Rivet Washing Tips
Rivet washing tips use a low-velocity cutting oxygen stream to blow rivets through a plate without damaging it. Burn the rivet heads off by placing the tip perpendicular to the rivet and not by trying to cut the rivet head off from the side as you will likely score and damage the base steel material. After removal of the rivet head, the rivet shank needs to be removed by mechanical means only.
Preheat Flame Ports
The torch cutting tip contains a number of preheat flame ports and a center passage for the cutting oxygen. The preheat flames are used to heat the metal to a temperature where the metal will react with the cutting oxygen.
Welding & Cutting Tip Basics
Acetylene cutting tips are usually manufactures with four or six preheat holes and produced to allow light, medium and heavy preheats for use with clean, dirty, or rusted plate. They are solid coppery, one piece. Rivet washing tips use a low-velocity cutting oxygen stream to blow rivets through a plate without damaging it.
Tips also are available for gouging out welds, cutting sheet metal, and other specialized uses. One-piece tips can also be used with methylacetylene-propadiene (MAP//Pro™) and propylene. They have eight preheat holes to provide the extra heat required for these gases. However, two-piece tips generally provide the best results with MAPP® gas and propylene.
Acetylene Cutting Tips
Acetylene cutting tips are usually one piece with drilled and swaged flame parts.
The six outer jets of a cutting tip are for oxygen and acetylene (Preheat Flames) and the central jet carries only oxygen. The preheat flames are not intended to melt the metal, but to bring it to its ignition temperature.
Tightening Cutting Tips
Cutting tips have metal-to-metal seating, so be sure to tighten the tip nut at 9 pounds of torque. Do not over tighten.
Two-piece tips consist of an outer shell and a splined insert. The splined insert is used to eliminate the need to drill numerous preheat holes required for cooler and slower burning gases. Different spline configurations allow different fuel gases to burn more efficiently.
Cutting tips are precision-machined copper alloy parts of various designs and sizes. They are held in the cutting torch by a tip nut.
One-piece tips are used with acetylene and are madder from copper alloy to withstand the heat of the cutting process. The copper alloy is machined, drilled and swaged over special wires to produce exact holes for preheats and cutting oxygen bores. Tolerances must be controlled carefully to produce stable flames.
Use the Proper Size Tip
Always use the proper size tip for the job. Never use an over-sized tip and then cut the fuel and oxygen back to work on a small job. This may cause tip damage, overheating, backfire and flashback.
Damaged Seating Surface
A damaged seating surface on either the tip or the head can create a dangerous condition, resulting in a backfire or flashback. This may damage the cutting torch. If the seating surface of a tip becomes damaged, do not use it. Discard the damaged tip.
Welding & Cutting Tip Design
The preheat flame ports and the cutting oxygen orifice are sized for the thickness range of metal that the tip is designed to cut.
Oxygen Cutting Process
When a piece is cut by an oxygen cutting process, a narrow width of metal is progressively removed. The width of the cut is called a Kerf. Kerf width is a result of the type of tip used, the tip size, the flow rate of oxygen and preheating gases and the speed of cutting.