A good authentic recipe would depend on where you live. If you live near the gulf coast or the west coast, asphaltum was the main ingredient and sometimes used by itself. If you live in the far north, or at high elevations, the primary ingredient was evergreen pitch with spruce being the best. Everywhere else usually has some sort of pine tree growing there, so that was used primarily, although I've seen some examples of other tree sap used after it has been boiled down a bit (I assume) to make it thicker.
If you're reproducing arrows from Central America or areas that traded with Indians from there, you can add some gum base, or natural latex or chicle, to the mix.
There were various things added to the resin or asphaltum to increase stiffness but the most common was powdered clay, fine sand, or ground up pigment of some sort. Sometimes different resins from different trees were combined and sometimes small amounts of asphaltum was thrown in as well, even in areas that were not close to the ocean. It seems like various ingredients were added to the "glue pot" on a continual basis in order to keep a good supply on hand.
The mix I use on most points is either hard pine rosin mixed with a little liquid pine tar or asphaltum powder mixed with gum base (basically roofing tar mixed with chewing gum). I've been adding pure talc powder (basically baby powder) to increase the volume and stiffness. If you dont want to buy talc powder, you can make a bunch of rock dust by rubbing two flat stones together. You can add quite a bit of powder to the mix and double the amount of glue that way.
Some tribes would mix fat with spruce resin, for example, but the fat has to be suet (the fat next to the kidneys) or some other very hard fat or the mix will be too brittle. It works the opposite of how you might think. Soft, runny fat actually makes the mix break up and shatter more easily when cool.
