Stainless steel contamination via tools

[hunter27]

Hi All
I was tigging stainless steel bits together today and was thinking. I keep dedicated stainless wire brushes and flap disks for use with stainless steel but what about hacksaw blades, files, etc if they have not been used on mild steel are they alright ?

Thanks
Pete

 

[TechnicAl]

As long as you keep them seperate. Its Iron that contaminates the SS.

If you passivate the surface when youve finished it should show up any iron contamination.......stains or rusts

 

[Richard.]

For aluminium I keep my abrasives separate to avoid cross contamination. I've never bothered with stainless. I'm not sure how important that is really. I'd imagine the likes of Tig Paul who works with it day in day out May keep abrasives for steel and stainless separate. I don't do enough to worry about it. With aluminium it's a must as it welds terrible if there is the slightest contaminant in the pool.

 

[Kent]

Gosh it was a long while back now but I did a course on stainless and the instructor he even mentioned contamination guillotine blades. Stainless work at these levels requires a separate shop IMO. Back in the 80s there was a big SS boom in fab shops as the catering trade made more compulsory switches by the early 90s it was all over as too many "specialist firms" set up for a slice of that pie. It depends on were its going and the spec., I had to sit the course for a certain contract that I cant remember now but there was some real rubbish being produced at the time and I recon it was likely asked for just to cut the cowboys out

 

[hunter27]

Thanks for the replies I made a fish ornament in 304 stainless rod for in the bathroom but small bits where I have used tools on it show small rust speckles on it, it cleans of easily but does come back eventually. I am more concerned with any bits I may make for my boat.
Pete

 

[Kent]

Thanks for the replies I made a fish ornament in 304 stainless rod for in the bathroom but small bits where I have used tools on it show small rust speckles on it, it cleans of easily but does come back eventually. I am more concerned with any bits I may make for my boat.
Pete

Some grades will show more rust staining - look at knives from the dishwasher for confirmation.

 

[hotrodder]

Knives are normally a martensitic flavour of stainless and far less corrosion resistant than the austenitic 3xx series. Personally i don't bother with seperate saw blades/files etc, just abrasives. If the application makes corrosion resistance a real issue then deburring cut/filed edges with abrasives or proper deburring tools should deal with any cross contamination there... i'm more bothered about say nicking the laserguard/plastic protection when sliding a sheet into a guillotine than contamination from the blade itself for example

Try simmering your fish ornament in citric acid for 20 minutes or so, that could permantly deal with any light stains. Oxalic acid should be better at etching out iron as long as it's not deeply embedded/there's lots of it and like citric is cheap and safe compared to more aggressive acids like pickling pastes

 

[hunter27]

Knives are normally a martensitic flavour of stainless and far less corrosion resistant than the austenitic 3xx series. Personally i don't bother with seperate saw blades/files etc, just abrasives. If the application makes corrosion resistance a real issue then deburring cut/filed edges with abrasives or proper deburring tools should deal with any cross contamination there... i'm more bothered about say nicking the laserguard/plastic protection when sliding a sheet into a guillotine than contamination from the blade itself for example

Try simmering your fish ornament in citric acid for 20 minutes or so, that could permantly deal with any light stains. Oxalic acid should be better at etching out iron as long as it's not deeply embedded/there's lots of it and like citric is cheap and safe compared to more aggressive acids like pickling pastes

Thanks I will give the oxalic acid a go I have some in the garage.
Pete

 

[Shox Dr]

One of the biggest risks is grinding sparks, embedding in the SS, if close enough even through the protection film. We had built a load of canopies and was on with some frame work in steel, I'd MIG'd it all up, and left a labourer linshing the welds, firing the sparks towards the SS canopies, came in the next day they were covered in rust.