brazing unlike metels " a mess"

[newbeetech]

well guy's i made a mess, i tried to weld copper to steel with the orange 45%flux coated silver rods, but the rod was creating beeds of silver and sliddiing off instead of sticking to the unlike metels,i mean i made a mess i didn't want to give up too soon so tried and tried till i did finally gave inn " uuugggg' so i dicieded to use the old faithfull 15% and did a good job by slowlly moving my torch up and down the two metels, any advice?

[rayr]

Most times you just can not beat the OLD tried and true. I always use the white paste and 15 or 45% silver. Havent' had a problem in over 40 years.

[the mojo]

Advice, yes clean the "H" out of it. Even if the steel looks new take a fitting brush to the inside and out. The copper, use a fresh piece of sand cloth. The flame keep it slowly moving back and forth around the joint. Dab with the stick to get a feel for how hot it is. When it is you can tell then with a medium amount of pressure feed it around the joint. Then use the fitting brush to clean any scale to be sure the silver is right where you want it to be.

[scottsacavsfan]

Got any pictures?
I am curently in the same boat not having great luck going copper to steel
Let me know this turns out

[referrob]

good clean surfaces, white paste, silver solder, nitrogen shield, a good hot tourch with the proper size tip, and lots and lots of practice will make a good professional joint every time.

[gbfromsd]

it's important to note that steel does not conduct heat as well as copper. heat a piece of steel and you'll see it gets cherry red, but only exactly where the flame tip is. when brazing copper to steel, preheat the copper till you get a melt then move to the joint and feed. when it starts to flow keep the flame on the steel, only on the steel. it should suck right in. as soon as your flame leaves the steel, so will your filler. keep your flame moving to keep the copper up but only feed when the flame is on the steel. don't overdo it cause that 45 turns to water and runs like crazy. I only use Harris white past and 45%.

also, dont think about trying to leave a fillet - aint gonna happen. that 45 is thin enough it will capillary action throughout the joint.

[t527ed]

never had any trouble with 15% and white flux.

as others said it must be CLEAN.

[Airmechanical]

never had any trouble with 15% and white flux.

as others said it must be CLEAN.

ditto!



.

[onetime]

it's important to note that steel does not conduct heat as well as copper. heat a piece of steel and you'll see it gets cherry red, but only exactly where the flame tip is. when brazing copper to steel, preheat the copper till you get a melt then move to the joint and feed. when it starts to flow keep the flame on the steel, only on the steel. it should suck right in. as soon as your flame leaves the steel, so will your filler. keep your flame moving to keep the copper up but only feed when the flame is on the steel. don't overdo it cause that 45 turns to water and runs like crazy. I only use Harris white past and 45%.

also, dont think about trying to leave a fillet - aint gonna happen. that 45 is thin enough it will capillary action throughout the joint.

I've always felt that the steel heats faster, when I heat the copper and then move to the steel but pull the torch away so not to overheat, which is what happened in this case because the solder was beading up. 45% with flux is the greatest thing, I've fixed cast iron small engine blocks with it and they've held for years.

[aprophet]

Hello Newbee and Scott sounds kinda like your not getting it hot enuf i hav,nt tried the newfangled rod with the flux with it for copper to copper i use 15% for diff coper to steel,brass or whatever i use the white past made by harris and the 45% wire soldr for cast iron i use brass brazing rod from a welding supply also i use a rosebud type tip on a oxy acetalyne torch i have/can use a turbo torch if it not in a tight hole i.e building condensor manifolds on can coil condensors just keep trying you guys will get it i been geting since about 1973-74 good luck hth aprophet aka david

[scottsacavsfan]

Ok so I practiced
I got a long peice of 45% from my service manager he argrees with most of you whit flux and 45 makes a good seam.
I burnt the copper a couple of times with this stuff but the end result was nice it held and didnt look that bad.
I am going to keep at it steel is alot tougher then I thought.:o

[gbfromsd]

the steel DOES heat faster, because it's not transferring heat away from the flame as well as copper does.

[nineball]

http://i61.photobucket.com/albums/h61/ws699/Picture007-2.jpg

http://i61.photobucket.com/albums/h61/ws699/Picture008.jpg

http://i61.photobucket.com/albums/h61/ws699/Picture009.jpg

http://i61.photobucket.com/albums/h61/ws699/Picture018.jpg

[nineball]

the steel DOES heat faster, because it's not transferring heat away from the flame as well as copper does.

I agree... I always heat the copper first. Sounds like you either got it to hot or not hot enough.

In the above pictures I posted, the large pipe; I used StaySilv black paste and the wire roll of 45%. Black paste is recomended because it can withstand longer durations of heat before breaking down I believe the pipe was 3 1/8. I used the white paste flux on the small 1 1/8 pipe. Sorry I did not get any close ups of the large pipe (copper to steal). I have used the flux coated rod and have had great results.