Signal Feedthrough Box Weld Procedure

The procedure is as follows: (1) Firmly bar clamp the box together in all directions. When all directions have been secured, tack weld each outside seam of the box in 4 or 5 places along it's length. Remove clamps and proceed to weld all outside seams. Care should be taken that the maximum weld cross section does not exceed 1/16-inch x 1/16-inch. (2) To help stabilize the metal as it cools, we will install all slot plugs, (MC-223665), and one side cover plate, (MD-223637). Inside welds for this side plate will be made thru the opposite side flange. Weld cross sections should be held to a 1/16-inch maximum depth and width. (3) Weld the inside of the end plates, (MD-224535), using the weld relief as filler material. After the box has cooled, weld the top plate (ME-2244533) to the side flange, (ME-224536) and then to the bottom plate (ME-223534). (4) Repeat this procedure for the opposite side. (5) Helium leak check the welds, inside and out, by plugging the slot pumpout holes and pumping on the pumpout line. Remember that the clearances are very tight in the space that is to be pumpted. Allow plenty of time for a good pumpdown and leak check. Leak detection should be on the most sensitive scale on a helium leak detector with a minimum sensitivity of 10-9 ATM CC/SEC. (6) See 30 psig. pressure test procedure