PRO-POINT Harris M Manuel D'utilisateur page 10

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V 1.0 Harris Type Welder - Style M 8345076
BRAZE WELDING
Braze welding differs from gas welding because the two pieces of metal are not fused together. The brazing
rod melts at a lower temperature than the parent metal, and the braze strength comes from the surface
overlay of the brazing rod.
The advantage of braze welding over gas welding is that it is the best way to join dissimilar metals, or repair cast iron.
For instance, braze welding is the correct way to fix a pump water jacket. Almost any two metals can be joined, except
aluminum and magnesium.
Braze welding is separated into two types, depending on the type of rod used. Bronze is less expensive than silver,
and should be used when the fit between the two metals must be joined is not close. The metals must be well cleaned,
then the flame is applied to them until they become a dull red color. Both pieces must be equal temperatures or the
rod will flow to the hotter piece. Heat the rod by placing it in the flame, then dip into the flux can. Notice that the heat
causes the flux to stick to the rod. If a prefluxed rod is used, this heating and dipping step may be eliminated. Once the
rod is fluxed, and the metals are brought to the proper temperature, touch the rod to the joint, put the flame onto the
rod, and melt it. The rod then melts and flows over the heated area, bonding the metal together. Sufficient flux must be
used. Without enough flux, the rod does not "stick" to the metals.
Silver brazing is a little faster than bronze brazing. This is because silver melts at a lower temperature, and less heat
is required; however, the joint must fit tightly together. Bronze bridges a gap much better than silver. Instead of putting
flux on the silver rod, the joint should be painted with flux. The way to determine when the metals are at proper
temperature is to watch the flux. When it bubbles, it is time to apply the silver. The silver melts as it is touched to the
seam and flows over the fluxed area.
For technical questions call: 1-800-665-8685
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