Polishing Stainless

[Chris]

I recently cut of a pair of brackets that were welded to my Aframe and it has left some unsightly grinding marks where I used a grinder to do the work. Is is possible to get rid of these marks and what is the best method?

Thanks

Chris

[Jizm]

Originally Posted by Chris1573

I recently cut of a pair of brackets that were welded to my Aframe and it has left some unsightly grinding marks where I used a grinder to do the work. Is is possible to get rid of these marks and what is the best method?

Thanks

Chris

Fine emery paper followed by a buffing wheel with polishing soap.

[Nos4r2]

There's a really good stainless polisher in Stonehouse. I'll try and find his name.

[Sixy_the_red]

You can do it yourself, but its a very long, very messy job. I'd pay someone to do it for you.

[martini]

A mini angle grinder with sanding discs or similar to start. If you've used a grinding disc then you will prob have to start with around 40 or 60 grit, a flap disc would also work. Then go up through the stages, 120,240 etc to about 300-400 grit. Then you need a coarse polishing soap like Supercut 40 on a sponge or similar compounding mop. Then you can use something like autosol just to bring up the shine and finish it off.

It needs to be spot on mirror finish if you don't want it rusting.

At work we get all our polishing supplies from here.
Their site is worth a good look, they have some handy guides etc to help you with polishing metals.
Edit - website is having an upgrade, polishing guides not there anymore
METHOD No. 2 - pay someone else!

[Hightower]

I thought that Stainless Steel fabricators get their work chemical dipped for a highly polished finish?

[martini]

Originally Posted by Hightower

I thought that Stainless Steel fabricators get their work chemical dipped for a highly polished finish?

Larger companies may dip their work in 'passivating' chemicals which remove oxide scaling, burn marks and annealing discolouring (yellow/purple bits next to weld). It also restores the chromium oxide layer covering the stainless which is the stuff that makes it corrosion resistant.

It gives a clean look but doesn't actually polish nor unfortunately does it get rid of dodgy grinding marks!

I have seen a process where the job (usually smallish items) are put in a tank full of tiny plastic abrasive balls and the tank is agitated for a couple of hours. It comes out with a perfect mirror finish but it's the kind of thing thats more the reserve of the mass production industries, can't see my boss forking out that kind of ££££ just to make my life easier!

[Jizm]

Originally Posted by Hightower

I thought that Stainless Steel fabricators get their work chemical dipped for a highly polished finish?

I have seen some fabricators brush 'pickling paste' onto their weld, brings it proper, gets rid of the discolouration.

[Hightower]

Originally Posted by Jizm

I have seen some fabricators brush 'pickling paste' onto their weld, brings it proper, gets rid of the discolouration.

I've got some here, some kind gent on RIBnet sent some to me.

[Jono]

Originally Posted by Jizm

I have seen some fabricators brush 'pickling paste' onto their weld, brings it proper, gets rid of the discolouration.

....but it doesn't "polish" the surface.

[Sixy_the_red]

I've also heard of a process called 'Vapour blasting'. Similar to sand blasting but apparently acheives a polished finish, although I believe it leaves the surface porous so has to be lacquered before it can be handled. (I was enquiring about it for cast aluminium though, so I don't know whether the same would apply for SS)

[Simon B]

We had a mob in to do some cryo-genic blasting, very impressive, they use chipped solid carbon dioxide then wazz it through a blasting gun alegedly at supersonic speed. Very noisy but did bring our flavour drum up a treat. Not cheap either.