# Stainless steel - what grade?



## disco_monkey79 (3 Jul 2017)

Hi

I want to make some decorative pieces that will be permanently outdoors. I want a high-shine finish. What grade of stainless steel would be best?

Or is the shininess more to do with how the metal is finished, than the grade of steel? 

Thanks


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## Cordy (3 Jul 2017)

My old mate was a stainless steel welder

He reckoned a good test was with a small magnet - if the S/Steel was non-magnetic it was good
If it is magnetic it might not be good outside; especially in a marine environment

Some reading for you

Hope that helps


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## Phil Pascoe (3 Jul 2017)

Permanently outside where? A4 (sae 316) is marine grade and would probably be wise if you're on the coast.
(I've never understood why people are reluctant to give any clue of their location :? )


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## porker (3 Jul 2017)

I would also go with 316 if corrosion resistance is main priority. One thing to consider is what machining processes you need to make. Different grades machine differently (they are all quite hard). Also some weld better than others.

Sent from my SM-G920F using Tapatalk


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## disco_monkey79 (3 Jul 2017)

Thanks all. The idea is to use it for brightwork on a truck instead of chrome or polished aluminium. Sounds like 316 is going to give the most longevity. 

Re location - as it's a truck, it'll be all over the place


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## Gerry (3 Jul 2017)

My Sidebars on my Shogun sport are 304 stainless.
Still nice and bright after 2 years of neglect.

Gerry


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## disco_monkey79 (3 Jul 2017)

Thanks. The ability to withstand neglect is what I'm after - can't summon the enthusiasm to polish the wheels


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## sunnybob (3 Jul 2017)

I take it youre talking about wheel embellishments? sounds silly but sometimes you have to ask the silly question. if the stainless is going to be under stress thats a whole different ball game and you would need specialist advice.


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## sunnybob (3 Jul 2017)

phil.p":3ppxsipn said:


> Permanently outside where? A4 (sae 316) is marine grade and would probably be wise if you're on the coast.
> (I've never understood why people are reluctant to give any clue of their location :? )



Phil, your own address allows for some confusion, even though you do mention the county in a roundabout way (lol)


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## Mike Jordan (3 Jul 2017)

I don't know a great amount about stainless steels but I have learnt that 316 is very hard to work, drill, and bend, 304 is much easier to use. If weight is a consideration then there is plenty of stainless tubing which looks just as good and is obviously much lighter? The material I have used has been described as either self colour or polished. Polished has been best for my use since it has been a substitute for polished brass bar.


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## disco_monkey79 (3 Jul 2017)

Hiya

Thanks all for the replies. The brightwork will be purely decorative on the bodywork. I only mentioned the wheels as proof of my being too bone-idle to polish anything.

Interesting to hear that 304 is much easier to work. I bought some stainless box section (type unknown) for an unrelated job and it was hard as hell.


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## Phil Pascoe (3 Jul 2017)

sunnybob":2r9a30jo said:


> phil.p":2r9a30jo said:
> 
> 
> > Permanently outside where? A4 (sae 316) is marine grade and would probably be wise if you're on the coast.
> ...



It shows I'm not in Aberdeen or Central London. No one needs know the number of your house.


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## sunnybob (3 Jul 2017)

All stainless is hard to work. If you are drilling, the secret is drill SLOWLY and not too much pressure. A fast drill speed and leaning on the drill will burn the bit in seconds.


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## porker (3 Jul 2017)

sunnybob":2x3qqpj4 said:


> All stainless is hard to work. If you are drilling, the secret is drill SLOWLY and not too much pressure. A fast drill speed and leaning on the drill will burn the bit in seconds.



+1 If you let the drill rub it will work harden and then it is a real pain. Use a bit of cutting oil too if you have it.


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## MusicMan (3 Jul 2017)

The key to the corrosion resistance of stainless steel is the chromium content, usually over 18%, though some can be replaced by other elements. This makes a fully covering skin of chromic oxide, which is what resists the corrosion.

The magnetic/non magnetic issue is different and not related to the corrodability. The nickel content gives a structural change to the so-called "austenitic" form, which, is relatively malleable hence can be stamped or spun without cracking. Magnetic forms, ("ferritic") with less nickel but with other elements e.g. molybdenum, are generally hardenable, so more suitable for tooling and high wear resistance. 

So choose the stainless steel for how you want to work it. They'll all be corrosion resistant (with some differences in a marine environment but not huge for decorative pieces, and buff them up well.

Yes they all work harden as has been said, so use sharp tools and go steadily, without rubbing or rushing.


Keith
(PhD in metallurgy a long time ago, spent this afternoon machining stainless steel; 4 hours to drill a 3/4" hole 3" deep.)


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## sunnybob (4 Jul 2017)

The Cyprus local council of famagusta, which covers the really big tourist towns of agia napa and pernera and protaras, made a beach side walk a few years ago, with concrete and or board paths, and stainless steel railings that go on for miles.
Yes, i think youve guessed it. They cheapskated on the stainless and now there are miles of slightly brown tubular railings that look so bad you dont really want to put your hands on them.
I expect the contractor was a close relative of the mayor.


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## TFrench (4 Jul 2017)

If its sheet stainless you want, get 304 BA (bright annealed) - looks just like chrome. We use it for food factory insulation cladding. You can get it in thicknesses down to 0.5mm (used to be able to get 0.4, it was lovely to work with!) and it works fairly easily. Just mind the sharp edges!


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## Phil Pascoe (4 Jul 2017)

My friend's daughter has an engineering apprenticeship at an extremely upmarket boat builders. She told him one day that a woman had had the hand rails on her new yacht changed ... because she decided she didn't like the colour any more - £90,000s worth of hand rails.


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## sunnybob (5 Jul 2017)

There was a film about a huge gold robbery. he hid the gold by making guard rails for his yacht out of it and every body thought it was brass. maybe thats what the woman was doing, smuggling it across the channel


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## Keith 66 (6 Jul 2017)

I have used several grades on boats, Ordinary 304 (A2) will show surface discoloration quite quickly & need polishing often. 316 (A4) will polish up & stay bright for ages.
The secret of drilling stainless is sharp drills, slow speed & firm feed pressure with plenty of cutting oil.


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## oakmitre (6 Jul 2017)

Small decorative pieces - how small ? 

Would it be possible to make these from already finished articles ? You can get shiny SS thin plate cheaply from places such as the range / b&ms or large roasting tins from Ikea.

You can also buy thin flypress cut disc from ebay that are already mirror finished.,

If you buy a piece of flat bar from your local steel supplier it will shine up , but to get rid of the 'pock marks' in the surface is very difficult. I've done this with a zirconium belt and it heats up very quickly and is very time consuming.


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## Hitch (7 Jul 2017)

If its decorative, on a decent truck, go with 316, if its a working truck and not wanting to look perfect forever, go with 304.

I do a fair bit of stainless work. Bright annealed 316 would be a nice choice, and easy to polish up just taht little bit more...if you really want bright, try and get hold of some mirror polished sheet.


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