MegaHobby has Tenax in stock, we highly recommend it over competing brands. Plastruct's glue is a solid choice as well, and Ambroid is out of business. From what we've heard, Tenax (the manufacturer) is MIA, but we have a large supply here that should hopefully last until he resurfaces: https://www.megahobby.com/products/tenax-7r-liquid-cement-1-oz-bottle.html