Instructions for Using LTR 720

Application: Heat the work surface, not the brazing rod, until the work surface is hot enough to flow the rod. (Just as if you were using solder.) The rod may be worked in the flame only after the work surface has reached the working temperature. You must first open the pores of the work surface for the rod to penetrate the surface. Always allow repair to cool naturally.

Thread Replacement: Stripped out threads can be easily repaired by using either of the following methods. 1) Drill out old threads (about 1/8 inch oversized). If hole is open on the bottom, seal off using steel wool or other steel (such as a piece of coffee can lid). Place a good quality steel bolt in the hole and begin heating both the bolt and work surface until hot enough to melt the rod, then flow the rod around the bolt until slightly over-filled. Position the bolt and allow to cool. When cool, break the bolt loose with a wrench and remove. This method will not work on small holes simply because the bolt will often break when being removed. The second method is the preferred technique. 2) Drill out old thread (1/8 inch oversized), block off as above, heat and fill entirely with rod. Allow to cool, file smooth, center punch, re-drill and tap. This method gives a superior set of threads and is recommended for most applications.

Joining Pieces: Tin or coat both pieces that are to be joined with the rod, move together, and reheat to form a permanent bond. If necessary, add additional rod as filler.

Working with Copper: Copper requires more heat to open the pore structure of the surface. Clean work surface and heat until you can leave a fine test streak with the rod. Continue to heat until you see the test streak starting to be absorbed into the surface. Now make your repair. CAUTION: The rod will flow onto the surface well before the streak starts being absorbed; however, the pores will not be open yet. Therefore, penetration is not occurring. Such a repair will not be strong. When the pores are opened properly, a very strong repair will result.

Filling a Large Hole: First, heat and coat or tin the inside of the hole with rod. Now, clamp a piece of steel or iron in back of the hole. Since the hole has been tinned, you can work immediately in the flame and now fill hole with rod. Allow to cool, remove steel backing, and grind or file surface to suit.

LTR 720 has the ability to bridge; therefore, holes as large as 1/4 inch can easily be covered over without dropping through. Large holes can be covered easily by sweating a patch over the hole.

Galvanized Steel and Pot Metal: Work immediately in the flame without preheating the work surface. These surfaces will melt and rod melts in with them. (Pot metal does require some practice before attempting repairs.)

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