What Are Dimes in Welding?
If there ever was a signature weld, it would be the “stack of dimes” weld. A pretty stack of dimes says, “This welding job was done by a pro.”
What are dimes in welding? The “dimes” in welding are the hardened, round puddles of metal and filler created during the welding process. They line up across the weld area looking as if a row of dimes had fallen over like dominoes. It finishes the weld, both functionally and aesthetically. Since the technique requires a fair amount of skill and practice, it becomes a badge of honor for those who master it.
The stack of dimes look can vary, from a top-down look to an angled presentation, where you see mainly the edges. Dimes can be created in both MIG and TIG welding techniques. Let’s take a look at how to achieve the dimes look in both TIG and MIG techniques.
TIG stands for tungsten inert gas. It differs from MIG welding in that consumables are infrequently used, and that the heat source is a reusable electrode. Gas is delivered to the weld site to scatter impurities before they can corrupt the weld. TIG welds are generally shallower and smoother than MIG welds. Because of this, TIG welding is most often associated with the stack of dimes look.
In TIG welding, the dimes create an incredibly strong weld because of the overlapping layers. If you’ve ever loaded a pallet of boxes on a shipping dock, a foreman probably told you to “tie the layers off.” That means to stack the boxes so that every box is weighed down by the entire layer above it, not just one box. You alternate each layer’s pattern so that two or more boxes make contact with each box in the layer below it.
The same principle applies – sort of – to the stack of dimes technique in welding. The mass of each dime covers and fortifies the dime underneath it so that you get the mass/weight of both dimes in the same small area. But wait. There’s more to it than that. Since each dime is weighed down by the dime on top of it, you get the cumulative effect of ALL the dimes adding mass to the weld.
As a result, you end up with a weld that achieves the same strength as the base metal itself. When subjected to extreme stress, the metal might fail before the weld.
Dimes in TIG Welding
Creating dimes in TIG welding requires a steady hand and a sharply refined sense of timing. Practice makes perfect, as they say. The old guys have it right this time.
The following comprises good welding practices for all applications, not just dimes:
- Clean your metal. The glossier and shinier it looks the better the weld.
- Avoid gaps. A gap greater than 1/100th of an inch prevents proper beading of the weld.
- As a general rule, use 1 amp of current per 1000th of an inch of thickness.
- Keep the tungsten the same distance from the work as the electrode.
- Use a filler rod that melts when you put it in the puddle, not before.
- Work with consistency. Do the tasks the same way every time.
Clean and Shiny!
Don’t skip or cut corners on this step. Remove all rust, discoloration and roughness down to bright, shiny metal. Wipe it all down with acetone afterward, and don’t substitute parts cleaner or lacquer thinner. Parts cleaner can leave a residue than can degrade the quality of the weld, and lacquer thinner can ignite at weld temperature.
You already know not to leave gaps in your work. You probably also know that gaps happen anyway. But for the stack of dimes technique, extra diligence in this regard pays off. Gaps measuring 1/100th of an inch or greater cause big problems.
So how do you avoid gaps?
- Add more filler and add filler more often.
- Increase travel speed.
- Adjust the torch angle. Too flat of an angle can lead to gaps by running ahead of the weld puddle.
- Keep your filler away from the gas, and the gas away from the puddle. Keep the gas close, of course, but don’t let it touch the filler or the puddle.
- Unevenly cut metal parts create a gap-prone juncture. If you have no choice but to use them, do the best you can, but know that gaps will be hard to avoid totally.
The rule of thumb for TIG welding says one amp per 1/1000th of an inch of metal. But remain flexible, for you probably will have to make minute adjustments here and there. If you plan to weld aluminum, increase the amperage by 50 percent. Double it for copper.
Careful observation of your work in progress makes it easier to adjust the amperage on your electrode. Watch the weld puddle as it spreads. You want it to grow to no bigger than a dime (hence the term). If the puddle grows too quickly or overshoots the size you want, decrease the amperage. If the puddle takes a long time to reach the size you want, increase the amperage accordingly.
Keeping the tungsten the same distance from the work throughout the welding pass makes the world go round. It also helps make the puddles go round – literally. Keep in mind that your machine tries to match the voltage to the distance, in order to maintain the weld cone. Keep a close watch on the weld cone at all times. Make sure the filler doesn’t block your view. If it does, you’re too close.
Repoint your electrode as often as needed to keep your puddles the same size.
Use the Right Filler Rod
Your filler rod should melt the moment it touches the weld puddle. If it starts dripping before it reaches the puddle, it’s too thin. If the melting takes a moment or two after insertion into the puddle, your rod is too fat.
Same Way Every Single Time
Place the tip of the rod into the puddle like you were putting a straw into a tumbler of lemonade. Don’t slide it in sideways, and don’t dunk it in there aggressively. Just ease it into the puddle and go about halfway in.
The first time or two, you might touch bottom, which is not what you want. But don’t worry. You’re developing a feel for the process, and precision will come with practice and experience. The key is to learn what works and what doesn’t. Once you’ve successfully created a couple of nice round dimes, try to emulate that very same motion every time.
It’s like shooting free throws or making two-foot putts. They call it “muscle memory,” because the muscles train themselves toward consistent movement when the rewards are experienced by the brain. Practice on non-crucial pieces of metal as often as you can, regardless of how long you’ve been a welder. The benefits are worth the effort, many times over!
Now Stack Those Dimes!
Creating consistently shaped and sized dimes is a skill to be proud of. Some welders go years without getting it quite right. But now, apply the skill to the practical application of creating a super-strong weld that just happens to look very cool.
As we mentioned before, the bead should look like a stack of dimes had fallen over like dominoes. The finished weld should actually show a small percentage of the round puddle you created. Think of it as if the stack of dimes had fallen over, but that the dimes did not fall completely flat. You can see the fluted edges of each coin, and maybe the top of President Eisenhower’s bald head, but little else, because another dime is blocking the view.
That is what you want – dimes blocking the view of the underlying dimes. Really, the dimes should almost be standing on their edges and just leaned over a bit. This kind of bead is ridiculously strong, probably stronger than the base metal. It’s also hard to achieve on a consistent basis, so practice, practice, practice.
MIG welding consists of using a continuously-fed wire electrode to insert into an electric arc hot enough to melt the electrode and form a puddle on the work metal. It stands for Metal Inert Gas welding, as a shielding gas is introduced into the work area to rout out impurities that could compromise the weld.
Nearly always, a MIG weld creates a liner bead that resembles a caterpillar or worm. It’s not the stack of dimes look that has become synonymous with skill and expertise, but in nearly all cases a MIG weld is as strong as a TIG weld. The problem for professional welders is that customers tend to like the look of the dime weld, and they often feel short-changed if they don’t get it.
So, can you get a stack of dimes look with a MIG device? Yes, you can get the look. Is it a better weld, structurally? The jury is still out on that.
MIG Like TIG
The key to making a MIG weld look like a TIG weld rests with the MIG welder settings, and technique. Your technique will help you determine the effectiveness of your adjusted settings, but start with the adjustments, which are:
- On the chart for determining amperage, go down a line or two (less amperage) to create a slower-forming puddle.
- Adjust wire speed to fit the adjusted amperage. This will be a judgment call on your part.
Take the Amps Down a Notch
First off, you have to be in the ballpark of the recommended welder setting or you won’t get anything, let alone the stack of dimes look. Your skill level should accommodate the variance you’ll encounter with the adjusted settings. If you’re a by-the-book welder and that’s all you’ve ever done, you’ll struggle here. You can always practice, though.
On your chart, do the cross-reference thing with the columns for electrode size and steel size, but instead of using the recommended amperage, move your finger to the left one column, and go with a smaller amount of amps. You may need to tweak that a bit once you get going.
Adjust the Wire Speed
You’ve no doubt heard the term “educated guess.” That may work as your best bet here. With the amperage tamed down from recommended settings, and a certain desired look in mind, you must get comfortable with the wire speed to pull it off. Play with it. Practice on scrap pieces first.
“It don’t mean a thing if you ain’t got that swing.”
With a slower-forming puddle, you have a teensy bit more time to get creative. Some welders who claim to be able to MIG like TIG use the “cursive e” technique to create a round(ish) dime-sized puddle. You simply move the tip as if you were writing the letter “e” in cursive.
Once you have created a decent dime (remember, it’s not going to be a perfect circle) then get into a rhythm, combining wire feed and tip movement almost in dance motion. Getting into a tempo is crucial for consistent dimes. Too slow, and you create too big of a puddle and therefore, too big of a dime; too fast and your dime is too small in comparison with the others.
Overlap your dimes by at least half of the dimes’ diameter until you reach the end of the joint.
In addition to the cursive e technique, there is the “C” technique, that creates half-circles on the work metal. The thing about half-circles is that you don’t know they’re half-circles if they’re covered up by the next half-circle. Finish inside out, so that the last dime you create is on the inside of the seam, if that even comes into play.
The back-and-forth method involves pushing the puddle forward and then pulling about half of it back. This forms more of an oval than a circle, but properly stacked, the bead is nearly as pleasing to the eye as a perfect stack of TIG dimes.
Why it Should Matter?
For superior strength, a stack of dimes weld is clearly a great method to use. In probably 75 percent of the cases, it’s overkill, however. A single straight bead will likely suffice for strength purposes.
It’s just the look. Customers want it, and welders who want to stay busy need to learn how to create it.