You are on the self-taught welding channel.
I will give some tips for welding with an inverter in everyday life - in a garage, at home, in a summer cottage. Namely, which electrodes are better to buy if you have to weld a structure made of thick metal.
Let's conventionally consider thickness from 4 mm under thick metal. I think that for our everyday needs this will already be a serious thickness. And on such metal, even completely beginners, there should not be frequent burn-throughs.
Electrodes are classified according to the type of coating on the metal rod. There are basic coated, rutile coated, and rutile cellulosic coated.
Let's break it down with clear practical examples.
If we weld structures from a profile pipe, we mainly buy a thin-walled pipe 1.5-2 mm thick for everyday life. For these works, it is better to purchase electrodes with a rutile or rutile cellulose coating.
These are the electrodes brands
ANO-21
MR 3
OK-46
MONOLITH
The good thing about these electrodes is that they are easy to cook with frequent pull-off. For a thin professional pipe, this is very convenient so as not to make frequent burns. Also, these electrodes are not particularly picky about the surface to be welded - they will ignite well both on rusty and dirty pieces of metal. But it's still better to try to make the surface clean before welding.
Now we come to our main topic of the article. But if you need to weld a structure made of thick metal.
This is a homemade drawbar in the photo for a beekeeper's booth. It is not basic, but auxiliary and removable. Located at the back of the booth, you need to make a U-turn on a narrow street.
Similar and other thick metal structures imply some kind of load. That means they must be tightly assembled, welded. That is, the welding seam itself must be strong and not break from stress.
These are basic coated electrodes. The most optimal in terms of price and quality are domestic electrodes SONI 13 55.
In the photo above on the left, Japanese LB 52U electrodes are also excellent electrodes, even better than SSSI, but only much more expensive. For a home, a summer residence will be a bit fat!
Basic electrodes have an excellent strong seam, the pool is clearly visible during the welding process. There is no such slagging as with rutile coated electrodes. But there are also disadvantages, a beginner should know them, well, as disadvantages, certain difficulties at the beginning of working with them.
They need to be welded with a continuous seam, lit and driven to cook without interruption. With a frequent separation it will be problematic, it may simply not ignite again. We'll have to spend time firing up.
The metal surface for welding with these electrodes must be well cleaned. If welded on a dirty, rusty surface, it will also be problematic. The arc may be extinguished and normal welding may not work.
SSSI is cooked only on direct current of reverse polarity. This means that the holder with the electrode is connected to the plus of the welding inverter, the mass, respectively, to the minus.
These electrodes need to be acclimated to. But then welding with them will be simple, and the result is excellent. Try it, take a small pack of such electrodes for training.
Make an experiment like this. Take two identical pieces of iron and grab them to the third piece of iron. Grab one with rutile electrodes, and the second with SSSI. And just break off these grabbed pieces of iron, or beat off with a hammer. You will immediately understand where the seam metal is stronger and more ductile.