I found additional info on the welding kit, and as a permanent repair it does not look promising!
Our popular, do-it-yourself kit is good for all plastic tank repairs such as water tanks, spray tanks, fuel tanks, ATV and snowmobile hoods, etc*. In fact, it is appropriate for any polyethylene plastic repair. Kit include has 35 or 40 watt plastic welder, a wire brush, and a welder holder. Also included is 30 feet of FUSION GRADE PE Welding Wire (stronger than the original part). Perfect for the D-I-Y. (*Please note that polyethylene can only be welded for structural integrity. It can not be glue properly
. All adhesives, glues, epoxies, etc., will eventually fail or breakdown on a polyethylene repair.)