I prefer using Weldon-4 with a syringe type bottle. For acrylic to pvc joints and problem spots Weldon-40 mixed and applied with a small plastic squeeze bottle or large syringe without the needle works.

If it doesnt have to look pretty I would use weldon 40... its a bunch thicker and fills in larger gaps better.however... if you spend the time to sand and fit all the pieces together weld on 4 will make a less obvious joint and a nicer looking end product

what prices have you paid for weldon? i want to make sure im not paying too much locally when i find the stuff.