Tank Panel Chamfers

Chamfers are added to the tank panels to provide a void that can be filled with hot gas weld rod or extrusion welder extrudate. The chamfers are sized to accommodate the the weld filler material shape and or apparatus output. The following are standard panel chamfers. it should be noted that most welds are completed with a extrusion welder, such as the Munsch, as opposed to Laramy Products hot gas/speed welding arrangement.

Munsch MAK 18 Extrusion Welder Laramy Products Hot Gas Speed Welder

All Shell panels with the exception of covers (one sided welds) have a 45 degree x .21 deep chamfers on external corners. This has been determined to provide the weld filler optimum penetration while still allowing for fixturing of the the panels in the the locating rabbits/dados. See illustration below for 1/2 inch panels. 3/4 panels do not present a fixturing problem because the dado width increases, but the chamfer remains the same size.

Covers and pegs represent more challenging welding situation because it is only welded on one side. Further more, the change to our standard flush cover design often requires weld clean-up that results in some loss of filler material and possibly opening voids within the weld. For this reason we use deeper welds on the covers to allow more filler material to flow below the cover surface. This results in a stronger and more reliable sealing weld. Standard cover chamfers are 0.375 x 45 degrees on cover panels edges. Cover chamfers on side walls and longitudinals should/can only be a maximum of 0.143 x 45 degrees.

Because the longitudinal panels require machining on both sides the maximum chamfer size is .143 X 45 degrees. See illustration below. From a practical standpoint, the depth should be slightly less to allow for a surface for the bearing of the router to rest on. The shell walls are the same in order to standardize.

The standard cover Deep Vee route is shown below. This was originally developed to handle the requirements on Oshkosh, It is now our standard on all tanks. See the weld joint preparation below. Drawing with full instructions can be found here. 980-1002B.pdf.

The peg chamfers posed another problem because going deeper than .3125 didn't leave enough material for the router bearing to ride on during the part dislodging/delaminating step. This resulted in the holes being machined to a larger diameter and caused weld sealing issues. Cutting the the two inch round disks out completely resulted in a hazardous situation in which the center material drop could be expelled at high speeds or ingested by the the chip vacuuming and damaging the the equipment. A solution was ultimately developed were the peg holes were completely milled out instead of just cutting out the internal shape. This allowed the peg chamfers to be properly sized at .375 deep x 45 degrees. As noted in work instruction 7P11W13, The molded pegs are not to be cleaned with any secondary operations due to a concern with damaging the wall.

The finished peg with extrusion weld is shown in the picture below. No clean-up is required.

Weld gauges were developed to calibrate tools and verify the finished part and assembled weld joint was properly prepared. Find more information on weld gauges here. Weld Gauges