Solder copper sheets?

[iwannadie]

I have a small project I'm about to start and have some basic questions if anyone is familiar with soldering copper.

I am going to use 18 gauge copper sheets and make a small (around 12"x6"x6" starting with 12"x12" sheets) box. I'd like to solder it together and then do a patina finish on the outside. I've had some guys suggest a Mapp gas torch and others suggest a normal soldering iron. It doesn't need to be overly strong but I'd like a good solid joint. I'm not sure how heat from a torch will effect the ability to use a chemical patina finish afterwards or warpage.

Small copper sheets are sure expensive so I am hoping not to ruin a bunch in the learning phase ha. Any advice would be welcome.

 

[8Mud]

Soldering iron is the best bet, but you are going to get some solder bleed no matter what you do. You may have to sand the excess solder from the places you want to pickle.

You are going to need a lot bigger soldering iron than you think, Copper leeches the heat away quick. Matching the wattage of the iron to the thickness of your material is going to be tricky IMO. To much heat and the flux and solder are going to want to spread, too little and it isn't going to flow like you want.

Remember gravity when you do your joints, try to position the corners so gravity helps the solder flow in the right direction.

Heat control is a lot harder with a flame, it takes a lot of practice. With an iron it is matching the iron, heat, wattage to the job. Around 5-600 watts would be my best guess for 18 gauge.

 

[Talyn]

For the size of the piece you are doing you don't want to use an iron. Use silver solder (not the electronics kind) and a propane torch with a large flame. The solder will come in different temp ranges. I would recommend medium or low unless you plan soldering other things to it later. You can try mapp, but it might be too hot.

Flux the pieces of copper up. Butt them together and you can put little pieces of copper about 1/2" apart in the joint. Or you can try to stick solder it. Heat it up until the solder flows.. its best to start out heating the whole piece then concentrate on the joint. If you are doing a lap joint you can flow the solder on one piece first then reheat with the other piece on top.

Solder flows best toward the heat, not so much gravity.

Its also best to start out small and make some test pieces so you get the hang of it. I wouldn't jump right on doing the big piece if you want it to come out nice.

I've done stuff like that in the past: http://www.blackonyx.net/gal3.swf

 

[Gary Briggs]

I've tig welded copper, it's welds great. Soldering is messy.

 

[8Mud]

I've tig welded copper, it's welds great. Soldering is messy.

I was thinking of treating it like copper flashing or gutters and sanding off the excess solder. For a novice, a soldering iron is a lot more forgiving than a flame IMO. Sparingly with the flux, a tiny brush works best. Tilt your work, start from the high side and draw the solder down with the iron, add solder as needed.

I guess it is a matter of opinion. After a few miles of flashing and gutters I feel pretty comfortable with an iron.

Heat control is harder with a flame, though copper is more forgiving than tin.

Maybe try a few small pieces and see what happens. Then try your pickling solution and see how it looks with your solder joints.

I have a buddy who does stained glass windows, if your interested I could probably PM you his e-mail. He might have some tips that would help.

Using silver solder (at least the stuff I use) there is a fine line between hot enough and too hot for Copper. Flame/heat control can get tricky.

 

[iwannadie]

Thanks for the input guys, I really do appreciate it.

I think I may go the torch route first, I need an excuse to buy a torch and the cost of a high watt iron is a bit out of my reach from what I've been seeing.

Any suggestions on places to order copper? The best place I've found is actually amazon, 6"x6" 18 gauge piece for 10 bucks seems high but I can't find it cheaper sadly.

 

[iwannadie]

What do you guys think about using 18 gauge? When I first started reading up on this that seemed to be a good middle ground on thickness to be sturdy and still manageable but I am thinking maybe thinner sheets now maybe.

 

[8Mud]

Thanks for the input guys, I really do appreciate it.

I think I may go the torch route first, I need an excuse to buy a torch and the cost of a high watt iron is a bit out of my reach from what I've been seeing.

Any suggestions on places to order copper? The best place I've found is actually amazon, 6"x6" 18 gauge piece for 10 bucks seems high but I can't find it cheaper sadly.

Many of the larger building supply places (Home Depot) rent, torches, irons etc.
If you plan on using it often, buying makes sense, trying it on for size and function by renting first, may be a wise choice.