Braze Alloy-common types and forms

Most Common Braze Alloys and their Forms 

 

 BAg – 3 Braze Alloy         50% with Cadmium    1170° F           1270° F           1500° F          

BAg-3 braze alloy is the standard brazing material for Carbide tools.  Cadmium is a great health danger and is widely and heavily regulated.  Because of this, BAg-3 braze alloy is often substituted with BAg-22 or BAg-24 Braze alloys, which do not contain any cadmium.

 BAg – 7  Braze Alloy                    56% with Tin  1145° F           1205° F           1400° F          

Bag-7 braze alloy is a comparatively weak braze alloy for thin kerf saws in sawmills.  It is an excellent braze alloy for artist, hobbyist, eyeglasses, etc.   BAg-7 braze alloy is easiest to use and most forgiving.  It also has a great color match with stainless steel. 

 BAg – 22 Braze Alloy       49% with Manganese  1260° F           1290° F           1525° F          

BAg-22 braze alloy is a great replacement for BAg-3 as it gives the same kind of strength and impact protection, but does not contain cadmium.  It is not as widely used as the BAg-24 braze alloy because of the way it melts and flows out.  It is sometimes described as “gummy”. 

 BAg – 24 Braze Alloy        50% Cadmium Free    1220° F           1305° F           1550° F          

BAg-24 braze alloy is the most widely used replacement for Bag-3.  This braze alloy melts and flows out very well and is easy to use.  Charpy tests indicated a loss of strength of about 30% – 40% compared to Bag-3 resulting in greater carbide tip loss and carbide tip breakage in sawmill saws. Proper fluxing and using proper brazing techniques can greatly increase the strength of the braze joint.

Rated by Strength (Weakest Can still give 40,000 psi Tensile when used properly)

From Strongest to Weakest:

  • BAg-3 Braze Alloy
  • BAg-22 Braze Alloy
  • BAg-24 Braze Alloy
  • BAg-7 Braze Alloy

 

 Rated by Ease of use

From Easiest to Hardest (requires higher skill level)

  • BAg-7 Braze Alloy
  • BAg-3 Braze Alloy
  • BAg-24 Braze Alloy
  • BAg-22 Braze Alloy

Forms of Braze Alloy

Wire

Braze Alloy in wire form is the most common and cheapest form to purchase braze alloy in.                                     

Ribbon          

braze alloy in Ribon form is simply just wire rolled flat.  Ribbon is much more expensive form to buy braze alloy in, but can be a great labor saver.  Braze Alloy ribbon can be cut to shape with a good pair of desk scissors.                                          

Sandwich

A layer of Braze alloy ribbon on each side of a layer of Copper.  Generally in a 1:2:1 ratio.  This form of braze alloy provides stress relief as steel grows and shrinks about 3 to 4 times as much as carbide during the brazing process.  This sandwich formof braze alloy, also sometimes referred to as Trimet, is recommended for carbide shapes larger than 1” in any dimension.  It is also widely used for saws with small tips, as it is a bit cheaper than straight braze alloy and provides additional strength.                                           

Preforms or Shims

Braze alloy in special shapes such as rings formed from wire or flat parts stamped out of ribbon are called preforms or shims.  This is the most expensive form to purchase braze alloy in, but can often be the least expensive form to use due to savings in labor and material.

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