Brazing

[dirtline]

any one who knows help me. iam trying to braze some 1/4 square steel and i cant get the rod to melt. im using lincon copper rod with flux already on it. i cleaned the steel as well as put flux on it and hit it with mapp gas which i was told would be enough for this job. but the rod would still not melt. what gives.

[Chin_Chilla]

I'd use oxy-acetolene. Set the oxygen to 5PSI and gas to 10PSI. That's the way, and only way we go it at my dads fabrication and welding shop.Don't let the flame hit the rod too much as it wont weld on good to the steel.

[zeppelin]

well im not sure why the copper int melting, but i do know that there is no way you would beable to braze steel with it even if you did get it to melt.

btw i have found (in my experience with mapp gas) that it is alot harder to braze with the flux coated rods vs the regular ones.

[Aceman]

Originally posted by zeppelin
well im not sure why the copper int melting, but i do know that there is no way you would beable to braze steel with it even if you did get it to melt.


Why not?

[SGA]

The mapp gas is not hot enough. You need oxy-acetylene

[dirtline]

thaks for the help i have another question. frist off i made a mistake in stead of copper i ment to say brass my bad. also could u point me in a better direction in the way of rod like copper coated steel nickel -silver. also one of my buddys said to look into harris safety-silv 56 does anyone know any yhing about this.. THANKS

[zeppelin]

copper and steel wont bond together, i use copper bars all of the time while im doing body work on my car because i can weld up a hole, and put the copper on one side to make sure i dont get alot of mig wire poking through.

its just like how you cant braze aluminum to steel, they just dont go together.


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Originally posted by dirtline
thaks for the help i have another question. frist off i made a mistake in stead of copper i ment to say brass my bad. also could u point me in a better direction in the way of rod like copper coated steel nickel -silver. also one of my buddys said to look into harris safety-silv 56 does anyone know any yhing about this.. THANKS


i braze steel and brass with mapp gas all of the time, make sure you are useing alot of oxygen, it will melt.

[dirtline]

i was told by the owner of a welding shop that for what i was doing mapp is fine. its hot enough to turn the steel cherry red and burn the flux so idont see why its not hot enough for what iam doing.

[zeppelin]

it is hot enough, like i said, i do it all of the time, just turn your oxygen up more, and get a hotter flame going.

[SGA]

Are you using a single torch like this?

http://www.orbitals.com/self/survey/chain/big/torch.jpg

[zeppelin]

nah, mine looks like this, sorry if i confused everybody, i always just called this thing mapp gas, but technicaly i guess its oxy-mappgas...

[Aceman]

Originally posted by zeppelin
copper and steel wont bond together, i use copper bars all of the time while im doing body work on my car because i can weld up a hole, and put the copper on one side to make sure i dont get alot of mig wire poking through.

its just like how you cant braze aluminum to steel, they just dont go together.

My mistake, I misread the post, didn't see that it said copper. DOH:rolleyes:

[Alberta_Qaudin]

k well i am a Brazer, i fix the drill bits for oil and gas rigs.......i mean i dont know every type of brazing but i do it every day, we pre-heat everything we braze to over 1000 degree's try and blast both surfaces clean with sand or median blasters, if you have dirt, rust, or oxidization on either piece of metal the alloy will run away from it and not make a good bond. we use oxy-acetylene torches at about 75psi and 100 psi, but running on large tanks so you might be better off with the lower 5 and 10psi in a small unit.

most brazing alloys will bond to any metal due to the fact that they are all alloy's and none of them are one true metal, though some will bond better with ceartin metals that other.....hence the making more than one type of alloy. make sure you have your oxogen running hot enough that it that it burns the acetylene to a clean burn or the black soot like shiet from the acetylene will make for a very weak hold.

also to try to get the alloy to start to take to the metal try to heat one piece and get a drop of alloy and then scrape that dab of alloy around while liquid with somethig. DONT over heat the alloy or you will burn it and it wont hold at all

[SGA]

dirtline,
Is yours a single mapp torch like the one in the pic I posted?

[Alberta_Qaudin]

a days work brazing

[Alberta_Qaudin]

the little round things are cutter, if they break while drilling we have ot braze new ones in if not we just have to lay a bead to cover the joint

[dirtline]

yea it is but i was told by someone i think knows what they are talking about told me mapp would be enough. i have also seen people do this as well as pictures on the internet useing just a mapp torch. but who knows

[SGA]

Well you have some good welders on here that can help you but you need to let us know if you are using a single bottle mapp torch or a dual bottle mapp torch. ( one bottle of mapp and one bottle of oxygen.)