question about power settings / material thickness

[marada]

I have the Clarke 160TM mig welder and have used the online hobby mig welding calculator. The power settings state the following

power setting 1: 0.9 to 1.1 mm
power setting 2: 1.1 to 1.5 mm
power setting 3: 1.6 to 2.0 mm
power setting 4: 2.1 to 2.6 mm
power stting 5: 2.7 to 3.5 mm
power setting 6: 3.4 to 4.3 mm

My question is are these settings applied to the total thickness of the 2 materials being welded together? As an example if I am welding car body panels of say 1.5mm thick together, then 2 of these would equal a total thickness of 3mm. As a guide does this mean I would use power setting 5 as this specifies 2.7 to 3.5mm, or would I go on the individual piece thickness and use power setting 2 as this specifies 1.1 to 1.5mm?

Also what power setting should I use if I am welding different thickness material such as 3mm box to a car body panel? Or say welding a solid bolt to a car body panel (for making up a bracket)
I know these are guides only, but I am really new to this so would appreciate a rough idea.

 

[Chickenjohn]

I have a Clarke 150 Turbo which should be simmilar to your welder. The best thing you can do is not consider these figures in the manual as gospel. Get hold of some scrap steel (clean!) of various thickness and try with the different settings.

By the way, these figures referr to butt welding two pieces together, so if two pieces of 0.9mm, then use setting 1. Not set in stone though as factors such as distance of welding nozzle from work piece and the speed you move the weld bead at all make a difference. And also the wire speed as well.

As a rough guide, assuming your welder is simmilar to mine on each setting, then I do this:-

Thin car panels (wing repairs etc), setting 1.
Inner wings setting 2.
Sills and chassis , 3 or 4.
Plug welds, 3 or 4.

I rarely need the higher settings as I almost never weld anything thicker than 2 or 3mm.

Have a go on different gauges of steel as your technique also makes a difference.

 

[marada]

Thanks for your reply but is it the combined thickness of the metal? What would you select if you say wanted to weld a solid bolt to car panels?

 

[malcolm]

The calculator on this site assumes you are butt welding two sheets of steel of identical thickness together with a continuous weld. For that the thickness is that of the sheet (no adding together).

If you were overlapping then the combined thickness on one side of the weld would be thicker. In that case a starting point might be somewhere between the thickness of the steel and double the thickness.

A bolt would heat up quickly and complicate things (takes less power to weld hot things). At a guess go at least 2/3 towards the thinner thickness, maybe a notch but no more than two up from where you would be if you were welding that thickness sheet.

Also if you were welding into an angle you might go for the same power (voltage) setting as butt welding, but increase the wire speed a little.

The calculator is only a starting point to get people started. Once you get going use your own judgement. The appearance of the weld is what I use for my hobby work - if it's standing tall it's worth trying another notch on the power, if the wire is burning back then a bit more wire speed should help.