Today we are going to answer the question: “How not to get pinholes in a weld?” I’m sure many welders are interested in finding out the answer to this question. Pinholes or sometimes called as “porosity” aren’t rare, in fact, a welder encounters it every now and then. This doesn’t mean that your skills as a welder aren’t top tier but it just means that you have to make a few adjustments or pay attention to a few things.
There are many causes of pinholes in welding, and one of the ways to get rid of them is to be aware of why they are there in the first place. Here are some common – not all – causes of pinholes that you should be aware about:
- Check your environment. In welding, we use a shielding gas right? To prevent the oxidization of the metal we are welding. The shielding gas protects the metal from the atmospheric air, specifically oxygen, so if the flow of the shielding gas is somehow disrupted, it can cause problems in your welding like the appearance of pinholes.
Before you begin welding, be sure to check the air ventilation in your welding area. Are there any strong breeze? Are you using a fan? Make sure that the air flow of the shielding gas is not disrupted.
- Check if the metal you are about to weld has moisture or dirt/rust/etc. Unknown to most, moisture in your metal can cause problems and so can rust. They can disrupt the welding process which is something that you don’t want to happen.
If you leave your metals outdoors, morning dew could form or it could get wet from the rain. You have two choices: (1) You can wipe it thoroughly – back to back, or (2) to make it easier for you, you can preheat the metal so that any moisture on the metal will easily evaporate.
- Check the amount and status of your welding gas. If your welding gas (or the shielding gas) is about to run out, or there’s something wrong with the mixture, this can cause pinholes.
- If the metal you are about to weld has oil, grease, dirt, or paint then you will need to take time to remove them thoroughly as they can get in the way of the welding process, and also the substances mentioned above let out dangerous or poisonous fumes when exposed to high temperatures.
Here is an image of a pinhole:
Look closely at where the finger is pointing to, that’s what a pinhole looks like. It doesn’t look great right? There are some cases wherein pinholes are intentionally created to be there. An example for this would be optics pin holes, which are used as apertures to select certain rays of light. This is used in pin hole cameras to form an images without the use of a lens. Sometimes, pin holes can also be found on produce packaging. The purpose behind this is to control the atmosphere and relieve the humidity within the packing.
Also before this article comes to a close, keep these general tips in mind:
- Always be aware of the proper arc length and maintain it. Sometimes the arc being too far away from the weld puddle can also be a cause of the appearance of pinholes.
- As I said above, cleanliness in welding is important. You should take time to clean the base metal you are going to be welding.
- You should also research on what the proper welding current is needed for a specific type of metal.
If you need more tips, you can browse around our website Welding Steel Tips and Tricks and also subscribe to us, that way we will be able to send you email alerts every time we post something new. Got a question? Feel free to drop a comment below or send us a message. We’d love to hear from you! Have a great day!