Brazing Guide

[Sidewinder]

So, most of you are builduing theyre own Systems. And the most time while building a Phase Change you spend on Brazing.
Ok this is going to be my Guide

Im using a A/O Torch System, as most of you know. You can see it in the Thread "Good bye MAP Torch":
http://www.xtremesystems.org/forums/...threadid=36325


The first part of the Guide is about the Setup.

Well ill start with the Bottles and the Pressure-reducing valves.

1. Oxigen-Bottle Valve (watch out! high pressure!), G3/4 connection
2. Acetylene-Bottle Valve Handle connection
3. Pressure-reducing valves, 1 Interstage, 2 Manometer
4. Flaming barriers, you dont need this but i recommend it

[Sidewinder]

Ok lets have a closer look on the pressure-reducing valves:

1. The connection:
This is the pressure-reducing valve for acetylene, it has a handle connection, for oxigen its a G3/4 connection. Keep it tightly closen!

2. 1. Manometer:
This one shows the pressure in the bottle.
Oxigen: about 200Bar if full
Acetylene: about 18Bar if full

3. 2. Manometer:
This one shows the pressure on the output (6), its regulatet by the big valve (4).

4. Diaphragm Valve:
This regulates the pressure on the output (6), when turning it left the diaphragm eases, pressure falls. Turning right causes the oposite. Set the pressure for Acetylene between 0.5 and 0.55 Bar (if not differently indicated). The pressure for Oxigen is indicated at the tip.

5. Closing Valve:
The last valve, closes/opens the output (6)

6. Output:
Oxigen pressure-reducing valves have a left-hand thread, Acetylene pressure-reducing valves a right-hand thread.

[Sidewinder]

Lets go on with the torch itself.

1. The tip:
There are several sizes of tips, smallest i've ever seen was a 0.5 ~ 1.0 mm tip. This is a 1-2mm tip. Keep nozzle clean, to provide a "bad" flame.

2. The pipe:
This is a copper Pipe, you can bend it. Those are really comfortable if you must braze around a corner or something like this
(Hehe cleaned it just for you )

3. The connection:
This is a Star connection, you can easily change the tips without needing any tools. Keep this also clean!
The gases get mixed in here (4;5)

4. Oxigen Valve:
Non-adjustable, if you open it you'll have full pressure.

5. Acetylene Valve:
This is adjustable. You can adjust the pressure while brazing at this model. If your torch supports this, nice If not, get a new one LOL ;D
Just kidding :P, but its more comfortable.

6. Connection for the hose.
Well... you put the hose on it
Oxigen: left-hand thread
Acetylene: right-hand thread

[Sidewinder]

There are severall brazing rods.

I have 6 different, 3 specially for copper:

1. Silver:
Really expensive!, but very efficent. I like it, it distributes itself excelent, and you have short brazing times.

2. Silfoss 94:
Most economical brazing rod, very cheap and efficent. It's a mix of copper and phosphorus. You dont need a fluxing agent. I have 10kg of it
Maybe the name Silfoss 94 is not known in your shop. It's 94% copper and 6% phosphorus.

3. Brass/MS60:
The standard rod, nothing special. Silfos 94 costs the same and is more efficent.

[Epsilon]

i want that torch

[berkut]

make pics of how you braze, some peapole would like to see it.

i played with a oxy torch, really nice thing, gotta love it.

[saratoga]

Thanks for the info about brazes. I wasn't sure if i should use the copper and phosphorus stuff or brass.

[Sidewinder]

Originally posted by berkut
make pics of how you braze, some peapole would like to see it.

i played with a oxy torch, really nice thing, gotta love it.

Ill handle that tomorow... also security etc.

[hatemi]

Very nice to see someone showing all the noobs (I have to admit that even tough I have used O/A torches on many ocasions in past ten years, I'm still a noob nonetheless) how to do this right. yesterday I tried to braze my evap on propane stove and with too low power torch and I just couldn't get it hot enough to make a good joint(and Im not talking about kannabis here ) Next weekend I'm going to my parents house again and use the neighbours Oxygen/Acetylen torch that I used when brazing my DI/LN2 container. It had all the power to get the whole tube and base hot enough nicely

[Redwolf]

What are you setting the pressures at?
Common for that type of tip is 5 acetylene and 20 Oxygen (psig)

I use a rose bud tip most of the time. Suggested setting for it are 7-9 on both.

[megahurtz-oc]

hey fill some ballons with the acetylene and...... wait bad idea some one here will do it.

[Redwolf]

Those are great for the 4th.

[Sidewinder]

Originally posted by Redwolf
What are you setting the pressures at?
Common for that type of tip is 5 acetylene and 20 Oxygen (psig)

20 Psi Oxigen on the Manometer? Thats pretty low... I have 36 for Oxigen, 8 Psi for Acetylene.

Im going to do some more today, but im still a bit tired

megahurtz-oc
hey fill some ballons with the acetylene and...... wait bad idea some one here will do it.

Acetylene is no toy

[Sidewinder]

So now lets go on with the "interesting" part

First of all how to lite the torch, its quite simple and i took a video of it.
First open the Oxigen Valve 1/4 and more, than the Acetylene (i open it about 1/8, depending on torch). Get the lighter and lite the torch as you can see in the Video (WMV-Format, 452Kb):
http://www.side-radio.de/side/XS/LitTor.WMV

The flame should look like this:

[Sidewinder]

Lets have a closer look on the flame.
There are 3 "Zones", the outer cone (1, about 2600°C hot), the hotest point (2, about 3100°C hot) and the inner cone (2, 1800°C "cold"). Correct me if im wrong with the temps.

This pic was took throught a special filter:

[berkut]

i looked @ that movie... your making a BIG nono... first you should fire up acetylene (w/o oxygene) and than let oxygene in... theres a risk of explosion using your way

[Sidewinder]

Originally posted by berkut
i looked @ that movie... your making a BIG nono... first you should fire up acetylene (w/o oxygene) and than let oxygene in... theres a risk of explosion using your way

Thats a big nono ... while you have a flame like on a gasligther, soot gets into the connection and the setup gets damaged.
There is no risk of a explosion btw, concentration it too low.

Can i go on with my guide?

[Epsilon]

I learned that the top of the inner cone (the really top, on the edge of the 2 cones) is the hottest part.

In fact, i measured it myself on a earthgas torch and a normal lighter. 1250-1300C on the torch and 600-650c on the normal lighter .

[Sidewinder]

should be a few mm higher than the inner cone (1-2mm)...

[Sidewinder]

Anyway... i go on with my guide now.

Ok now i will show how to flare a pipe and braze them together.

Ill start with a 18mm pipe, copper. This pipe is not for refigeration technics, its a normal Pipe for sanitary.
The 18mm pipe is hard to flare, so i heat it up. Heat it up until it gets a dark red, orange is too hot.

[Sidewinder]

After heating it up i turn off my torch and flare it immediately.

[Sidewinder]

I cut off a 2nd 18mm pipe wich will be puted into the other one.
Before brazing it i have to clean it up with one of thoose metal free fleeces.

[Sidewinder]

Now i start brazing it. I heat up the upper (inner) pipe until it gets dark red and im trying to stay between dark red and red.
Here you can see how it should look like.

[Sidewinder]

This Pic isnt pretty good, the flame is much to bright. I hope you can recognize anything.

[Sidewinder]

This is a brazed 8mm Pipe, its still hot.