Mill Scale Removal

[Nick DV]

I have some 3mm sheet steel that I got from work, but I'm having real trouble removing the mill scale for mig welding! On all the steel I've played with so far a 60 grit flap wheel has cleaned the steel back to bright shiny metal, but nothing other than a grinding wheel is touching the mill scale on the 3mm.

Can anyone help me here, and if I order some steel sheet in future, would it be better to get cold rolled steel instead of hot rolled?

TIA

 

[Welderpaul]

I have some 3mm sheet steel that I got from work, but I'm having real trouble removing the mill scale for mig welding! On all the steel I've played with so far a 60 grit flap wheel has cleaned the steel back to bright shiny metal, but nothing other than a grinding wheel is touching the mill scale on the 3mm.

Can anyone help me here, and if I order some steel sheet in future, would it be better to get cold rolled steel instead of hot rolled?

TIA

Shouldn't need to grind the millscale off for MIG.

 

[Bladevane]

Firstly, buy cold rolled for future jobs. Then for the current jobs use Muriatic acid (as our Murican colleagues call it), otherwise known as Hydrochloric acid - available as this https://www.toolstation.com/bostik-concentrated-mortar-brick-cleaner/p98902 (other brands are available).

 

[Rrobson]

Citric acid is supposedly good at removing scale

 

[Nick DV]

Shouldn't need to grind the millscale off for MIG.

Thanks Paul, I didn't realise that. Being fairly new to this, I thought the steel had to be really clean to get the best weld.

 

[Nick DV]

Firstly, buy cold rolled for future jobs. Then for the current jobs use Muriatic acid (as our Murican colleagues call it), otherwise known as Hydrochloric acid - available as this https://www.toolstation.com/bostik-concentrated-mortar-brick-cleaner/p98902 (other brands are available).

Thanks for that. I think this was mentioned on a Y/T video I've seen recently.

Citric acid is supposedly good at removing scale

Thanks, I'll bear that in mind too.

 

[Morrisman]

Shouldn't need to grind the millscale off for MIG.

If you have the power you can burn right through it, but if you are on the edge it really helps to get rid of it.

 

[Nick DV]

If you have the power you can burn right through it, but if you are on the edge it really helps to get rid of it.

Thanks, just like to make sure I do things properly