MIG welding or Stick welding?

So you want to try your hand at welding but are unsure which way to go...the 2 types of welding are quite different.

An over view of the weld process...........

Welding is simply joining 2 pieces of metal together by heating them up and introducing a filler metal into the weld joint. Then you move along the joint for the desired length of weld.

Now the big bad enemy of welding is Oxygen.  When you heat up the joint and start to add your filler metal, Oxygen tries to get into the joint and muck it up. Any molten metal will start to oxidize if it comes into contact with our friend "Oxygen". The joint then becomes similar to look at as a sponge with lots of holes running through it. The joint is weak and no good.

The whole idea when welding is to keep oxygen away from the molten pool until it has cooled and turned back into a solid state.

The MIG welding process is named (Metal Inert Gas). This is the process whereby an inert gas is piped over and around the molten weld pool by a special torch. The filler wire in the MIG process is usually housed in the main welding machine some way from the weld joint. There is a special liner tube which runs down the centre of the mig torch and discharges through a nozzle in the end of the torch. The inert gas is fed down a tube inside the torch from a bottle usually with the main welder.

This gas is then fed through the torch and exits around the nozzle right at the welding joint end.The gas then flows over and around the weld and stops the oxygen getting at the molten joint while it solidifies.

 typical mig torch image


The STICK welding process is a different way of keeping oxygen out of the joint. The filler material is in the guise of a welding electrode which is coated with a flux material. When the welding rod is used in the process, the filler material melts off the end of the rod and at the same time all the heat produced causes the flux to melt all over the molten metal.

This flux is specially designed for each type of welding rod and for each type of metal being welded.

 Electrode image


So to sum up then....

MIG is usually a fairly large heavy machine in a fabrication shop or a small portable type for a hobbyist.

The larger machines are usually 3 phase 440v and can lay down quite a bit weld in one go.The parent metal has to be clean and free of rust or paint. The larger machines are ideal for thick materials where as the smaller portable ones are more suited to welding up sheet metal and car bodies.

STICK welders range from small 240v or 110v portable machines which are mostly inverter type welders these days. The size range can vary from 130A output up to about 300-400A on the more industrial ones. There are still a few big old heavy oil cooled welders like the old Oxford but most are now the light weight inverters weighing up to about 5kg.

These type of welders are ideal for small workshop repairs to plant and machinery and would be quite hard to use on car body work.

They don't mind a small amount of rust or paint either.


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