To make a long story short, I bought some solar panels off Craigslist and I need 4 barb fittings that are no longer available. It is not a universal part it's a special threaded fitting with o-ring made by the panel company.
I figured out that 1 1/4" pvc fits perfectly, just like it would press into an elbow etc. so as my last resort I am going to glue sections of PVC into the panel. Is standard PVC glue ok to use? I don't know what type of plastic the panels are, but I remember reading that some types of plastic(maybe abs?) don't react well with the glue.