How To Repair an Aluminum Coil with Lucas Milhaupt AL822

Posted by Bob Cristan on Jun 23, 2023

Aluminum condensers and evaporators are now found extensively in the HVAC/R field.    

For installation and repairs, Lucas Milhaupt has the product to get the job done right.

Our AL822 is a zinc/ aluminum rod with a flux core, so no separate fluxing step is required.  It can be used to both join and repair aluminum to aluminum and aluminum to copper. 

Keeping in mind that aluminum has a melting point of 1218 degrees, using correct brazing technique is the key.  AL822 flows at 900 degrees.  It is difficult to visually see the color change of aluminum as it is heated, so we use the alloy rod itself as a temperature indicator by tapping the rod on to the surface.

The first step in the process is to clean the area thoroughly with a stainless-steel brush.  If oil is present- spray with a non-flammable degreaser. Using any fuel (propane, Mapp, air acetylene, or oxy acetylene), apply heat with the tip of the flame and touch the surface with the tip of the rod. As you heat it is essential that you place the rod at 12:00 on the surface to allow the alloy to flow and the flux to activate.   As the alloy begins to flow, pull the heat back so not to overheat and melt the aluminum.  After the joint cools, we then clean and then visually inspect to ensure a leak tight repair.

When joining copper to aluminum, the same process is done the only difference is the heat is placed on the copper and transfers to the aluminum.

To see how this is done with our AL822 brazing rod watch our video here:


Topics: HVAC/R, Aluminum, Brazing Tips