The PAD WELD
One of the 1st exercises I performed as a welding student in High School was the pad weld. As a student back then, all I wanted to do was weld 2 pcs of metal together and try to break em. At that time, I didn’t realize how much this exercise built my skills.
I personally think the pad weld is one of the best exercises available for both building basic and advanced welding skills.
Specifically the reasons are as follows. Ease of setup, high arc time, low cost, easy to evaluate, and builds bead placement skills.
Ease of Setup
I know that many instructors will have varying opinions on the importance of welding students being able to gather materials, cut, prep, and bevel them.
I think a need for supporting skills for welding exists, however, if I can primarily have students spend time on striking an arc vs do ANYTHING else, I do. The manual dexterity skills of a welder are what separates us from other jobs. I want the primary focus on welding at all times. The other things are secondary. Yes, students may just be motivated by “Building” something cool like the schools latest project taken from industry with cheap labor and no overhead…Sorry, another topic.
So to setup, I need a pc of flatbar maybe 2″x4″x1/4″ and I’m good to go. But really, any piece of material sitting around is suitable for welding a pad weld. If TIG welding, maybe some prep time removing mill scale if any exists.
Since the pc can be used many times, the daily setup nothingothert than getting your pc out and welding.
Compare that to the time needed to cut 2 pcs, tack em together, and weld 2 beads and throw it away. So if you’re in class or teaching a class and searching for some way to stay busy or keep students busy, the Pad Weld is always there.
With many processes, the majority of waste comes from what is normally referred to as “Production Factor”. This is a percentage of actual arc time in a given period of time. In a typical welding class during shop time, a production factor of 30% is about as good as it will ever get. When preparing materials for a single bead, tacking them together, and welding is all part of “shop time”, that factor will go down a great deal.
During the start of training with new welders, tasks as simple as just tacking a tee joint together can be a time-consuming process that results in a joint that often has only 2 to 6 beads run on it.
Additionally, the time chipping, cleaning, looking at a fillet weld may very likely be more than that time spent working on a bead on a pad weld. I’m not suggesting that tee joints are not needed, just when they are introduced. The key to developing the muscle memory and ability to see the puddle is repetition. The more you do it, the better you get. The quicker I can have something to weld on, the less time I spend prepping. Cleaning a bead on plate takes much less time than a fillet welded tee joint.
The pad weld exercise can use one pc of 2″x4″x1/4″ flat bar for 100 hours with no problem. If you count time as money, then the costs become even greater. Even after students have moved onto tee, lap, butt and corner joints, keeping the pad weld available for those times when materials aren’t available or maybe a new challenge is needed but spending money isn’t an option.
So even after a student has “mastered” the pad weld and moved on to fillet welds or groove welds, moving the pad to the floor or under the table can add a new dimension to the students experience. Even welding flat sitting on a floor can be a challenge compared to doing the same thing on a table.
Easy to Evaluate
Though a bead is a bead is a bead, looking at a fillet weld or bead in a multipass groove weld can involve more discussion with the student to talk about what is going wrong. If they haven’t developed basic skills maintaining work/travel angles and arc lengths then the fillet welds can be very difficult to evaluate what is really going on.
One of the key skills that are very easy to evaluate using a pad weld is the ability for the welder to control bead placement. A pad weld can be evaluated for how well the beads are placed without even looking at it. It could be just felt with the fingertips (after being cooled of course),
Bead Placement Skills
As mentioned above, the ability to evaluate how well the beads are is pretty simple. If the surface is smooth and consistent, then the welder is in control of where he/she puts the metal. If the hills and valleys vary from one part of the plate to another, then bead placement skills may not yet be fully developed. But how can a pad weld help with other welds?
Well, here is my theory. If a welder has the ability to run a single bead from point A to point B is any position and progression, then the next thing they need to control is WHERE they put the weld. It doesn’t matter if its a fillet weld or groove weld, they have to “follow a path” and be able to respond to changes in electrode length, surface contours, visibility, etc as they weld. As each bead gets placed, a slightly different “path” is laid down for the welder to follow OR make a decision to NOT FOLLOW in order to straighten things out.
As a student “Masters” his or her pad welding in normal positions, they can be challenged by relocating the pieces to increase difficulty.
The pad weld can be the core skill building exercise that can be done at any time. Similar to being an athlete that specializes in a single sport but still wants to build skills, reflexes, and coordination. They may do simpler tasks to maintain and build sharpness even though they are not like the “real thing”. Just think how sore your head would be if the only thing you could do to improve boxing skills was get out there and box with a real person.
Where is it useful besides learning?
Besides building skills for welding, there are applications in which being able to perform a “surfacing weld” with smooth layers is of great value.
In one case where it was of great value was while I was in the US Navy. We had one project that occurred on multiple tended units (submarines) that required an electric generator rotor to be removed from the boat, moved to the tender, and rewound, then returned to the boat for installation. The rotor was larger than the inside diameter of the aft escape hatch. The outside machine shop (38A) would setup a machine to cut the excess material from the ID of the aft escape hatch, the rotor was removed, rewound, and returned to the submarine. All of this took a good bit of the submarines “refit schedule”. So the subsequent weld build up and machining of the hatch was a critical part of the boat getting underway on time. The smoother the 300 series stainless steel buildup over the HY 80 hull was, the quicker the machining went. The ability to deposit those smooth consistent layers also made it easier to measure during welding and make sure there was enough but not so much welding time and machining time was wasted.
My 1st welding job after getting out of the Navy was at Lambs Machine Works in Memphis. This machine shop performed all kinds of machinery repairs. In many cases, buildup of worn sections was required and the surface finish of the buildup was critical.
Don’t underestimate the “bang for the buck” that is to be had by the “Pad Weld” it is one of the most time efficient ways to develop the connection from the arc to your hands through your eyes and brain, PERIOD! The manual dexterity developed by the ability to maximize the arc time during practice is unmatched by any other exercise.
Though it may be considered unchallenging by some, modification of the conditions in which its done can make it quite challenging. How about some mirror welded pad welds? Or would you rather the time to cut, prep, and fit some new pieces just to make a mess on them in just a minute or two?