Tack welding is a temporary way to hold welding components together, making sure each component stays in the same position, maintains alignment, the same distance, etc. until you can finish welding. Tack welds are a great way to set up welds without using fixtures and are typically very short welds.
Tack welding is usually done using the same type of process used for the overall weld. An example of this would be the way electron beam tack welds (made with less power) are done for welds done with electron beam welding. Also, if the final weld is done while the pieces are still clamped in fixture tack welds are used to keep each element in place and help reduce the stress. of each component.
What are the Advantages of Tack Welding
Tack Welding offers several benefits such as those listed below.
Benefits of Tack Welding:
- Tack Welding is relatively straightforward as there is very little need for fluxes or filler metal. Nor is there a large open flame.
- It doesn’t take an incredibly large amount of skill to learn tack welding.
Video credits to Redwingsteelworks. He demonstrates what he says is the right and wrong way to tack weld.
What are the disadvantages of Tack Welding?
There is usually both an upside and downside to performing a particular action. Tack welding is no exception to this. below are a few of the disadvantages of tack welding.
- The electrodes must be able to reach both sides of the metal being joined.
- Warpage can occur at the part where the weld is being done.
- The metal may be less resistant to corrosion.
Issues / Tips for troubleshooting tack welds
Many people think that tack welding is the easiest method of welding to learn. It isn’t. In fact, many people actually tack weld the wrong way, they just don’t know it. Many of the errors they perform on their welds don’t show at first. This is why many simply overlook the troubleshooting process when they do tack welds.
Below are 3 tips for troubleshooting your tack welds:
- Know whether you’re overusing your tack welds
- Knowing how to handle warpage
- Remeasure clamps
Tip 1. Are you overusing your welds?
People often worry about the amount of tack they’re using on their welds. This is why many welders refuse to use enough tack on their welds, they simply let the tack rest on the top of their welds rather than forcing them to penetrate the weld. This is the main reason why many welders welds aren’t relatively strong at all.
If you don’t use enough heat to fuse both of the pieces of metal then your weld won’t stay. In fact, if you make adequate use of your clamps and make sure to place your tacks in the correct spots, then you won’t have to worry about whether or not you’re tacking too much.
If you think of your tacks as simple, quick welds then you likely won’t be able to penetrate your metal thoroughly. Just as in a normal weld, tacking requires penetration in order to really work. To make sure you fully penetrate your metal, you can make sure to weld in either a u-shaped or circular motion – which ensures that your welds end up being even. Just make sure to reach the goal of welding, which is to make sure that your welds stick.
Tip 2. How to handle warpage
Much like freezing water, when you heat metal the molecules expand. When the metal cools it then contracts in a place completely different place. This is one of the main reasons why it’s such a pain to weld metal at 90 degree angles. The metal changes every single time you apply high levels of heat to it.
When you want to avoid the effects of warping, you typically think that performing quick tacks will get the job done. This can actually do much more harm than it does good. Instead of doing this it makes much more sense to pay attention to the place where you place your tacks. To make sure that your tacks are solid make sure that they are placed evenly around the metal.
Tip 3. Remeasure after you clamp
Many think that performing a tack on metal will take away the need for clamping, that’s not the case. When you clamp instead of tack you can avoid the warping issue that tacking can cause on a weld. The benefit of clamping is that it can take away the chances of warpage affecting the weld itself. If you don’t clamp the metal, then it’ll likely move around while you weld which will result in error.
Keep in mind that the clamps won’t completely eliminate the shifting that occurs during a weld. You should always make sure to measure each side after tacking to make sure that you can catch issues early. If you do, then you can apply methods which will allow you to fix the weld. If you don’t check your measurements after tacking, then you won’t be able to know whether or not you’re placing them in the correct place which can result in an incorrectly placed weld.
In short, if you want to make sure that you’re tacking correctly perform the above actions and makes sure you tack, this will result in adequate welds that perform to your satisfaction.
What makes tack welding important?
Although tack welding is temporary it is still just as important as the main weld. Tack welding is important because it does the below things for the weld:
- It makes sure pieces are aligned.
- It maintains the joint gap
- It contrasts and controls distortion and movement in welding
- Holds each piece in place
