Anti rust treatment time. Do welds cause salts to develop ?

[Weldinator]

Hi noob here ,

I have recently been advised that salts are produced during the weld process, does anyone know if this is true and is it best to always grind the weld area well to tidy it up if it does happen ?

Cheers

 

[TechnicAl]

salts?

you get oxides but salts...........what do you mean?

 

[the snooper]

i wonder if someone is refering to the slag left behind after arc welding
seems a little strange someone would tell him that

 

[R Kraft]

It could be that the arc welding burns the oils and coatings off of the metal.
That could causes it to look like salts have been working on it.
Robert

 

[PTvor]

Which welding process and what are these salts supposed to be?

Arc welding mild steel, there's a slag to chip off which seems insoluble in water. There's sometimes a light dusting from the arc. I haven't noticed a difference in the tendency to rust between cleaned off mild steel and cleaned off mild steel with weld. They both rust pretty quickly left outside in the damp.

If you want to stop mild steel from rusting, welded or not, you have to prepare it and cover it with something such as primer and paint. Preparing, doesn't necessarily mean grinding back the weld.

 

[Weldinator]

I think what was meant is there are surface salts produced which in time cause the welds to start rusting underneath the primer, they cant be seen they are a chemical contaminant that the weld causes. Im no metal specialist but the way i see it is the metal is made from iron ore which is a rock substance which in turn has made the sea salty, rock becomes salt .

I am asking because before i primer the areas of my project i want it to last a very long time .


Oh and i mig weld but i think its caused by any type of molten metal welding.

Cheers.

 

[Wozzaaah]

This thread has a hint of trolling about it but I'll give you the benefit of the doubt.

It's not Iron ore which has made the sea salty, it's sodium chloride, otherwise known as .......errrrr.......ummmm........salt!

If you take your time degreasing and cleaning the welds and surrounding metal prior to painting and paint it properly (i.e with the correct paint) then there's no reason why it shouldn't last for a very long time.

Why on earth is this in the machines section too? Paint and metal coatings dear boy! I'll move it for you.

 

[Weldinator]

Its a welding question that is why.

Rocks are still the cause of salt is it not ?

 

[Wozzaaah]

It's not a machine question though, 'welders and welding machines' is about machine-related queries. Yours is about protecting metal from rusting so it's now where it ought to be.
Sodium chloride is the cause of salt, it's the same stuff you douse your dinner in every night.

I honestly reckon you're thinking too much about this, as I said, weld it, clean it, paint it...job done.

 

[pedrobedro]

Sodium chloride doesn't cause salt, it is the chemical formula or the chemical name of the salt used for cooking etc. Impurities may cause mineral salts to be formed when welding and there are also some present in flux but they shouldn't be a problem if you clean and prime before painting as above. If you don't need to disguise the weld why grind it?

 

[Weldinator]

Thanks, i will be grinding them for neatness no matter where they are so when i apply the sealant it will go on smoother, so water wont get behind it get trapped and then start rusting again.

That's the kind of thing i was thinking about with it making minerals etc, its been a while since i did any science .