in fig5 designed for positioning and retaining the working tools in filler pipe 12 the top of tool guide 25 is constructed with a centering collar 26 as substantially illustrated in fig5 tool guide 25 for additional stability may be constructed with a lower collar 27 when desired in conjunction with utilization of the boring and injection tool 14 the first chemical tank 28 and a second chemical tank 29 with associated chemical hoses 30 and chemical connector 31 is required some external source of compressed air 32 is required to pressurize and power the chemical tanks 28 and 29 in practicing the process of this invention first chemical tank 28 contains chemicals mixed in the proportions of 5 gallons of water pwg powder which comprises 8 3 pounds of acrylamide and n n 39 u2550 methylenebisacrylamide and beta dimethylaminopropionitrile with the second chemical tank 29 containing chemicals in the proportion of 5 gallons of water and 8 ounces of sp which is ammonium persulfate in practice it has been found that 2 gallons of the chemical are normally sufficient for sealing the exterior of one underground storage tank after sealing the exterior of the underground storage tank 10 against exfiltration of gasoline or infiltration of water the interior of the underground storage tank should be prepared for epoxy sealing this accomplished by sanding the area of tank 10 to be repaired utilizing sanding tool 33 as illustrated in fig2 and 8 sanding tool 33 utilizes a sanding shaft 34 which.