Magnetic Stainless Nails

w802h

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Jan 5, 2014
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I'm having a hard time sourcing stainless ring shank siding nails that are... stainless steel.  I've tried recent batches from Grip Rite/Prime Source and Swan Secure/Simpson but both are affected by magnets, a stainless coating only.  Does anyone have a source for good nails or has this product standard been universally lowered like so many others?  Thank goodness there's Festool. 
 
There are various grades of stainless steel and some are magnetic.  McFeeley's (https://www.mcfeelys.com)  is a great source of all things fastener and has explanations of types and uses for all.
 
Grip Rite has on their website that they make these nails out of 304 or 316 SS. Stainless steel can in fact be magnetic - if you have high quality stainless kitchen knives, Henckels for example they have SS blades that are martensitic which is very hard and holds an edge. You can check if your SS knives are similar wit a magnet - in this case magnetic SS is desired as it shows that they are not cheap. 304 and 316 are austenitic which is not normally magnetic, 304 can become somewhat magnetic under certain conditions - cold working is one of them.
 
If you stress certain austenitic stainless steels they can become magnetic too! Found that out when working in the Avionics industry, upset the magnetic safe distances of the electronics....

Get an austenitic piece of stainless and bend it to & fro and try holding a magnetic to it, you'll find it gets more magnetic as you bend it.
 
E30Mark said:
If you stress certain austenitic stainless steels they can become magnetic too! Found that out when working in the Avionics industry, upset the magnetic safe distances of the electronics....

Get an austenitic piece of stainless and bend it to & fro and try holding a magnetic to it, you'll find it gets more magnetic as you bend it.

You are correct - bending it to & fro is a form of cold working
 
I used Swan 316 ring shank split-less nails with maze heads ( made in USA ) on all cedar applications. They have a slight magnetic pull. If I remember correctly they are also rated for salt water environments.  or is that the 318's      MARK
 
E30Mark said:
If you stress certain austenitic stainless steels they can become magnetic too! Found that out when working in the Avionics industry, upset the magnetic safe distances of the electronics....

Get an austenitic piece of stainless and bend it to & fro and try holding a magnetic to it, you'll find it gets more magnetic as you bend it.

The cold working changes the crystal structure so it's not austentitic any more. It causes a phase transition to martensite which is magnetic.
 
andvari said:
E30Mark said:
If you stress certain austenitic stainless steels they can become magnetic too! Found that out when working in the Avionics industry, upset the magnetic safe distances of the electronics....

Get an austenitic piece of stainless and bend it to & fro and try holding a magnetic to it, you'll find it gets more magnetic as you bend it.

The cold working changes the crystal structure so it's not austentitic any more. It causes a phase transition to martensite which is magnetic.

Well, it took me some googling but I learned a lot from this post -

austentitic?

martensite?

I had never heard these terms before. And stuff like this is the *last* thing I'd expect to learn on a woodworking site.

The knowledge some of you guys have is amazing!

[not worthy] [not worthy] [not worthy]

 
I've learned something new, but maybe I'm even more confused.  Can someone explain why the nails I used to get weren't magnetic and now they are?  Would a different conveyor belt system cause cold working or is it more likely that the steel composition has changed?  I just want a good product.  I have heard of bad batches of stainless nails in the past that rusted.  I know of one builder that came back to the nail company with the cost of re-siding the whole house.  I'm trying to avoid a potential problem. 
 
I spoke with Swan today.  They explained how their material comes in and is tested before being used.  It is slightly magnetic due to the cold working and handling to make the nails, but he also told me that all stainless is not equal.  Some doesn't resist corrosion, some is more magnetic than others, etc.  Although he was confidant the nails were what they were supposed to be, he definitely wanted to make sure the product was correct.  I feel good using a US manufactured product with the raw material tested, rather than a company with global sourcing for product at the lowest possible price or multiple sources to fill a large order.
 
The corrosion resistance of Stainless Steel is related to the amount of Nickel and Chrome added to the alloy and since these metals are much more expensive then Iron you pay for the higher alloy mix.  316 should be the most corrosion resistant of the common types of stainless available.

Jack
 
My company just did a beach front job in South Carolina.  Stainless nails are expensive and like what other posts have pointed out the different grades of stainless steel.  I removed some cedar siding and was amazed to see the stainless nails were rusty.  We bought some from McFeelys.  I found a local lumber yard that did carry the nails and also gun nails to fit my nv65 coil siding nailer.  I believe that the gun nails were Hitachi.    If you are hand driving the nails it takes a very skilled hand being that the nails bend very easy.  I have some left over if interested i can give you a deal on if interested.    I have 8d 2 1/2 long.  If interested you can pm me. 
 
Some stainless shows "rust" from the iron crystals that are on the surface after forming. If they're passivated (bathed in acid post after forming) it prevents this.
 
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