Welding of aluminium
Basic knowledge of aluminium welding
Aluminium is one of the light metals and can be welded relatively well using various welding processes. Problems with welding aluminium always occur when the necessary equipment or knowledge is not available. For both I will give you some information in this article or you will learn something about welding aluminium. At the end there is a very important video on the topic.
First important basis for welding aluminium: >>Aluminium can only be welded with alternating current in the TIG welding process<< The reason is simply that direct current does not break up the oxide layer. But what is necessary to weld the aluminium. I will come to the topic of oxide layer and the aluminium oxide later. An exception is MIG welding, especially the MIG process with pulse. Often very good results can be achieved, even with direct current. A big disadvantage is that acceptable results are only possible with very expensive HIGH END devices. Cheap devices, which for example have no pulse function, fail here. Or deliver results that are not acceptable. Since Mannis Welding Channel is designed for beginners and hobby welders, I will limit myself to the TIG process here.
Welding process for aluminium
TIG and MIG welding are suitable for welding aluminium. This also requires electrode welding, but this is not recommended.
TIG tungsten inert gas welding Is very well suited for welding aluminium if a few rules are observed. During TIG welding an arc burns between a non-melting tungsten electrode and a workpiece / component. The required filler metal is added separately by the welder. A particularly good welding result is achieved when pulsing with alternating current. If you are interested in TIG welding, I would like to recommend my free welding course. “Now I learn TIG welding”
MIG metal inert gas welding Practically the same as MAG or inert gas welding only with a different gas. An inert gas, usually argon or an argon mixture. Important here the pulse method is an advantage. In my experience, only more expensive MIG machines from EWM, for example, achieve good results. With such devices, the user can quickly reach several thousand Euros.
That is why my favourite for aluminium welding is TIG welding, also the possibilities and flexibility are very good.
Which welding machine
I have two favourites with whom I have had very good experience.
The first rather cheap machine is sufficient for the hobby or occasional welder and with 400-500 € rather cheap.
The second welding machine is an absolute professional device and also suitable for high demands. The device really leaves nothing to be desired and adjustment possibilities open. We are talking about an EWM Picotig 200 AC DC PULS TIG inverter welding machine. EWM is one of the leading manufacturers of welding equipment.
The biggest problem when welding aluminium is the aluminium oxide layer. Aluminium forms a thin layer of aluminium oxide on the surface with oxygen. The problem is that aluminium has a melting temperature of about 660°C. But this thin layer of aluminium oxide has a melting temperature of over 2000°C. So it is very difficult to melt this oxide layer and when you melt it down the base material has already received too much energy / heat.
>> So there is only one thing that helps to remove the aluminium oxide layer and that is best done by sanding. Best just before welding. Because the oxide layer immediately forms again.
Aluminium can be welded much better when it has a certain temperature, about 80 – 100 degrees. This is because aluminium is such a good heat conductor. If the material is too cold it simply conducts too much energy out of the weld. The preheating can be done with a torch, smaller parts can also be put into the oven.
Tips for welding aluminium
-Rounding off the tungsten electrode Normally the electrode is ground pointed, for aluminium the electrode must be ground rather round.
-Make sure the area around the weld is clean. It is best to clean the seam after grinding the oxide layer. Remove grinding dust and dirt.
-If the welding unit has a pulse function, then use it.