Soldering larger copper project

I’m planning a larger project using a lot of smaller copper
components. These components will be assembled and soldered
together. I have worked with copper, but in smaller groups. I’m
trying to figure out if I need to bring the entire item up to temp to
solder one small part as I would with silver, or if I can just heat
the small area that will be receiving the solder as I would with
gold. Your opinions and expertise would be very appreciated.

Sandra Graves
Blog at http://sandragravesisisrising.blogspot.com/

I have soldered a lot of copper together but they are small thin
gauge pieces - I am usually soldering to halves together to make a
bead. They seem to react more like silver than gold. Practice on a
few pieces that are not incorporated into your project and are the
same size as the pieces you will be soldering. Copper is inexpensive
so no worries.

The short answer is “It depends…”. Copper is a good conductor of
heat, second only to silver. If your flame is hot and fierce enough
then you can possibly get away with heating just the joint area, but,
depending on how quickly the heat is conducted away, you could well
find that you simply can’t get the joint hot enough to melt the
solder without heating the entire object.

You don’t mention the shape of the components; are they short and
thick, or long and spindly? Short thick ones will conduct the heat
away much faster than long thin ones. Conserving the heat with close
fitting fire bricks is one technique that can help, as is using two
torches: one large bushy flame to create a background heat, and a
small concentrated one to do the actual soldering. As I said at the
beginning, “It depends…”.

Regards, Gary Wooding

I'm trying to figure out if I need to bring the entire item up to
temp to solder one small part as I would with silver, or if I can
just heat the small area that will be receiving the solder as I
would with gold. 

Copper soldering is like silver soldering, not like gold soldering.

Elaine
http://www.CreativeTextureTools.com

I make larger copper pieces often up to 12"X12"X12" using multiple
sections. You definitely need to bring the whole piece up to temp.
Depending on the size of the piece this may mean that you end up
using two torches to get the temperature up fast enough and then back
off with the one to help maintain the temp and come in with the other
to flow the solder seams. This however will depend on your personal
set up. The key with larger pieces I have found is not only to get
the whole piece up to temp but to get it up as fast as possible so
that as little oxidizing as possible occurs and the flux
is still in good condition. Good luck.