When mig welding sheet metal it is important to set the proper parameters to prevent warping and burn through or else it will create excess heat and easily blowholes on the metal.
Blowing holes in 20 ga sheet metal with my mig.
The biggest mistake a welder can make is to blow a hole in the panel.
I also want to fix some small holes in my door but i am so afraid to make a mess or blow through the hole.
The aim with this technique is to melt a bit of metal and then let it cool slightly before melting the next and it s a handy way to avoid blowing holes.
Mig welding sheet metal.
For thinner gauge sheet metal like 18 or 20 gauge we suggest 023 6mm wire in your mig welder.
Keep in mind during the welding process it is important to direct the arc right at the center of the weld puddle and don t do movements like whipping or weaving as it may cause warping and burn through quickly.
If you are butt welding try to minimise the gap between the two sheets.
The thin metal technique is a non continuous process that is used for thin metal such as car body panels.
I got a bunch of holes to weld up on my rear frames rails on my 68 mustang are thin gauge soda can style.
The most obvious advice for a mig welder is to use the smallest wire diameter as possible.
If the parts fail to touch each other for even 1 16 inch you have created a hole that invites burn through and a gap that can t absorb the heat.
Imagine a butt weld on 20 to 24 gauge metal.
Im replacing quarter panels on my car and have been practicing butt welding on the old panels.
I have been having problems with burning holes through the metal i have tried to weld for a second then stop then weld it works to a point and sometimes i get a nice weld but usually i burn a hole in the metal also i been stitch welding the metal and it is still warping in.
Either way there are certain things that a welder needs to be aware of when mig welding sheet metal.
If your welding wire is too thick it will take more heat to melt the wire than the substrate and can make it even more prone to blowing holes in the panel.
If after you hit the trigger and the arc is established you start to blow a hole or the surrounding metal starts to melt too fast let off the trigger.
If you start right at the edge where you really want the weld to be you will likely burn the edge and blow it away before the bottom base metal ever gets molten.
I have welded holes using a copper spoon backer but these holes i am unable to use a copper backer.
This can happen due to inexperience or because turning the heat up too high.
Reducing the power and wire speed might help although the metal needs to be completely shiny and clean for low power stuff to work at all.
