What is the difference between these two finishes? I have been using spar urethane but am not impressed with its durability. I have a can of polyurethane sitting around I was thinking of trying.

Due to a large amount of oil in spar urethane, it tends to be softer and pliable, unlike polyurethane which is hard and stiff, due to the lesser amount of oil in its mixture.

Oh ok, does that mean poly holds up better to regular use? Also is one more water resistant than the other?

Spar is better suited for the weather, poly is a harder finish.

Give thunderbird finish a try, it's about the best out there.

They are a sponsor here.

Call and talk to Dave.

https://tbirdarchery.com/

Any Poly will crackle on the limbs with time. You will have to regular refinishing of a bow.  With Thunderbird you will have  lifelong protection and if a refinish is need it is easy to do. Give us a call if you ever have any questions

Ok I will have to try some! I will plan to pick some up at Kalamazoo in two weeks