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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