All You Need To Know About Overhead Stick Welding
All You Need To Know About Overhead Stick Welding
The easiest welding positions are horizontal and flat, they are also the most popular. On the other hand, welding vertically with a stick electrode is the challenge. Vertical-stick welding may not be very popular but definitely requires more skill and attention to detail than horizontal and flat welding. Here are a few things you should know and common mistakes that you should avoid to become a good vertical-up welder.
Choose the Correct Electrode
If you are going to weld in a position that is steeper than 45 degrees, you have to realize that you will be against gravity. The 7018 electrode was designed for this very purpose. Classed by the AWS (American Welding Society), this is the perfect choice because the 7018 has a lower content of iron powder. This particular electrode makes a weld puddle that is able to freeze almost instantly and won’t drip off while working. You can also use the AWS classed 6010 stick but this electrode requires a certain whipping or stacking technique in which you pull the stick out of the puddle and put it back in intermittently. You can use the 6100 for the same kind of work but 7018 is known to give better results and a quicker weaving pattern.
Of course if you have to overcome poor surface condition, you can go for the 6010. Be prepared to put in a little extra time and skill when working with this. On the other hand, the 7018 requires less skill and it is quicker to weave. Rookie welders often mistakenly go for the 7024 when vertical stick welding, however, this drips a lot throughout the job and lacks proper fill.
Perfecting the Shelf
Flat, overhead, horizontal, vertical-up, and vertical-down are the five positions of welding. Out of these 5 the overhead or vertical-up position is the most challenging because throughout the entire welding process you are constantly fighting gravity. Slow speed and uphill welding provide the best possible penetration and this technique is preferred on any material heavier than sheet metal. On the other hand, if you are working with sheet metal, the welding can also be done downhill because you don’t need much penetration.
To better understand overhead welding, compare it to bricklaying. Similar to bricklaying, the welder creates a weld slowly from the bottom and only works on a small section every time. The welder keeps working on top of each weld that was previously laid. Every new lower weld serves as a base on which the next welds would be made. The lower welds are known as the “shelf” or “weld shelf. A weld shelf typically has to be twice the diameter of the electrode.
If you are welding with the 7018, you can zigzag to and fro, allowing time for each puddle section to freeze before the next step.
For the best possible fusion and penetration, it is essential to hold the electrode uphill and keep the arc short. During weaving, make it a point to maintain focus on welding the edges of the joint first and then give a short pause before moving on to allow the beads at the bottom to cool down and form a sheaf. Note that trapped slag in a weld will not only look sloppy but will also compromise the strength of a weld. So avoid this and keep a close eye on the puddle at all times to see if the slag is dropping from the sheaf. If it is, immediately move the electrode away so that you don’t lose the arc.
If you are using a 6100 electrode instead of the 7018, the regular weaving technique would be replaced by a stack. You can compare this stack to poker chips just to have an idea of what the finished weld should look like. Every chip you weld should be creating a shelf. The trick here is to keep the electrode at the root of the metal. Once you form a puddle, pull away the electrode and let the puddle freeze. Once it freezes, apply another one to the forward tip of the weld. Keep a steady course and repeat each step very carefully until you are done completing the entire weld. The puddle should be about twice the diameter of the 6100 that you are using.
How to Avoid Undercutting
Undercutting can ruin a weld; this is one error that should be avoided at all times. There is one way to avoid this, reduce the flow of current and slow down your speed. If you think that you may end up undercutting because the puddle is too big, it is a good idea to reduce the puddle size. This will give you better control over the entire process. To be a good welder, you have to maintain focus on the puddle and learn what characteristics it should not have so you can predict when the weld is about to go wrong and fix it immediately. While the puddle is forming, the slag has to drip from the sheaf, no matter which technique you are using. Ensure this and the resulting puddle will be strong enough to stay in place.
Reduce Amperage settings
Since you are going to be working against gravity on this one, the amperage settings have to be low so you have complete control. Welding on a flat surface makes gravity your friend and you can work with higher temperature. In the case of vertical up welding, if the amperage settings are high, the weld will not freeze in time and may drop out. Always use low amperage settings for a perfect vertical-up weld, for example, if you working with a 0.125-inch 7018, keep power up to 120 or 130 max. Similarly, working with 0.125-inch 6010’s, the amperage setting should not be more than 90 to 100.
Working with Flux-Cored Welding
A new feature has taken over quite a few construction markets. This is the Flux-cored welding. The only difference between this kind and welding with the stick is that you get a continuous wire feed, whereas, in stick welding you have to keep inserting fresh electrodes. This is helpful if you are welding for a longer duration as the feed is uninterrupted. In this case, the procedure for the 7018 electrode stick will apply if you are using the weave technique.
If you plan to become a certified welder, practice with vertical-up welding because that requires greater skill and precision. If you get certification in vertical-up welding, you are automatically certified at flat welding. So, use these tips and tricks and become a great welder!
Check out the Longevity website (www.longevity-inc.com) or YouTube channel (www.youtube.com/longevitywelding) for more details and information about equipment for different welding and cutting processes. Longevity has the right machine for your exact application, so take a look and choose what is the best fit for your materials, product and needs.