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Oxy Acetylene Flame

Tuesday, 24th April 2018

An Oxy Acetylene Flame will fall loosely into one of three types:

Neutral, Oxidising and Carburising

Neutral Oxy Acetylene Flame

Neutral Oxy Acetylene Flame

A Neutral flame is achieved when there are equal amounts of Oxygen and Acetylene.

A Neutral Flame is so named because it has no chemical effect on the molten metal.

Key characteristics of a Neutral Flame are a defined Cone Flame at the base of a long feather flame.  If the correct size of nozzle is being used a Neutral flame should produce no more than a gentle hiss.

A Neutral Oxy Acetylene Flame is used for Welding, Brazing and Silver Soldering most metals and is therefore the most common type of flame to use.  A Neutral Flame is also used for Oxy Acetylene Cutting.

Oxidising Oxy Acetylene Flame

 Oxidising Oxy Acetylene Flame

An Oxidising Flame is where there is more Oxygen than Acetylene used.

Key characteristics of an Oxidising Flame are a small, sharp, more pointed looking Cone Flame at the base of a shorter feather flame.  An Oxidising Flame will have a distinct roar.

Use of a slightly Oxidising flame is more specialised, typical uses are for welding copper and zinc based metals or manganese steels.  In these cases an oxidising flame creates base metal oxide that protects the base metal.

Carburising Oxy Acetylene Flame

 Carburising Oxy Acetylene Flame

A Carburising Flame is where there is more Acetylene than Oxygen used.

Key characteristics of a Carburising Flame is a secondary feather flame, caused by the excess Acetylene burning further down the flame length. If the correct size of nozzle is being used a  Carburising flame should produce no more than a gentle hiss.

Use of a Carburising Flame is more specialised, typical uses are for welding lead, surface hardening processes or welding high carbon steels.

I hope you found this blog article useful, if things work out well for you, please feel free to post some pictures of your achievements on our Facebook Page

Please let me know what you thought of this article by leaving a comment.  Don’t worry, your email address won’t be added to a database or shared and you won’t receive any unsolicited email.

Cheers

Graham

The Welders Warehouse

Silver Solder & Braze

Wednesday, 18th April 2018

Silver Solder & Braze are both products used with either an Oxy Acetylene Torch or Oxy Propane Torch.

Silver Solder & Braze, what’s the difference?

For me, the key difference is how they work on the joint.

Silver Solder

Silver Solder is more fluid than Braze and works by being drawn into the joint by a capillary action.  So if, for example, you want to join two pieces of thin sheet metal together, you would need to overlap them.  The Silver Solder will be drawn through the joint, filling the minute crack between the two pieces of metal, bonding with the surfaces to join them.  If you tried to butt the two pieces of metal together, there simply wouldn’t be enough surface area touching to achieve a strong joint.

Silver Solder is used with a Flux, which chemically cleans the metal and keeps it clean during the Silver Soldering process.  Silver Solder is also know as Silver Brazing.

Braze

Braze on the other hand, does not get drawn into the joint, but is built up on the surface of the metal being joined, so it looks more like a weld.  Like Silver Solder, the Braze material bonds with the surface of the metal being joined.

Braze is used with a Flux, which chemically cleans the metal and keeps it clean during the Brazing process.  Brazing is also known as Bronze Welding.

What Silver Solder & Braze have in common is that neither involve melting the metal that’s being joined, that would be welding!

Silver Solder & Braze JointsIn the joint examples shown, I would use Silver Solder on the Edge & Lap Joint and Braze for the Butt, Corner & Tee Joint.

Types of Silver Solder & Braze

Whilst there are a number of Brazing Alloys on the market, for this article we’ll keep it simple and just cover the most common, C2.

C2 is a multi purpose, Silicon Bronze brazing rod that’s suited to most general purpose brazing on metals including Steel, Copper, Cast Iron and dissimilar metals.

C2 Braze is Brass Coloured and typically melts at around 875⁰C.

Most Silver Solders can be categorised by their Silver content.  The Silver content will determine the fluidity and melting temperature, the more Silver, the more fluid and the lower the melting temperature.

Most common are 33% Silver (around 720⁰C), 40% Silver (around 675⁰C) and 55% Silver (around 650⁰C).

Also available are Silver bearing Copper Phosphorus Alloys (CoPhos).  These are available with either 2% or 5% Silver and are used primarily for joining Copper to Copper, where, if the metal is clean, no Flux need be used.

Silver Solder can be used to join most common metals, including Mild Steel, Stainless Steel, Copper, Brass, Cast Iron and Dissimilar Metals.

Fluxed or Bare Wire?

Silver Solder & Braze is usually available in 2 or 3 forms:

  1. Bare Wire – (Silver Solder & Braze). This is my preferred type.  With this wire you use a powder flux.  This can be coated onto the wire as necessary by gently warming the end of the wire in your flame, then dipping in the powder.  This can be repeated as necessary.
  2. Flux Coated – (Silver Solder & Braze). This may seem like a good idea, but there are, for me, three flaws.  Flux coated wires are more expensive than bare wire.  If you need additional flux, you’ll still need a pot of powder. If the wires are bent, the flux tends to fall off!
  3. Flux Impregnated – (Braze Only). Here the flux is in little nicks on the wire.  This works very well and the wires can be bent.  The downside is that flux impregnated wires are the most expensive.

I hope you found this blog article useful, if things work out well for you, please feel free to post some pictures of your achievements on our Facebook Page

Please let me know what you thought of this article by leaving a comment.  Don’t worry, your email address won’t be added to a database or shared and you won’t receive any unsolicited email.

Cheers

Graham

The Welders Warehouse

Propane

Friday, 6th April 2018

Is Propane any good?

YES! It’s a great gas!

  • It’s versatile
  • Can be used with or without Oxygen (with correct Torch)
  • It’s cheap, compared to Acetylene
  • It’s readily available
  • It’s available without Cylinder Rental

The only real downside to Propane is that you can’t weld with it.

Pretty much everything else can be done.

With the right Torch, Oxy/Propane is great for Heating, Brazing, Silver Soldering etc.

How Propane Works in practice

Propane Gas Cylinder

Propane is a liquified gas and is stored in a cylinder with a void above the liquid.

The Liquid turns into a vapour, which fills the void until a certain pressure is reached, this pressure will depend on ambient temperature.  The colder the cylinder/liquid is, the lower the vapour pressure will be.

It is the vapour that is drawn off and travels through the Regulator, Flash Arrestor, Hose and Torch, until it meets air.  When the vapour meets air it turns into a gas, which then burns.

As vapour is drawn from the cylinder, more liquid turns into vapour, until the cylinder is empty.

Propane Problems

Propane Regulator

I’ve only ever really spoken to customers about 2 possible problems with Propane.

  1. In cold conditions, for example, the cylinder is stored in an unheated area during Winter.  The temperature of the liquid can drop so low that the Torch/Flame draws vapour off faster than the liquid in the cylinder can become more vapour.  This means the flame starts to get smaller and ultimately, goes out, giving the impression that either the cylinder has run out, or the Regulator is faulty, when in fact, neither is the case.  The only real solution to this problem is to ensure the cylinder is at room temperature when in use.
  2. If used with an Oxy/Acetylene Torch, Oxy/Propane tends to spit and fart quite a bit and the flame can easily blow out, especially when lighting.  A Torch designed for Oxy/Propane will perform FAR better and be much easier to use. Apologies for the shameless plug of our Multi-Jet LD and Multi-Jet HD Oxy/Propane Guns, but they are very, very good! Please watch the video demonstration via the “Video” tab on the pages (same video on both pages).

 

Multi-Jet Propane Nozzle

I hope you found this blog article useful, if things work out well for you, please feel free to post some pictures of your achievements on our Facebook Page

Please let me know what you thought of this article by leaving a comment.  Don’t worry, your email address won’t be added to a database or shared and you won’t receive any unsolicited email.

Cheers

Graham

The Welders Warehouse