how to fix a fuel fitting tube in my fiberglass fueltank?

Hello, I want to install a fuel tap in my custom fiberglass fuel tank, but first need to fix a fitting tube in the botton side. Please can you help me how to doing, and if there is any shop that sell specific fitting tubes?

This is the tap I want to install, is from a lambretta, so I nedd to fix first a tube with thread

Your best choice if you can’t draw what you want is to take the parts to a small custom machine shop in your area and have them machine something. To attach the metal parts to the fiberglass use Hysol/Loctite 9460. It has excellent resistance to gasoline/petrol.

http://www.pingelonline.com/prodcat/fuel-valve-adapters.asp

good link, but I think they are adapter for an existing valve or tube, and I need that tube that can be fixed or glued to fueltank.

Yes I was thinking to soldering a big washer in a threaded tube to get more area to glued to the fuel tank

the plates go on with hardware screw/bolt and has a gasket to seal it.
you might try poking around advrider.com it’s a huge site world wide

I found thing interesting in that forum. They use plumbing of brass.