We have a full step by step guide on building homemade stick welder using microwave oven transformers (MOT). Welding is amazing and it is a great skill to have. Thus I want to share some important information with everyone to help save and good welding. So I have written this article as arc welding guide to help home welders and hobby welders. Arc welding requires a few important pieces of equipment, knowledge, and skill which I will explain.
First and the most important things is knowledge. Then we need a welding machine, protection gear like helmet, mask, gloves, etc. You can find them locally or you can buy them cheap at Amazon. After you have gathered all the equipment it is very important to have good and sound information about the process. Arc welding requires a constant arc to melt the filler rod and heat the base and joining metal. It needs the practice to become a skilled one.
At first, let me start by explaining the working mechanism of an arc welder. There are two types of arc welder available nowadays. Transformer powered welder and Inverter welder. In our project, we have made a transformer welder. It is cheap, traditional and we don’t need a deep knowledge of electronics. In Inverter welders, the electronics circuit provide required power so you need a good knowledge of electronics to build it.
How the Process Works
Welding machine takes input power through wall outlets of house or workplace that is 110v or 220v. The wall outlet has high voltage and fewer amps that will give the power (Wattage=Volts x Amps ). In an emergency case, you can use car batteries to weld too. Just put two or three 12 volt car batteries in series. Then use one terminal as an electrode holder and another to connect the ground clamp to the base metal.
A welding machine converts the high voltage low current to low voltage high current. The process may use a transformer or an electronic circuit. This makes it safe and suitable for welding. The two outputs are taken to create a short circuit to create a hot electrical arc to melt metal. One terminal is known as stinger or electrode and other is ground.
The welding output voltage of our homemade welder is 38 volts which run on 220V input. Many experts prefer 220V welder instead of 110V due to the good duty cycle. Another reason is the great built quality of transformers to handle 50 Hz electricity. So I advise people to make 220V welder even if they have a 110V wall outlet. You can use two sockets which are 180 degrees out of phase and put the primary of transformers in series.
Preparation for welding work
To have good weld we must be careful about the size of metal, electrode type, metal type, and settings. The welder should have good knowledge of electrodes and welding positions. Always use heavy-duty gloves, masks, cover, and shoes. The arc of welding is very bright and hot which can be hotter up to 2000 degree Celsius. UV Radiation is also emitted and it is pretty harmful to give you a burn.
Read More: Arc Welding Requirements
At first, let us know about the electrodes. There are various types of electrodes available and each has its own specialties. If you are a hobbyist and don’t tend to be so much technical and just do small and light fabrication, then 2.5mm E6013 electrode is the best. It is the most common rod used worldwide. It works on DC + or – and works on AC as well. The first two digits represent the tensile strength of the rod. 60 meaning 60 thousand PSI tensile strength.
E6013, E6010 and E6011 are other popular rods. These are also mostly used in welding pipes because they do good penetration. They can be used for good open root welding. E7014 is another rod that works on any current and it is told to be highly efficient. The common best and the strongest rod is E7018. Its low hydrogen property makes it good for weld and the slag cover is also less than E6013.
Starting the arc and keeping it up
First of all, these are some important things to always remember while welding.
1) Try not to weld Galvanized iron without a gas mask because the gas from zinc is carcinogenic.
2) Never ever touch two output leads at the same time.
3) Keep the welding area ventilated.
4) Be safe from any touch or connection with primary.
5) Install suitable fuse or circuit breaker for primary, I prefer an MCB switch.
The major problem for starters is to strike an arc. I also had this problem first, the rods would just stick to metal and the welder would make “hmm…” sound and heat up. You will have to lose the rod at that moment to be safe and protect the welder. People say that striking an arc is just like striking a match stick. Try to learn from some YouTube videos of other experts. After striking learn to maintain it and balance it and control the puddle.
The most important stuff is keeping the arc as short as possible. It is easy to balance and control when the arc is short. Try to push the puddle and slide away from the slag at the top because they can leave voids and puddles. If you have a welder with current control then it is obvious that you should keep low current for thin metals and high for thick ones. The saying is that when the current is right the weld sounds like “Bacon Fry”. Just keep on practicing to improve your skills.