# 1 vessel build polishing SS



## rude (17/5/17)

I have been prepping my keggle for the above

At the bottom of keggle there is an outside skin welded to sit the keg on

I wanted to grind a bit of this away to drill holes for return wirlpool , outlet to the pump & heating element
so they were closer to the bottom

I did 2 of the areas where I'm going to drill but noticed the heat has gone through to the inside of the keg
discolouring it

Can I use a paste & pad to polish this out ?

If so what paste pad do I need & where can I buy some

Cheers Rude


----------



## klangers (17/5/17)

Super cheap auto has enough metal polishing tools and consumables to choose the right one from. Can't tell you off the top of my head sorry.

In saying that, it sounds like the heat affected area of the weld. In this case it may have to be pickled instead. This involves applying pickling paste which re-passivates the weld and dissolves away the oxides which cause the discolourisation. Be careful though, pickling paste is evil - contains hydrofluoric and sulphuric acids.


----------



## rude (17/5/17)

Quick reply cheers

No weld inside just the heat came through so will try Auto cheap 

Thanks


----------



## TwoCrows (17/5/17)

Use a pot scrubber to polish it out.


----------



## Feldon (17/5/17)

Bar Keepers Friend will remove the blueing and re-passivate the surface (can get it a Coles nowadays). If you just buff it out the blueing might return.

Or buff it out then passivate with citric acid and water, or lemon juice.

Wear gloves, and safety glasses in case you flick some in your eyes.

(Avoid steel wool and stainless steel wool, or anything with iron in it. Will just make it worse)


----------



## TwoCrows (17/5/17)

SS will self passivate. You just need to remove contaminates on the surface that prevent an oxide film to become present.

Using a pickle or acid is used to help remove surface contaminants.


----------



## rude (17/5/17)

Ended up buying autosol cleaner & polish from Bunnnings

It removed the heat mark nicely then hosed off but you can tell where the polish was

Might give it a spry with star san then use a sodium perc mix to clean ???


----------



## Feldon (17/5/17)

I think the OP was saying that it wasn't contaminates on the inner surface that caused the discolouration or blueing. It was heat applied from the outside. The heat has stuffed up the arrangement of atoms in the stainless steel. Re-passivating with an acid this will cause the chromium atoms to realign on the surface and point their shiny faces to the sky.


----------



## rude (17/5/17)

Correct dis colouring from grinding the outside


----------

