Greetings to all self-taught beginners in manual arc welding. And also lovers of working with metal at home, garage, summer cottage. Our channel gives answers to questions that all beginners in welding and locksmith must have.
Each article covers one question, and sometimes several. Today we'll talk about an important topic - if you need to weld a thin and thick piece of iron, how do we set the welding current correctly, on a thin or thick part?
The two photos above are details with very different thicknesses. A plate with a thickness of only 1 mm and a piece of metal as much as 15 mm thick, that's the difference. We need this experiment as an example of such welding, in reality, welding of 1 mm to 15 mm is rarely required.
We will cook with an electrode with a diameter of 3 mm - the most common diameter in household welding. Although it is best to have several electrode diameters in stock - 2mm, 2.5mm, 3mm, it will be easier to solve any welding issue.
Or here's a couple of old photos from our channel. This is an example of welding a piece of tin and a piece of a channel.
So, we will set the welding current only for thicker metal. Normal amperage will allow the metal to melt well and the seam will be correct.
For a thinner metal, this current is too large, but we compensate for this with the correct welding technique, then you will see everything.
So, for our task, we have selected the optimal current for a thicker piece of iron. No one will definitely advise the correct amperage for your tasks, the current is selected individually in each case. Plus, each welding inverter cooks differently.
So I will give a universal advice for a beginner on setting the current. Slowly slide the electrode over the piece of iron. The molten track behind the tip of the electrode should be about 2-2.5 times the diameter of the electrode. Visually determine, changing the current, so that the fiery path becomes 2 times thicker than the electrode.
These 2 pictures above are a sectional weld seam. For the lower position, the seam is fused into the metal in the form of an inverted mushroom cap! In the center, the penetration depth is the greatest, there was the maximum energy from the electrode. The farther from the center to the edges, the lower the penetration depth, and hence the energy from the electrode.
What will it give us? Thin metal must be cooked at a lower current than thick one. And the current is tuned to thick metal. This means that when welding, we need to touch thin metal only with the edge of the weld pool from a thick one, so as not to give it a lot of energy, not to burn through but weld with a thick one.
We weld this way, we cook these pieces of iron by directing the welding arc mainly to the thick part. We make small oscillatory movements or without them, as who will adapt. And when welding, we will touch the thin metal only slightly, with the edge of the weld pool. So we will not burn but weld.
That's all, we welded our blanks. When welding a can and a channel, there are places with burn-throughs, but this was an experiment to visualize the topic. In real life, we don't need this complexity.
When we weld thin to thick, what part of the welding arc should we direct to thin metal? You need to try, experiment, so as not to burn through and weld normally without slagging.
With today's article, I wanted to show you self-taught beginners, the very principle of such welding. Now it's up to training to gain experience.