Using 430 Stainless Steel for Neve enclosure

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vdr20

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Joined
Dec 30, 2016
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Has anyone tried making an enclosure out of 430 stainless steel? How does it compare to mild steel in terms of EMI shielding etc.? I'm assuming that it would be extremely similar in performance to mild steel with the added advantage of corrosion resistance but I have my doubts since otherwise, it would have been used more often in production units where it seems like galvanized steel is more favourable.

Is it's difficulty in working the material the reason why it's not often used?

 
I think Neve used nickel plated steel. If you want to retain the magnetic screening properties of steel but also be corrosion resistant you could use galvanised steel.

Cheers

Ian
 
430 stainless steel is magnetic. 300 series stainless steel is non-magnetic I believe. I’m just not sure by how much it’s shielding abilities are comparable to that of mild steel.

I don’t really like the look of galvanised steel.
 
vdr20 said:
430 stainless steel is magnetic. 300 series stainless steel is non-magnetic I believe. I’m just not sure by how much it’s shielding abilities are comparable to that of mild steel.

I don’t really like the look of galvanised steel.
There's galvanised steel and there's galvanised steel. I use it in my mixer modules for inter-module screens but I would not use it where it is permanently visible.

Cheers

Ian
 
What are your thoughts on using 430 stainless steel? If it’s magnetic, should the shielding be okay? Or are there other factors at hand?
 
You're right - if it's magnetic, it's also magnetically shielding/diverting.

The magnitude of the shielding property depends on the number of field lines you can fit into a given dimension of your material, so if mag properties are weak, you can just add thickness to get to the same net effect..

/Jakob E.
 
Bear in mind that magnetic shielding reduces noise induced by magnetic fields but that noise decreases greatly with distance. You might pickup some hum if you put the unit next to some mains power cables in a wall for example but if it's vaguely far away from any high current stuff (like in the middle of a room instead of against a wall), it's probably not going to make a huge a difference if you wrap the entire thing in steel.

Electrostatic noise on the other hand has to do with charges that transmit noise over long distances (AKA radio waves). For that, any metal enclosure (like aluminum) that provides a low impedance path to earth ground is very effective at shunting it. The size of any holes in the enclosure or length of any low impedance wires protruding into the enclosure determines the wavelength of noise that will enter. So it's also important to put caps and / or chokes very close the entry point of each non-low impedance signal wire.
 
Okay thanks for your replies. I guess 430 stainless steel would work well. Does anyone know if it’s more difficult to paint due to the oxide layer that forms? I’ve had difficulty with aluminium because of this which seemed to be resolved by using steel however I’m not comfortable with the lack of corrosion resistance of mild steel. 

Has anyone tried painting stainless steel and if it’s more difficult to get the paint to adhere compared to that of mild steel?
 
vdr20 said:
What are your thoughts on using 430 stainless steel? If it’s magnetic, should the shielding be okay? Or are there other factors at hand?
430 stainless steel has about half the magnetic permeability and 1/4th the conductivity of mild steel, so it's not as good as a magnetic shield. Is it good enough? Only you can answer after you build and measure it...
Why are you so concerned with corrosion?
Painting over SS is difficult. Primers work by penetrating the atomic boundary of materials; SS is stainless because its boundary is closed.
I've had SS chassis made for some builds. I left them unfinished because the painters told me to. They'd rather see an unpainted stainless chassis than one where the paint (even epoxy powder) would peel. Leaving them unpainted was also a way to compensate the increased cost.
OTOH I've  had most of my chassis made from zinc-plated steel. The thickness of Zn is about 1/5th that of galvanized steel.
It's the standard in electronics packaging.
It can be chromated after, which will provide protection of the edges, which are left unprotected after punching/machining.
Optional chromate will also provide increased paint bonding, which is already very good without it.
SS is also mode difficult to work with.
 
vdr20 said:
Are you making the entire enclosure from stainless? I am not sure why you want to paint it. Neve modules have aluminium front panels with the controls fixed to a steel panel behind it.

Cheers

Ian
 
I'm building my own enclosure (not to look like a NEVE, but I'm using parts from a NEVE 31105) and would like the outside painted meanwhile leaving the internals bare. I don't have the facilities to zinc coat and plus I don't like the way it looks. The reason for my concerns about using mild steel is that it will rust unless I oil/wax it frequently however it has the advantage that it's extremely easy to paint. All of those problems would be fixed by using 430 stainless steel however apparently it's difficult to get paint to adhere to it.
 
vdr20 said:
I'm building my own enclosure (not to look like a NEVE, but I'm using parts from a NEVE 31105) and would like the outside painted meanwhile leaving the internals bare. I don't have the facilities to zinc coat and plus I don't like the way it looks. The reason for my concerns about using mild steel is that it will rust unless I oil/wax it frequently however it has the advantage that it's extremely easy to paint. All of those problems would be fixed by using 430 stainless steel however apparently it's difficult to get paint to adhere to it.

Is this going to be 19 inch rack mounting?

Cheers

Ian
 
I think that my only realistic option is to build the entire thing out of 430 stainless steel. I appear to live in a very humid environment and anything I do to prevent rust doesn't seem to work for very long. If I were to make it out of mild steel, I would only be able to use it in one section of where I live and I would have to oil or wax it regularly; it's just not worth the hassle and it will still rust.

Even if it is more difficult to paint 430, it would be cheaper in the long term to just repaint it if it starts to peel rather than obsessively worrying about rust and all the cost that comes with rust preventative methods.

Also the method I'm using for bending the metal is to machine a v-groove, bend the metal and fill the gap with silver solder. There's no way I can apply oil if there is a gap and it will most likely just rust. On top of that, all the screw holes and supports inside would just make it a nightmare to wax it regularly.

Also, I want a heavily brushed finish on part of the exterior casing which apparently makes the steel more likely for corrode.

 
vdr20 said:
Also the method I'm using for bending the metal is to machine a v-groove, bend the metal and fill the gap with silver solder.
I believe this won't work with stainless steel. Have you tried?

Also, I want a heavily brushed finish on part of the exterior casing which apparently makes the steel more likely for corrode.
Haven't you considered using aluminium? That would solve several of your problems.
 
abbey road d enfer said:
430 stainless steel has about half the magnetic permeability and 1/4th the conductivity of mild steel, so it's not as good as a magnetic shield. Is it good enough? Only you can answer after you build and measure it...
...….

Abbey,

Could you please provide a link for this info/reference?

I have this attached (part of a) paper which gives 430 SS a permeability of 500 with reference to copper.

But yes, the conductivity is given even worse than your figure.

 

Attachments

  • Magnetics_Materials.PNG
    Magnetics_Materials.PNG
    369.1 KB · Views: 11
Just out of interest : how thick will the sheets be?
Even if it's 0.5mm you will need a massive machine for bending those sheets. There's a reason it's called Federstahl here in Germany...

So what's the downside to use mild-steel, get that sandblasted and powdercoated?
After that you could mix open air in the rainforest without even think about rust.

Greets


 
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