plastic welder for gas tanks

My friend has several of the 88-90 modules and a variety of fuel tanks if it would help, but they do demand a premium. I'm in process of shipping a SWB '76-'82 fuel tank but they take a while (it's really more aggravation than its worth to get one swabbed out clean enough to ship) to get ready to ship and shipping runs between $75 to $100 after the two week wait to make it shippable.