How to reinforce extruded sheet metal?

[adamct]

I have a relatively thin enclosure (not a purpose-built enclosure, it is an object I am improvising for use as an enclosure) made of extruded sheet metal (copper or aluminum, probably). I'd like to reinforce one section, probably by attaching a 2nd piece of thicker sheet metal to the inside. What is the best way to do this? Should I attach it using epoxy? Or is something else better? I don't want to drill holes and attach it with screws. My goal is to keep the look very clean from the outside.

Best regards,
Adam

[Paul Joppa]

Radical but here goes ... how about silicone caulk? Real silicone has a great temperature tolerance, and a thin viscous layer between metal sheets would provide some resonance damping.

Of course nothing beats an I-beam for stiffness/weight ratio. Hardware stores and model shops often have small I-beams in various metals.

[adamct]

Hmmmm....I am going to be mounting a headphone jack on the front, and RCA inputs on the rear. My concern is that the force of inserting and removing headphones/interconnects could either cause the sheet metal to be dented, warp or (in a worse case scenario) cause the headphone jack to rip out of the sheet metal entirely. So I wanted to add a sheet of metal on the inside to thicken the sheet metal of the enclosure itself, distribute the force of insertion/removal and provide a more substantial hold for mounting screws. From that perspective, I think a sheet is better than an I-beam, although I am happy to be corrected.

You think the silicone would do it? I like the temperature resistance, and the flexibility of silicone would presumably help prevent the bond from cracking/weakening due to flex in the two metal surfaces when headphones are inserted/removed.

[4krow]

Now, I have to ask, just how thin is this sheet metal?

[adamct]

It is a vintage cake pan cover. It's not tin foil, but it was really only meant to protect a devil's food cake against the occasional bee. 

I can try to measure with my calipers if relevant...

[Armaegis]

It doesn't have to be metal... some plastic or even wood would do.

[4krow]

  Dude,  we think alike. I can't hardly pass up anything that I remotely have a use for. "Excuse me sir, were you going to throw out that old light bulb? I'm going target shooting today, and..."

[VoltSecond]

Build your design on something solid. On the sockets etc., use flat head screws so you don't get dents in the thin sheet metal from handling. Round off any sharp corners and then use your decorative cover just as a cover.

I would use glue ( 2 part epoxy or non-acidic silicon glue ) to bond some thin sheets of wood to the inside of the cover to mechanically damp the metal.

[howardnair]

honestly!!--put the cake cover back over that betty crocker cake -get something else --sounds like it won't work as well as you had imagined

[adamct]

It will work just fine, thanks.

[HF9]

Haha, I know you don't like to do what everyone else does Adam, but if you change your mind, head over to Home Depot or Lowes, they have these angle bars:

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.smc-steel.com%2Fpicturefile%2FCR-3k6x9T4nOR.jpg&hash=1f340fc48390879ee97112a1bd39a34189a922b9)

Simply cut to fit and fasten underneath your chassis with a few nuts and machine screws. I've used them many times, they work like a charm.

[saildoctor]

Some epoxy systems allow for the use of fillers that can thicken enough to be used as gap fillers.  If you go that route you could also fill in the radius where the top meets the sidewall to avoid 'crumpling'.  Make sure to read the instructions on surface prep with any bonding material.

[adamct]

Thanks to everyone for the helpful suggestions!

[Armaegis]

Or do what Blue Circle Audio does and just fill the entire chassis with hot glue when you're done