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Staffbull

wrote:
wrote:
wrote:

So what if anything is the difference between different brands of PVA?

Concentration and components. In particular the woodworking-specific
white PVA glues are often a mix of PVA and aliphatic resins (the
"yellow glues"). You may also find additives to reduce "chalking"
(poor performance at low temperature), to reduce the quick drying when
exposed to air in an open bottle, borax to improve initial tack, or PVA
(polyvinyl alcohol this time) to make a "finer" and less viscous glue
for modelmaking.

Builders' PVA has none of these - it's just plain cheap PVA. Sometimes
there are anti-frost additives.

I normally use hide glue for woodworking. When I use PVA it's either
Titebond II or cheap builders' PVA for biscuits and some veneering
(applied cold, dried then hot pressed)

thanks for a good explanation there.

I tested some cheap by-the-gallon PVA on wood a couple of days ago,
stuck 2 strips together (without clamping them) and after a couple of
days whacked them over a stone till something broke to see what the
comparative strengths of wood and pva were, and test the glue to wood
bond. I was surprised to find it behaved as well as I could expect any
standard wood glue to do, in some areas the glue gave way and in some
it was the wood that gave first. From now on I'll use the basic PVA
when theres no need for moisture resistance, which is the one thing it
clearly cant handle.

NT

thanks for the experiment!! it's being used today to put the bedroom
floor down :-)