Originally Posted By: mechtech2
Titebond III is softer than the old Titebond. For some applications, it is worse than before.
Luthier repairs come to mind.
That is what I learned on my internet quest of Titebond glues, but not sure if "softer" is the correct description. While you move up the line from regular to type III, you gain a VERY tiny amount of bond strength, but the amount of "creep" also increases. Creep is described as the "plastic", or movement of the glue joint under stress and heat. So, a violin neck under string tension, sitting in a car window, could literally come apart. No PVA glues are recommended for structural repairs due to this "plastic" nature under heat/stress.
Here is something that will shock you Tempest about the so called water proofness of Titebond III: assuming this guy is who he claims......
http://www.thewoodwhisperer.com/articles/differences-between-titebond-glues/ Hugh D Evans near the bottom......quote:
"I stumbled across this page while searching for good published examples of Titebond II’s long term durability when used in exterior applications and couldn’t resist chiming in… I’m a Technical Specialist with Franklin International.
Titebond III was designed to pass the ANSI/HPVA Type I water resistance specification, which doesn’t entail great water resistance so much as high temperature water resistance. This makes it uniquely well suited to applications where steam or boiling water may be encountered, the best example being cutting boards. Despite the fact that no one recommends it, when your cutting board finally runs through a dishwasher it won’t delaminate if you used Titebond III.
Under typical environmental conditions Titebond II and Titebond III are equally resistant to water. However, Titebond III exhibits greater thermal plasticity, which is a technical way of expressing that it loses more strength as temperature increases. Since all PVA adhesives form a plastic film when dried this plastic will effectively melt once a sufficiently high temperature is reached. Titebond Original and Titebond II lose about 50% of their strength at 150"
Study their website regarding II vs. III and they say the only reason to choose III is if you need more working time or lower temp. use. Both are "water resistant". Strength differences are marginal to none.
Their marketing infers good, "premium", and "ultimate", regarding regular, II, and III. But investigation reveals a different story. Cabinet/furniture makers are better off with the regular, not the III, to avoid joint "creep". Some people have chastised Franklin for advertising "waterproof ultimate" glue, when the above quote and their website mention water "resistant".
To me, I don't specialized enough and it makes no difference. But it seems the extra cost of III is not warranted (like synthetic oil vs. dino for a 3k OCI, average conditions).