stainless steel for enclosure

[tangmonster]

Hi

I like designing my own enclosures for the amplifiers I build.

So far i have stuck to natural anodized alu which gives a nice offset to the standard black anodized heatsinks.

obviously getting one or two units cut , bent and anodized is costly. and by FAR the most expensive part is the anodizing.

I suppose bare brushed alu is an option but my feeling is that it will scratch too easy.
Not a Huge fan of powdercoating though you do get a clear powdercoating that will look good on brushed aluminium.

So here is my question.

I am currently designing two new enclosures. One for a big class A amp and one for a tube preamplifier.

and want to try and cheap out and not go the anodizing route and try bare brushed Stainless steel. The place that cut the metal and bend says they have a 200 per cm brush which is nice and fine.

MY Question is.

For a brushed Stainless steel enclosure is 430 steel fine or should I opt for the 304 grade?

[tangmonster]

more images

[tangmonster]

IN the end i gave brushed 430 a bash to see how it came out. I sent my drawings through and picked up the bent and punched metal yesterday.

And I am very happy.
It seems like the metal place mostly only stock 1.6mm and not 2 or 3 mm so it won't work if i need stronger enclosure but it looks GREAT!

[Ivey]

Looks very good. Yet I have never used stainless steel for home builds. It too hard for me to cut, drill, or punch; by hand.

I have a very good sheet metal machine; 3 in 1 unit. But cutting stainless on it, is asking a bit much. Alu, is no problem. I do brushed or polish Alu., or I will paint it.

But your items look very good.

Take Care


Ivey

[indianajo]

I've worked a lot of stainless NEMA 12 chassis in a food plant. You don't cut it with any normal shear, nor does plasma cutter make any kind of straight edge. You cut it oversize with a 4.5" angle grinder, then smooth the edge with the worn down 1/4" thick wheel. (Made some safety sign backings out of SS sheet, aluminum backing will dissolve in the caustic washdown process). You drill Stainless with cobalt coated drills. These are more expensive than HighSpeedSteel drills, but he toughness of HS drills has dropped so low at my local discount stores and hardware, that I buy cobalt anyway, or mail order HS from Cleveland. You punch Stainless with Greenlee punches- wears out punch very fast. Hydraulic punch driver is very useful.

[Ivey]

My spouse was really into ceramics. She wanted a Kiln and I wanted a new Collins Radio. So I built a kiln. It cost me $300.00 verses $1,230.00 in 1976 dollars.

I used stainless steel, boiler bricks, boiler backing, home made steel clamps, Tappen Over heater elements and monel 1/4" rods.

I had the stainless cut into strips wide enough to where, when bended into a U shape. The Boiler bricks would fit inside. Once I got it high enough (about) 28", 30" over all in height. It was 18" square inside. Just perfect for a Tappen Oven heater loop element. I had obtain 9 of these. 8 from the junk and one that I had to purchase new.

I space them out evenly inside the kiln, and attached them on hangers to the stainless steel. Then I used 1/2" stainless steel strips to form buss bars for the ends of the heater elements. I bent the end tips of the heater elements in an L shape, drilled holes in the stainless steel and inserted and tied the element to the buss strips, using stainless steel wire. I used the monel rods to connect to the stainless steel buss strips and connected a stove cable to the rods.

You have to heat and hammer the rods ends flat first, drill a hole through them to attach them to the buss strips.

I wrap the boiler backing board completely around the outside of the kiln, then bend and wrap stainless steel around the boiler backing board. Lock it in place with "bandit steel", then use the 8 home made clamps to hold it all together.

The kiln was 18" square inside and 28" of useful height. So that my spouse could do medium size pieces.

My spouse became the pride of the ceramic class and we became the electric company's best customer.

The kiln was good for 2,330 degrees f. The stainless steel was good up to 3,370 degrees f. It turned a beautiful gun barrel blue, the stainless steel that was inside the kiln.

Take Care


Ivey

[audi0]

Stainless steel makes a nice enclosure.
As noted by other members, of course it's a bit more difficult to work with compared to aluminium alloys.
For this application, as corrosion isn't an issue, either grade would be acceptable, although the 430 grade does fold and fabricate a little easier that the 304, no need to go to a higher chromium content 316 grade

[DualTriode]

Originally Posted by tangmonster

IN the end i gave brushed 430 a bash to see how it came out. I sent my drawings through and picked up the bent and punched metal yesterday.

And I am very happy.
It seems like the metal place mostly only stock 1.6mm and not 2 or 3 mm so it won't work if i need stronger enclosure but it looks GREAT!

Hello,
I have worked with SS for many years in industrial and food processing applications. The saying that something is easy if you know how only applies to a limited degree to working SS. SS will eat your tools for breakfast.
300 series SS is 18% chrome and 8% nickel plus and minus a little other stuff like molybdenum. The other 70 or so % is iron.
An interesting thing between the 300 and 400 series SS is that the 300 series does not have a ferromagnetic grain structure. A magnet will not attract 300 series SS.
I have been puzzled about the magnetic shielding ability of aluminum vs. steel chassis and Mu metal. Not enough to study it. SS may have some differing shielding properties. Anybody Know?
DT
All just for fun!

[Charles Darwin]

The thing when working with stainless steel is that, like titanium, it work hardens.
That is the more you are trying to bend, shear, grind or drill it, the harder it gets and the more it will resist whatever you are doing to it.
Which is why nobody makes stainless steel cars: The press tools wear out ten times faster than when using mild steel. And the press tools are some of the costliest aspects of manufacture.
Doesn't weld that easily either although no worse than aluminium…

[Ivey]

Radiation, will go through SS, like butter to a hot knife. Magnet Radiation is even worse. Just increase the flux. The lack of dense iron element atoms is the reason. Nothing there to keep it busy.

300 lacks iron, so when it is heated, there is no scaling. 400 is something I have to look into. To if it is do able for me. But sometimes I just can not get my hands on things unless I purchase it over the internet. I hate purchasing things sight unseen or just by a picture over the internet. I fear that they are only showing me the good side of things.

Take Care


Ivey