I wish people would stop perpetuating the myth that Yellow glues are somehow better , its a marketing gimmick that has been aroud 40 years. PVA's are defined by the D rating, D1-4 which is a measure (in general terns) of the resisitance to degradation of water. Yellow glues, are in general, D3 PVA's, which are also known as water resistant or cross linking PVA's and they have a yellow dye added. Two part PVA's are D4 which is the top rating and generally require an external hardener / catalyst to cross link them above D3. (That being said my company has the first stable one part D4 on the world market, but i am not here to market anything).We sell white and yellow D3's and their is zero differece between them except the colour.

The strength of ANY PVA will be similar, because PVA works by penetration of the polymer into the woodfibre, even a D2 will give you fibre tear and not adhesive failure. The difference is the water resistance (due to cross linking, and also solid content. D3 and higher have solids around ~50% whereas a lot of D2 have solids around 30% (or even lower), which means you get less effective glue for per ml


QUOTE=Mike Jefferys.]Not all PVA's, even if apparently the same generically, are the same. Like so much else in recent times common or garden white PVA's are often re-packs from imported sources where quality maybe suspect and where quality control is also an issue. There are now a range of PVA's from single pack white right through to two pack cross-linking. In the middle are so called yellow glues which have a harder cure, lower creep, machine better and which offer a much stronger glue up. It also glues slightly greasy timbers like silky especially well (it was actually formulated in part to glue MDF which has a waxy feel). We market AV180 as our House brand. It's made by AV Syntec in QLD. We date every bottle with a use by (which BTW is a very conservative time) and a batch code. It can be mailed in the regular post. Final points. You usually get what you pay for. Expect to pay high teens to low twenties for a 1/2 litre.
Apologies if the ad offends
Mike Jefferys
http://www.thewoodworks.com.au/detai...qskudata=C0003[/QUOTE]