solder copper to brass?

[tcl]

Can i use 95% tin or perhaps silver (low content silver, electrical solder) to adhere brass to copper? I will probably not be able to say what the specific alloy the brass is. Basically, i want to use brass (cheaper. stronger, more widely available) to enclose a cu heatsink and for a few other applications where it is not important that it conduct heat well.
On a related note, i'm sure i've seen reducers that let you solder (sweat as plumbers insist on calling it) 3/8" soft cu tubing to 1/2" water pipe but none of the little hardware stores that i've stopped in around here (nyc) have them or any 1/4" fittings (1/4 nominal fittings are supposedly compatible with this _actual_ 3/8" tubing of mine. They of course also insist that such a thing doesn't exist which is an interesting phenomenon itself and worthy of its own thread. No one ever simply says "sorry we don't have that" but instead try to convince you that never, in the history of the world has such a thing been produced... and by implication that by wanting it you are possibly defective. Anyway, i think i saw such a thing plumbing water to a laboratoy ice maker... perhaps i will stop by some refrigeration shops. but now, i will sleep.

OH yeah, thanks in advance.

 

[Mr. $T$]

Yep it will stick use a lot of heat though

 

[RoadWarrior]

Yes I think you'll have a challenge getting it hot enough to stick. Look out ol' man's stovetop soldering thread. One guy called Jughead, had to use a 10,000 BTU roofing torch to solder up his copper sink, it was on the huge side though.

I'm sure I've got 3/8 to 1/2 fittings somewhere, I didn't get them from the hardware store though. I tend to pick up boxes of such junk at yard sales, for a dollar or two. Damn good deal for stuff like that usually. Got loads of plumbing bits to play around with.

Road Warrior

 

[gone_fishin]

For a quick easy to find reducer, use a valve commonly used under the kitchen sink as a shutoff. You can get them with 1/2" sweat joint on one side and 3/8" compression fitting on the other for the soft pipe.

 

[Diggrr]

I just use plain old plumbing solder. And brass, being partly copper, will easily solder well to copper with most normal common solders. I used a propane torch, cause the copper and brass will remove heat from the joint area quickly, so alot of fast heat is needed to reach soldering temps. I also use paste type plumber's flux from the hardware because it's doesn't evaporate as soon as the torch hits it.

As for the fittings, try the hardware stores that carry furnace parts (fuel oil). That's where I find the best reducers. It's in a section seperate from the plumbing parts too.

Another way to try, is with a torch and a hacksaw. Split the larger tube twice with the hacksaw (four cuts) then bend it inward, this should make the 1/2" diameter small enough to just use solder. Use flux so the solder wicks into the joint well. You could also use a flareing tool to make the end of the 3/8" tubing large enough to fit snug inside of the 1/2", then solder.

Have fun.

 

[tcl]

Much thanks for all the input! I'll probably be using my propane torch in combo with the stove burner as you are right- it is a lot of metal to keep hot (cak38).
Thanks for the leads on the fittings too.