Anyone make a copper sink?

I once knew a fellow who made a copper sink by first chaining him to an anchor, and then dropping him in the ocean. He was caught, though, convicted, and then executed by the state. Be kind to coppers!

Mike Mandaville Austin, Texas building a six-inch cupola

A *lot* of hammering...and annealing.

Or welding or brazing.

Rolling, hammering, burnishing and so on.

Same as fabricating any oddly shaped sheetmetal item!

Or for that matter, you could cast one, too.

Tim

Perhaps you could plate a stainless one? Or use it as a mold to make a conductive plug on which you could form up a copper one by plating?

In terms of sheet metal fabrication, I'd be tempted to cheat and make it in three pieces - top, sides, and a pan at the bottom. Since you don't care what it looks like on the other side, you have a lot of options in brazing or welding, or even sweating a doubler srip on the outside of the joint. But I would braze or perhaps TIG and then clean up the joint on the inside... works for musical instruments...

The thicker you make it the easier it will be to work with, the more durable if you accidentally end up with some sections annealed and then not sufficiently worked to reharden them... pretty much the only downside to going too thick is cost... well, there's increased heat sinking too which makes soldering and brazing harder, but welding much easier (not as likely to melt through as with really thin stock).

If there's any way you can give all of the sides some curvature, that will probably make it a lot quieter than it would be if there were any sections of dead flat that could drumhead.

If nobody here can tell you concretely how to do it, I recommend a couple of books, available from Lindsay (lindsaybks.com). The titles are

Metal Plate Work, Tinplate Work, and Sheet Metal Drafting & Shop Problems

I've listed them in order of their probable usefulness to you. All of them have more information than you need, and there's some redundancy among them.

Briefly, you draw the sink and then use a method called triangulation to develop the curves into a flat pattern. Cut this flat pattern out of heavy sheet, bend to shape, silver solder the joints (make 'em strong) and then you can start in with the hammering. Since copper is very workable when annealed, you can get your compound curves to look pretty, but it does take some skill.

Not a small project, and I can't advise you further because I've never done it. But it is doable. (Copper sinks and counters used to be very popular aboard sailboats, because they're "grabby" -- pots and pans don't slide around as much as they do on a stainless or wood counter.)

If you decide to pursue it, consider scoping out the books first. Likely you'll save yourself some frustration that way.

Pete

Not sure where the question is in this.

You figure out the dimensions, do a mock-up in cardboard to figure out your panel dimensions. Plan for 1/2" overlaps for your seams.

Once you have the parts laid out, take the pattern to your copper and start cutting. The bending is going to be very difficult without a big sheet metal shop.

If you don't have a box and pan brake, then take your patterns to a sheet metal shop and have them cut and bend your parts. Then just clamp up the parts and solder your seams.

Personally I prefer to TIG weld copper.

Don't use anything thinner than 18 ga copper as copper will constantly oxidize and wear away, so if you use too thin of a guage yo will have tissue paper after a short while.

I would use 16 ga or heavier.

I've brazed and soldered copper, but never TIG'd it. How does it behave? Anything special about it? Compared to aluminum and steel, I mean, those being the only metals I've tig welded.

There's some fairly intense copper work in my future. Silver solder should do fine for most of it, but shoot, if I can tig it instead....

If it is an undermounted sink, could it be constructed of just two pieces? one for the sides bent into a square box and one for the pan. Use a 1/2 inch overlap. Just send it to my local machine shop to cut, bend, drill the drain hole. The pan will need a very slight concave shape toward the drain for drainage. Would a little hammering do it? Use 16 gauge, solder it up and clean the inside joints and give it a patina. Sound like a solution? And thanks to everyone for all the info

Copper requires twice the amperage of steel and aluminum when TIG welding. So start with 2 amps per 0.001" of thickness.

For welding I like 18 ga to 14 ga. Thinner gets tricky with heat control, and thicker takes too much amperage.

For filler I just use plain bare coper craft wire. I buy it in 5 lb. spools at a copper supplier.

You can use electrical wire, just strip the insulation off. I don't recommend buying the deoxidized copper TIG rod they sell in welding stores. It is very expensive and tends to be more prone to porosity.

Pulsers help a lot and using a helium rich gas mix makes things considerably easier.

When running long seams start by tacking every inch or so. There is very little shrinkage of the welds.

Helium boosts your arc heat and helps to counter the thermal conductivity of the copper.

Never re-weld a seam in copper without wire brushing off any oxides from the previous pass, or you will get porosity.

The heat affected zone (HAZ) is HUGE on copper. When done the welds will be butter soft, so a little light hammering will help to stiffen up the panels, just be careful not to stretch the seams too much or you will distort the whole piece.

You can use Silphos bronze as filler if color match isn't critical. It melts at a lower temp than copper and flows nicely. Silphos bronze is used a lot on copper for gas brazing since it is self fluxing.

Standard drain basket size in the US is a 3-1/2" hole with a 1/2" indented lip around that for the gasket to sit in.

Excellent information, thanks. I've filed your msg against the day when my own copper work begins.

I TIG weld copper pretty regularly, and generally agree with Ernie's comments. I may try a few things that Ernie suggested, thanks to Ernie for posting it.

I use deoxidized copper rod for filler, but not sure if it makes any difference. Deox rod is recommended in the copper book I have from the American Welding society.

I have noticed the welded copper is more likely to crack compared to the base material. My copper book does not generally recommend welding copper, but it is the only way to get the color match that I want.

Richard

Ernie Leimkuhler wrote:

I've welded with both deoxidized copper rod and electrical wire as Ernie suggested. I find that Ernies wire method is easier and results in a better weld. Give it a shot.

By the way Richard, can I ask what you are making?

Lane

I weld copper to produce metal sculpture. See my website for some examples.

Richard

Lane wrote:

I made an undermount copper sink a few years ago. Used 48 oz copper. Made a form of stacked plywood in a rounded rectangle shape. Bent the sheet around it to form the sides, and soldered the ends together with a copper backing strip. Bent a 3/4-inch flange at the bottom edge to solder the bottom to. Made a die set to press the depressed lip for the drain. Bought brass drain and faucets and copper plated them. Turned a nice overflow flange from a copper plumbing fitting.

The bottom scratches easily. We use ours as a potting sink, and I think I'll make a wooden grille "trivet" to go on the bottom to set the heavy pots on. If you use the sink, it will be difficult to maintain a consistent color. Relatively untouched areas will turn old-penny brown, and areas with more wear will stay brighter. Stuff in the water might cause a little verdigris in some places. An alternative is to scour it occasionally.