C) sealing the hole by connecting one end of a tube of a predetermined length to the outside of the burr, compressing the protruding end of the tube, and then welding {HEAD ~ the compressed part} of {TAIL ~ the tube} 
of
C ) sealing the hole by connecting one end of a tube of a predetermined length to the outside of the burr , compressing the protruding end of the tube , and then welding { HEAD ~ the compressed part } of { TAIL ~ the tube }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL