to preserve the edge and have been trying about one electrode diameter away from it. I run into parts of the pass where there I've got a shiny puddle on the top and bottom edges, but the crack at the center isn't keeping up.
Carl, I'd make a few remarks first about joint types. In general I don't find any lap joints in my boat building except when I have to attach a cleat base plate to the gunwale, about the last thing to do. The chines are outside corner, bow stem and keel are the same -even if the angle isn't 90 and the ribs, longs, bulkheads and all are all inside fillets. Some hull plate welds in longer boats- or made from smaller plates are butt joints but they usually involve double mitered edge prep- not square shoulder butt joints- and as a result practicing lap joints is last on a boat builders' list of weld joint types.
Just my view- I always laugh at the online welding material featuring lap joints.... if you lap in aluminum you're very likely creating a corrosion site in the hull. Cleats are a weld around lap, true, and if you don't close well they can leak in a vacuum setting and pull in water if there's any standing on the joint.
So, I'd skip laps for now and concentrate on inside fillets and outside corners which are the vast majority of the welds. Even for practice lap joints are much less productive than inside outside fillets. However, with that being said, in the middle of one of your lap joints (#5) is a great bead, not too proud, not hollow faced, just flush. The puddles are uniform, not too long or short, and edge tie-in is great. SO, IMO, this confirms you're headed in the right direction and with more practice will have fine looking hull welds.
On lap joints, exactly like inside fillets, or even outside corners you 'aim' the tungsten to the un-welded seam between the two parent metal pc - their edges. Now, if you do this but due to the Hi-Freq settings OR not holding even distance from both pc.s; the arc wanders to one edge (toe or top) or the other ? Then you'd compensate that arc wander (most common on laps) by directing the arc cone very slightly away from the 'edge' that is acting as the "arc attraction". When doing inside or outside fillets there are either no edges (inside) or equal edges (outside) and wander isn't as prevalent.
While welding on any joint where you have a material edge you'd try to melt/fuse that edge. If the sides of the puddle were wetted while the center or root is not wetted, then try rolling the torch angle UP so the tungsten is more 90 to the surface- less lead to the puddle. Lead in AC TIG does clean with hot gas in front of the puddle's wetted edge but too much lead (torch angle backward from direction of travel of bead) and the puddle will get 'horse-shoe' shape without the center being molten. This can also happen from 'long-arcing'.
I realize that with pink ceramic cups, depending on the outlet size; the torch gas cup can occlude your view of the puddle. This implies you'll need to either A) roll your head and neck to a farther angle (uncomfortable at best- but done by hundreds of welders) OR B) as Jody Collier [weldingtipsandtricks.com] suggests, use the clear Pyrex cups (he sells them for all torches on his website WeldMonger.com).
Last few items about not wetting the center of the puddle concern the tungsten. First, what sharpening/end tip prep are you using? It is completely counter intuitive that a blunt point gives a sharp arc (narrower cone angle) and a sharp point gives a wide welding arc (much wider cone angle). However since that is true, you may need to consider adjusting your tungsten prep. I use a rounded/domed (but not spherical bulb) tip on pure tungsten and get by fairly well, even on an inverter.
Second tungsten related point; if the center of the puddle isn't wetting out smoothly you might consider your arc length? You have to get the tungsten down close to the parent metal - not 'long arc' - to make sure you have the center wetted out. A long arc brings with it a wider arc cone. A tighter arc length provides a shortened arc cone width REGardless of the tungsten end prep geometry.
Last point (3rd) in reply; you know that required amperage applied is a balance between the parent metal's heat conductivity (away from the arc site) and rate of heat added. IF you add to little amperage then the metal will conduct the heat into the surrounding metal so fast that you can't get a wetted molten (weld) puddle. IF, on the other hand, you add so much welding amperage that your puddle just drops out (falls on the floor) then you're adding more heat/amperage/wattage/BTU's than the metal can conduct away from the weld arc site.
Therefore, you might try just adding a very slight amount more amperage when the puddle gets horseshoe shaped, wetted sides but not in 'crack' or the edge between pc.s in order to add just that slightly extra heat to cause the puddle to be a little larger (more completely wetting a circle) and not C shaped. It's likely you'll have to dial that added amperage right back down once the center wets out. IF not, the edges, especially the top of a lap weld may begin to slump and that edge of the weld becomes irregular as the upper plate's edge is being over heated.
These things will all become more reflexive as hood-time increases. When the center won't wet out- you'll learn to add a bit of amperage and roll the torch up angle (reduce lead angle) and tighten up your arc gap pretty much all at one time in a single puddle's length. I realize that sounds like a lot to consider in one take but I'm pretty sure these reflexive actions will continue to develop as you practice.
Kevin, point taken on lap joint priority for our application, I was following the course work and that was next.
Your suggestions helped with my lap joint, my torch angle was too vertical, my travel angle was a bit generous, and I notice my arc length starts good but then sometimes increases. So many things to keep track of...
Here's my electrode:
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I jumped ahead to open corner and I think it's my new favorite joint.
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This was in a 45 degree orientation, need to try 90 degree next. Then I'll jump to fillet joints.
I had been practicing with pieces of 6063 flat bar that I cut up, but got some pieces of 5052 sheared. My puddle seems to flow better and the resulting welds are more shiny.
