Category Archives: Why Is There Pinholes In The Weld Sometimes

Why Is There Pinholes In The Weld Sometimes

Sometimes, welders will notice that there are pinholes in their welds, and find themselves asking why is this so. Pinholes are sometimes unavoidable, but they can be prevented. This doesn’t mean that the welder isn’t skilled enough, sometimes, it just happens because of a lot of factors. Pinholes are sometimes referred to as “porosity”. They are considered as a welding defect. Let’s be honest, seeing little holes in your finished product is never a good thing. As I said above, there’s a lot of reason behind the appearance of pinholes. Don’t worry, you will be able to fix pinholes so relax.


The most common cause of pinholes if the unbalanced temperature, in other words, it’s too hot. High welding temperatures can cause pinholes to appear. If the temperature od the arc is making the weld is too high, tiny holes will start to appear at the surface of the weld. This is because there is “trapped gas” in the weld. It’s not considered as a serious defect though.

It could also be that the cylinder you are using is out of gas, so be sure to check that. You should also watch out for the ventilation direction, because of some kind of air or draft is disturbing the delivery of the shielding gas while you are welding, then it can cause these annoying tiny bubbles to appear. As a welder, you have to be aware of open doors and air flow, even those air flow that is being emitted from the machinery that you are using.


The presence of moisture can also lead to pinholes. This is because of the process of condensation from welding on a heavy plate or lap joint, which then can cause temperatures to reach below 50 degrees Fahrenheit. A quick solution to this would be to always preheat the metal to at least 200 to 220 F to be able to get rid of the moisture.


Before yo begin welding, also check the gas hose it it’s pinched or if something is blocking it. It won’t be able to deliver the shielding gas properly, which we have learned from above can cause pinholes to appear. If you have done all these, but still there are pinholes appearing on your weld, it may be time to call on sometime to check if the gas is contaminated or not. If there’s a cut or a burn in your hose, that can also cause problems.


There are many reasons as to why pinholes sometimes appear on your weld, but it’s easy to prevent them. You just have to be aware of what you are doing and of your materials. If you have any questions, feel free to send us a message or leave a comment below. We’d love to accommodate you and answer your questions! See you!