Weldwood is the best so far. It's inexpensive and goes a long way. I have never needed to thin it down, just use a small brush for the little spots. put a dab on both pieces let it sit till it stops shining and put your pieces together and clamp with either wood or heavy leather between clamps. And if your worried about some squeezing out and gluing the wood or heavy leather to your piece, just put wax paper on both sides.
Cheers