Steel for enclosures

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
john12ax7 said:
I've always liked the look of the yellow zinc plating. But other than appearance, would stainless steel be a viable option since it has corrosion resistance?

Unfortunately stainless has no magnetic shielding properties.

Cheers

Ian
 
That makes sense regarding stainless.  I did a little more research on it,  it seems some stainless is ferromagnetic,  but the 300 series is not,  which is unfortunately the one commonly used in sheet metal fabrication.
 
I gave close inspection to my galvanneal chassis that have been in damp storage for a few years and there is a fine line of iron oxide on one side of the sheared edge
 
shabtek said:
I gave close inspection to my galvanneal chassis that have been in damp storage for a few years and there is a fine line of iron oxide on one side of the sheared edge

As I recall, you shear/punch/bend the sheet metal and THEN plate it to avoid bare steel edges which will rust.

Bri

 
Look for cadmium-plated steel. It was the standard surface treatment decades ago.
Check if permitted in your country. I'm not sure it is permitted anymore in France.
Now advantageously replaced with vinyl-covered zinc-protected steel.

https://www.finishing.com/355/28.shtml
 
Thinking back to Neve modules....I used to maintain an 8068 desk for a friend/client, and the steel parts were plated with perhaps Chrome.  Not mirror-finish like the bumpers on a 1950's Cadillac, but pretty shiny.

Bri

 
Brian Roth said:
As I recall, you shear/punch/bend the sheet metal and THEN plate it to avoid bare steel edges which will rust.

Bri
That was a long time ago. Today, the metalworkers get the sheet metal zinc-plated and vinyl-coated. Punching and shearing leaves parts unprotected. In a standard studio environment is is not a serious issue. Planned obsolescence makes sure the unit goes duff before it's rusted to the bone.
Now it's a different story if you install the gear in a boat.
 
abbey road d enfer said:
That was a long time ago. Today, the metalworkers get the sheet metal zinc-plated and vinyl-coated. Punching and shearing leaves parts unprotected. In a standard studio environment is is not a serious issue. Planned obsolescence makes sure the unit goes duff before it's rusted to the bone.

My (german) metalworker told me the same thing for my L-Brackets.
Now I have customers in Singapore not liking the rusty look nobody in Europe ever reported ...
 
[silent:arts] said:
My (german) metalworker told me the same thing for my L-Brackets.
Now I have customers in Singapore not liking the rusty look nobody in Europe ever reported ...
For internal metal parts, I've always favoured stainless steel. Generally, these are small parts so the cost of material is irrelevant.
 
The zinc in galvaneal surface tratment reacts with the iron oxide at the raw machined edges minimizing corrosion.
I wonder if a rust neutralizing treatment/wash would adversely affect this action...? Assuming no additional protective coating will be applied.
 
I received the Zintec parts the other day. I must say I am rather disappointed. A rather dull uneven grey surface with a lot of marks on it. Not up to the usual standard of this supplier. I think I need to get plain mild steel and send it out for finishing.

Cheers

Ian
 
abbey road d enfer said:
Seems to indicate it was not vinyl-covered.

I think you are right. I have had aluminium and stainless from the same place and both had the vinyl pull off covering on them but the cold rolled mild steel never did.

Cheers

Ian
 
ruffrecords said:
I think you are right. I have had aluminium and stainless from the same place and both had the vinyl pull off covering on them but the cold rolled mild steel never did.
I guess you have to specifically ask for it. I've never seen it on unprotected steel. Only on zintech. I guess metalworkers take for granted that unprotected steel will necessarily be treated later.
 
ruffrecords said:
I received the Zintec parts the other day. I must say I am rather disappointed. A rather dull uneven grey surface with a lot of marks on it. Not up to the usual standard of this supplier. I think I need to get plain mild steel and send it out for finishing.

Cheers

Ian
Zintec is the **cheapest** usable (sort of) metal finish.

Dull gray and surface coat is easy to scratch, will *definitely*  show folding machine jaws, etc.

Chep because metalworker buys the precoated full sheet , think 600mm x 2000 mm, 1000mm x 2000mm in Europe (or here in Argentina), 3 ft by 4 or 6 or 10 ft in US/Canada, etc.

They just cut/punch/bend it and send part to be used as is, no further tretment.

Rust protection is "reasonable", just don´t let in the rain, in a condensing humidity place or even less let Coke or beer spill on it.

All machined edges (cut/ounched, etc.) are exposed and will rust eventually.

As said above, betting equipment will be junked before that.

Typical of Marshall amplifier chassis (think cheap Valvestate, not expensive MKII/Plexi reissues which deserve proper zinc plating after machining), lots of Laney stuff, generic computer SMPS or even internal chassis elements, etc.

NOT meant to be "outside" where it can be seen and no protective transparent or blue peelable vinyl sheet which are used only to protect *polished/shiny/smooth blasted*  Aluminum or Stainles Steel surfaces.
Acrylic or "high impact" plastic sheets also come with a protective film.

So if you want a good durable finish machine your sheet metal and then plate or paint it.

Cold rolled steel can be passivated, it´s called Phosphatization.
Surface n
becomes relatively stable, but dull and pearl gray in colour.

In general it´s not meant to be used on its own but to passivate steel , dissolve preexisting oxide spots and provide an *excellent*  base for painting.

When I am out of speakers, a new batch takes about 1 Month from raw steel to packaged speaker, so to satisfy anxious customers I pull a dozen frames, phosphatize and spray paint them , then assemble and deliver.
The others get the usual bluish Zinc plating.
Customers are happy.
 
Many thanks for the insight. I tried some Zintec and I am not happy with the appearance. I think I will use cold rolled mild steel, drill the holes I need and then have it treated - could be passivation, plating or painting - I think I prefer plating. Just need to find somewhere local to d o it.

Cheers

Ian
 
Back
Top