brazing question - wrong rod/flux?

[jbrandt]

So, I decided to try to build my first tuber. I went out and bought some 3/16 brake line and a mapp gas torch (the yellow can). I couldn't find the safety silv at any of the local stores so I went to Home Depot and bought the brazing rod that says it's for "metal working" (there were 3 main types of rod - electrical, plumbing, and metal working). I got a small tub of the flux that seemed to match it, but I can't be sure, because we all know how well the HD labels their products.

My problem is that the rod doesn't seem to want to stick to the joint. It just pools and drips on the floor (watch your toes!). I did some brazing in college as part of a machining/processing class, but it was never this hard. It would eventually stick to the rod, but it would just goop around the joint and not stick the 2 joining pieces, and it seemed to take forever for the rod to solidify.

Possible problems:
1)wrong rod/flux
2)not enough/too much flux
3)too hot or not hot enough (although I got it to glow red at one point)

I watched Double J's video like 10 times and I'm doing exactly that, so the only difference I think is the rod and flux...

Or am I really just THAT bad at brazing?!

thanks

[don_ricardocarl]

just a guess, but maybe you are not heating the brake line enough so the rod can't stick to the joint.

[jbrandt]

That was my thought at first too, so I kept the heat on the line until it glowed red hot and then it just got worse. I'm thinking the rod has too low a melting temp because the moment I put the rod in the path of the flame it melts off and drips to the floor, and I don't get a chance to place the rod where it need to go.

I guess I have to just keep screwing with it, maybe back the flame off a bit so it's not so hot...

[Double J]

JD I haven't used that type of brazing rod.
If you're dead set on using it, I'd try to heat the joints to where they are just turning red. Then apply the rod to the joint. while keeping the flam on it.

Also try dipping the rod in the flux just before trying to braze the joint.

Usually when your rod beads off it's because the metal is to hot or not hot enough.

ONly other thing I can think of is getting your brake line red hot and trying to hit it with the rod w/o a flame on it or a light flame(like pulled away to just heat it?)

If that doesn't work order some safty silv and flux from Ram welding supplies on line. If you have no way of ordering online send me a PM and well work out something.?


Jj

[red4x4]

not to hijack but i am looking for the same thing and on ram's site it says saftey silv is not recommended for carbon steel however i kno wsome of you use it...what type of flux will i need? and how far will 1 roll get me?

hijack off

[jbrandt]

Originally Posted by Double J

JD I haven't used that type of brazing rod.
If you're dead set on using it, I'd try to heat the joints to where they are just turning red. Then apply the rod to the joint. while keeping the flam on it.

Also try dipping the rod in the flux just before trying to braze the joint.

Usually when your rod beads off it's because the metal is to hot or not hot enough.

ONly other thing I can think of is getting your brake line red hot and trying to hit it with the rod w/o a flame on it or a light flame(like pulled away to just heat it?)

If that doesn't work order some safty silv and flux from Ram welding supplies on line. If you have no way of ordering online send me a PM and well work out something.?


Jj

Thanks DJ,

I'm actually going to try and get some saftey silv from the local welding shop. I was just being lazy and tried to get everything from HD, and thought it might work. If they don't have it (and they should!) I'll give Ram a try.

Thanks!!!

[Crawler374]

your problem is that brakeline comes with a galvanised coating to prevent rust from occuring when used for "brake lines" therefor, you need to get sandpaper, wire-brush, or a wire-wheel, to get that galvanise off of it. You can tell because the brakeline will look almost chrome when its clean. Then put your Flux on, heat that untill it evaporates, get the brakeline red hot, then melt the brazing rod onto the joint. And another way to tell, is that when you heap it up, whenever your finished, it should be silver and a goldish color when the joint is completed. If you dont see this you will likely see a huge clob of gunky black crap on the metal, that is burnt galvanise. All you gotta do is sand it off, more flux, then braze away!!

[jbrandt]

Originally Posted by Crawler374

your problem is that brakeline comes with a galvanised coating to prevent rust from occuring when used for "brake lines" therefor, you need to get sandpaper, wire-brush, or a wire-wheel, to get that galvanise off of it. You can tell because the brakeline will look almost chrome when its clean. Then put your Flux on, heat that untill it evaporates, get the brakeline red hot, then melt the brazing rod onto the joint. And another way to tell, is that when you heap it up, whenever your finished, it should be silver and a goldish color when the joint is completed. If you dont see this you will likely see a huge clob of gunky black crap on the metal, that is burnt galvanise. All you gotta do is sand it off, more flux, then braze away!!

Well, I went to the local welding shop and picked up some safety-silv. my problem turned out to be a combination of not cleaning the joints well enough (used a wire wheel this time), but I think it was mostly the braze I was using. Once I got the right stuff, those joints brazed right up without much fuss, and I'm now on my way to build my first tuber!

I'll post some pics when I get something that starts to resemble a rig...